postgresql/src/backend/commands/cluster.c

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/*-------------------------------------------------------------------------
*
* cluster.c
* CLUSTER a table on an index. This is now also used for VACUUM FULL.
*
* There is hardly anything left of Paul Brown's original implementation...
*
*
* Portions Copyright (c) 1996-2024, PostgreSQL Global Development Group
* Portions Copyright (c) 1994-5, Regents of the University of California
*
*
* IDENTIFICATION
2010-09-20 22:08:53 +02:00
* src/backend/commands/cluster.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/amapi.h"
2019-01-15 00:54:18 +01:00
#include "access/heapam.h"
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
#include "access/multixact.h"
#include "access/relscan.h"
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
#include "access/tableam.h"
#include "access/toast_internals.h"
#include "access/transam.h"
#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/dependency.h"
1999-07-16 07:00:38 +02:00
#include "catalog/heap.h"
#include "catalog/index.h"
#include "catalog/namespace.h"
#include "catalog/objectaccess.h"
#include "catalog/pg_am.h"
#include "catalog/pg_database.h"
#include "catalog/pg_inherits.h"
#include "catalog/toasting.h"
#include "commands/cluster.h"
#include "commands/defrem.h"
#include "commands/progress.h"
#include "commands/tablecmds.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "optimizer/optimizer.h"
#include "pgstat.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "storage/predicate.h"
#include "utils/acl.h"
#include "utils/fmgroids.h"
Split up guc.c for better build speed and ease of maintenance. guc.c has grown to be one of our largest .c files, making it a bottleneck for compilation. It's also acquired a bunch of knowledge that'd be better kept elsewhere, because of our not very good habit of putting variable-specific check hooks here. Hence, split it up along these lines: * guc.c itself retains just the core GUC housekeeping mechanisms. * New file guc_funcs.c contains the SET/SHOW interfaces and some SQL-accessible functions for GUC manipulation. * New file guc_tables.c contains the data arrays that define the built-in GUC variables, along with some already-exported constant tables. * GUC check/assign/show hook functions are moved to the variable's home module, whenever that's clearly identifiable. A few hard- to-classify hooks ended up in commands/variable.c, which was already a home for miscellaneous GUC hook functions. To avoid cluttering a lot more header files with #include "guc.h", I also invented a new header file utils/guc_hooks.h and put all the GUC hook functions' declarations there, regardless of their originating module. That allowed removal of #include "guc.h" from some existing headers. The fallout from that (hopefully all caught here) demonstrates clearly why such inclusions are best minimized: there are a lot of files that, for example, were getting array.h at two or more levels of remove, despite not having any connection at all to GUCs in themselves. There is some very minor code beautification here, such as renaming a couple of inconsistently-named hook functions and improving some comments. But mostly this just moves code from point A to point B and deals with the ensuing needs for #include adjustments and exporting a few functions that previously weren't exported. Patch by me, per a suggestion from Andres Freund; thanks also to Michael Paquier for the idea to invent guc_funcs.c. Discussion: https://postgr.es/m/587607.1662836699@sss.pgh.pa.us
2022-09-13 17:05:07 +02:00
#include "utils/guc.h"
#include "utils/inval.h"
#include "utils/lsyscache.h"
#include "utils/memutils.h"
#include "utils/pg_rusage.h"
#include "utils/relmapper.h"
#include "utils/snapmgr.h"
#include "utils/syscache.h"
/*
* This struct is used to pass around the information on tables to be
* clustered. We need this so we can make a list of them when invoked without
* a specific table/index pair.
*/
typedef struct
{
Oid tableOid;
Oid indexOid;
} RelToCluster;
static void cluster_multiple_rels(List *rtcs, ClusterParams *params);
Centralize horizon determination for temp tables, fixing bug due to skew. This fixes a bug in the edge case where, for a temp table, heap_page_prune() can end up with a different horizon than heap_vacuum_rel(). Which can trigger errors like "ERROR: cannot freeze committed xmax ...". The bug was introduced due to interaction of a7212be8b9e "Set cutoff xmin more aggressively when vacuuming a temporary table." with dc7420c2c92 "snapshot scalability: Don't compute global horizons while building snapshots.". The problem is caused by lazy_scan_heap() assuming that the only reason its HeapTupleSatisfiesVacuum() call would return HEAPTUPLE_DEAD is if the tuple is a HOT tuple, or if the tuple's inserting transaction has aborted since the heap_page_prune() call. But after a7212be8b9e that was also possible in other cases for temp tables, because heap_page_prune() uses a different visibility test after dc7420c2c92. The fix is fairly simple: Move the special case logic for temp tables from vacuum_set_xid_limits() to the infrastructure introduced in dc7420c2c92. That ensures that the horizon used for pruning is at least as aggressive as the one used by lazy_scan_heap(). The concrete horizon used for temp tables is slightly different than the logic in dc7420c2c92, but should always be as aggressive as before (see comments). A significant benefit to centralizing the logic procarray.c is that now the more aggressive horizons for temp tables does not just apply to VACUUM but also to e.g. HOT pruning and the nbtree killtuples logic. Because isTopLevel is not needed by vacuum_set_xid_limits() anymore, I undid the the related changes from a7212be8b9e. This commit also adds an isolation test ensuring that the more aggressive vacuuming and pruning of temp tables keeps working. Debugged-By: Amit Kapila <amit.kapila16@gmail.com> Debugged-By: Tom Lane <tgl@sss.pgh.pa.us> Debugged-By: Ashutosh Sharma <ashu.coek88@gmail.com> Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20201014203103.72oke6hqywcyhx7s@alap3.anarazel.de Discussion: https://postgr.es/m/20201015083735.derdzysdtqdvxshp@alap3.anarazel.de
2020-10-29 01:53:41 +01:00
static void rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose);
static void copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex,
Centralize horizon determination for temp tables, fixing bug due to skew. This fixes a bug in the edge case where, for a temp table, heap_page_prune() can end up with a different horizon than heap_vacuum_rel(). Which can trigger errors like "ERROR: cannot freeze committed xmax ...". The bug was introduced due to interaction of a7212be8b9e "Set cutoff xmin more aggressively when vacuuming a temporary table." with dc7420c2c92 "snapshot scalability: Don't compute global horizons while building snapshots.". The problem is caused by lazy_scan_heap() assuming that the only reason its HeapTupleSatisfiesVacuum() call would return HEAPTUPLE_DEAD is if the tuple is a HOT tuple, or if the tuple's inserting transaction has aborted since the heap_page_prune() call. But after a7212be8b9e that was also possible in other cases for temp tables, because heap_page_prune() uses a different visibility test after dc7420c2c92. The fix is fairly simple: Move the special case logic for temp tables from vacuum_set_xid_limits() to the infrastructure introduced in dc7420c2c92. That ensures that the horizon used for pruning is at least as aggressive as the one used by lazy_scan_heap(). The concrete horizon used for temp tables is slightly different than the logic in dc7420c2c92, but should always be as aggressive as before (see comments). A significant benefit to centralizing the logic procarray.c is that now the more aggressive horizons for temp tables does not just apply to VACUUM but also to e.g. HOT pruning and the nbtree killtuples logic. Because isTopLevel is not needed by vacuum_set_xid_limits() anymore, I undid the the related changes from a7212be8b9e. This commit also adds an isolation test ensuring that the more aggressive vacuuming and pruning of temp tables keeps working. Debugged-By: Amit Kapila <amit.kapila16@gmail.com> Debugged-By: Tom Lane <tgl@sss.pgh.pa.us> Debugged-By: Ashutosh Sharma <ashu.coek88@gmail.com> Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20201014203103.72oke6hqywcyhx7s@alap3.anarazel.de Discussion: https://postgr.es/m/20201015083735.derdzysdtqdvxshp@alap3.anarazel.de
2020-10-29 01:53:41 +01:00
bool verbose, bool *pSwapToastByContent,
TransactionId *pFreezeXid, MultiXactId *pCutoffMulti);
static List *get_tables_to_cluster(MemoryContext cluster_context);
static List *get_tables_to_cluster_partitioned(MemoryContext cluster_context,
Oid indexOid);
static bool cluster_is_permitted_for_relation(Oid relid, Oid userid);
/*---------------------------------------------------------------------------
* This cluster code allows for clustering multiple tables at once. Because
* of this, we cannot just run everything on a single transaction, or we
* would be forced to acquire exclusive locks on all the tables being
* clustered, simultaneously --- very likely leading to deadlock.
*
* To solve this we follow a similar strategy to VACUUM code,
* clustering each relation in a separate transaction. For this to work,
* we need to:
* - provide a separate memory context so that we can pass information in
* a way that survives across transactions
* - start a new transaction every time a new relation is clustered
* - check for validity of the information on to-be-clustered relations,
* as someone might have deleted a relation behind our back, or
* clustered one on a different index
* - end the transaction
*
* The single-relation case does not have any such overhead.
*
* We also allow a relation to be specified without index. In that case,
* the indisclustered bit will be looked up, and an ERROR will be thrown
* if there is no index with the bit set.
*---------------------------------------------------------------------------
*/
void
cluster(ParseState *pstate, ClusterStmt *stmt, bool isTopLevel)
{
ListCell *lc;
ClusterParams params = {0};
bool verbose = false;
Relation rel = NULL;
Oid indexOid = InvalidOid;
MemoryContext cluster_context;
List *rtcs;
/* Parse option list */
foreach(lc, stmt->params)
{
DefElem *opt = (DefElem *) lfirst(lc);
if (strcmp(opt->defname, "verbose") == 0)
verbose = defGetBoolean(opt);
else
ereport(ERROR,
(errcode(ERRCODE_SYNTAX_ERROR),
errmsg("unrecognized CLUSTER option \"%s\"",
opt->defname),
parser_errposition(pstate, opt->location)));
}
params.options = (verbose ? CLUOPT_VERBOSE : 0);
if (stmt->relation != NULL)
{
/* This is the single-relation case. */
Oid tableOid;
/*
* Find, lock, and check permissions on the table. We obtain
* AccessExclusiveLock right away to avoid lock-upgrade hazard in the
* single-transaction case.
*/
tableOid = RangeVarGetRelidExtended(stmt->relation,
AccessExclusiveLock,
0,
RangeVarCallbackMaintainsTable,
NULL);
rel = table_open(tableOid, NoLock);
/*
* Reject clustering a remote temp table ... their local buffer
* manager is not going to cope.
*/
if (RELATION_IS_OTHER_TEMP(rel))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot cluster temporary tables of other sessions")));
if (stmt->indexname == NULL)
{
ListCell *index;
/* We need to find the index that has indisclustered set. */
foreach(index, RelationGetIndexList(rel))
{
indexOid = lfirst_oid(index);
if (get_index_isclustered(indexOid))
break;
indexOid = InvalidOid;
}
if (!OidIsValid(indexOid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("there is no previously clustered index for table \"%s\"",
stmt->relation->relname)));
}
else
{
/*
* The index is expected to be in the same namespace as the
* relation.
*/
indexOid = get_relname_relid(stmt->indexname,
rel->rd_rel->relnamespace);
if (!OidIsValid(indexOid))
ereport(ERROR,
(errcode(ERRCODE_UNDEFINED_OBJECT),
errmsg("index \"%s\" for table \"%s\" does not exist",
stmt->indexname, stmt->relation->relname)));
}
if (rel->rd_rel->relkind != RELKIND_PARTITIONED_TABLE)
{
/* close relation, keep lock till commit */
table_close(rel, NoLock);
/* Do the job. */
cluster_rel(tableOid, indexOid, &params);
return;
}
}
/*
* By here, we know we are in a multi-table situation. In order to avoid
* holding locks for too long, we want to process each table in its own
* transaction. This forces us to disallow running inside a user
* transaction block.
*/
PreventInTransactionBlock(isTopLevel, "CLUSTER");
/* Also, we need a memory context to hold our list of relations */
cluster_context = AllocSetContextCreate(PortalContext,
"Cluster",
ALLOCSET_DEFAULT_SIZES);
/*
* Either we're processing a partitioned table, or we were not given any
* table name at all. In either case, obtain a list of relations to
* process.
*
* In the former case, an index name must have been given, so we don't
* need to recheck its "indisclustered" bit, but we have to check that it
* is an index that we can cluster on. In the latter case, we set the
* option bit to have indisclustered verified.
*
* Rechecking the relation itself is necessary here in all cases.
*/
params.options |= CLUOPT_RECHECK;
if (rel != NULL)
{
Assert(rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE);
check_index_is_clusterable(rel, indexOid, AccessShareLock);
rtcs = get_tables_to_cluster_partitioned(cluster_context, indexOid);
/* close relation, releasing lock on parent table */
table_close(rel, AccessExclusiveLock);
}
else
{
rtcs = get_tables_to_cluster(cluster_context);
params.options |= CLUOPT_RECHECK_ISCLUSTERED;
}
/* Do the job. */
cluster_multiple_rels(rtcs, &params);
/* Start a new transaction for the cleanup work. */
StartTransactionCommand();
/* Clean up working storage */
MemoryContextDelete(cluster_context);
}
/*
* Given a list of relations to cluster, process each of them in a separate
* transaction.
*
* We expect to be in a transaction at start, but there isn't one when we
* return.
*/
static void
cluster_multiple_rels(List *rtcs, ClusterParams *params)
{
ListCell *lc;
/* Commit to get out of starting transaction */
PopActiveSnapshot();
CommitTransactionCommand();
/* Cluster the tables, each in a separate transaction */
foreach(lc, rtcs)
{
RelToCluster *rtc = (RelToCluster *) lfirst(lc);
/* Start a new transaction for each relation. */
StartTransactionCommand();
/* functions in indexes may want a snapshot set */
PushActiveSnapshot(GetTransactionSnapshot());
/* Do the job. */
cluster_rel(rtc->tableOid, rtc->indexOid, params);
PopActiveSnapshot();
CommitTransactionCommand();
}
}
/*
* cluster_rel
*
* This clusters the table by creating a new, clustered table and
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
* swapping the relfilenumbers of the new table and the old table, so
* the OID of the original table is preserved. Thus we do not lose
* GRANT, inheritance nor references to this table (this was a bug
* in releases through 7.3).
*
* Indexes are rebuilt too, via REINDEX. Since we are effectively bulk-loading
* the new table, it's better to create the indexes afterwards than to fill
* them incrementally while we load the table.
*
* If indexOid is InvalidOid, the table will be rewritten in physical order
* instead of index order. This is the new implementation of VACUUM FULL,
* and error messages should refer to the operation as VACUUM not CLUSTER.
*/
void
cluster_rel(Oid tableOid, Oid indexOid, ClusterParams *params)
{
Relation OldHeap;
Oid save_userid;
int save_sec_context;
int save_nestlevel;
bool verbose = ((params->options & CLUOPT_VERBOSE) != 0);
bool recheck = ((params->options & CLUOPT_RECHECK) != 0);
/* Check for user-requested abort. */
CHECK_FOR_INTERRUPTS();
pgstat_progress_start_command(PROGRESS_COMMAND_CLUSTER, tableOid);
if (OidIsValid(indexOid))
pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
PROGRESS_CLUSTER_COMMAND_CLUSTER);
else
pgstat_progress_update_param(PROGRESS_CLUSTER_COMMAND,
PROGRESS_CLUSTER_COMMAND_VACUUM_FULL);
/*
* We grab exclusive access to the target rel and index for the duration
* of the transaction. (This is redundant for the single-transaction
* case, since cluster() already did it.) The index lock is taken inside
* check_index_is_clusterable.
*/
OldHeap = try_relation_open(tableOid, AccessExclusiveLock);
/* If the table has gone away, we can skip processing it */
if (!OldHeap)
{
pgstat_progress_end_command();
return;
}
/*
* Switch to the table owner's userid, so that any index functions are run
* as that user. Also lock down security-restricted operations and
* arrange to make GUC variable changes local to this command.
*/
GetUserIdAndSecContext(&save_userid, &save_sec_context);
SetUserIdAndSecContext(OldHeap->rd_rel->relowner,
save_sec_context | SECURITY_RESTRICTED_OPERATION);
save_nestlevel = NewGUCNestLevel();
RestrictSearchPath();
/*
* Since we may open a new transaction for each relation, we have to check
* that the relation still is what we think it is.
*
* If this is a single-transaction CLUSTER, we can skip these tests. We
* *must* skip the one on indisclustered since it would reject an attempt
* to cluster a not-previously-clustered index.
*/
if (recheck)
{
/* Check that the user still has privileges for the relation */
if (!cluster_is_permitted_for_relation(tableOid, save_userid))
{
relation_close(OldHeap, AccessExclusiveLock);
goto out;
}
/*
* Silently skip a temp table for a remote session. Only doing this
* check in the "recheck" case is appropriate (which currently means
* somebody is executing a database-wide CLUSTER or on a partitioned
* table), because there is another check in cluster() which will stop
* any attempt to cluster remote temp tables by name. There is
* another check in cluster_rel which is redundant, but we leave it
* for extra safety.
*/
if (RELATION_IS_OTHER_TEMP(OldHeap))
{
relation_close(OldHeap, AccessExclusiveLock);
goto out;
}
if (OidIsValid(indexOid))
{
/*
* Check that the index still exists
*/
if (!SearchSysCacheExists1(RELOID, ObjectIdGetDatum(indexOid)))
{
relation_close(OldHeap, AccessExclusiveLock);
goto out;
}
/*
* Check that the index is still the one with indisclustered set,
* if needed.
*/
if ((params->options & CLUOPT_RECHECK_ISCLUSTERED) != 0 &&
!get_index_isclustered(indexOid))
{
relation_close(OldHeap, AccessExclusiveLock);
goto out;
}
}
}
/*
* We allow VACUUM FULL, but not CLUSTER, on shared catalogs. CLUSTER
* would work in most respects, but the index would only get marked as
* indisclustered in the current database, leading to unexpected behavior
* if CLUSTER were later invoked in another database.
*/
if (OidIsValid(indexOid) && OldHeap->rd_rel->relisshared)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot cluster a shared catalog")));
/*
* Don't process temp tables of other backends ... their local buffer
* manager is not going to cope.
*/
if (RELATION_IS_OTHER_TEMP(OldHeap))
{
if (OidIsValid(indexOid))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot cluster temporary tables of other sessions")));
else
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot vacuum temporary tables of other sessions")));
}
/*
* Also check for active uses of the relation in the current transaction,
* including open scans and pending AFTER trigger events.
*/
CheckTableNotInUse(OldHeap, OidIsValid(indexOid) ? "CLUSTER" : "VACUUM");
/* Check heap and index are valid to cluster on */
if (OidIsValid(indexOid))
check_index_is_clusterable(OldHeap, indexOid, AccessExclusiveLock);
/*
* Quietly ignore the request if this is a materialized view which has not
* been populated from its query. No harm is done because there is no data
* to deal with, and we don't want to throw an error if this is part of a
* multi-relation request -- for example, CLUSTER was run on the entire
* database.
*/
if (OldHeap->rd_rel->relkind == RELKIND_MATVIEW &&
!RelationIsPopulated(OldHeap))
{
relation_close(OldHeap, AccessExclusiveLock);
goto out;
}
Assert(OldHeap->rd_rel->relkind == RELKIND_RELATION ||
OldHeap->rd_rel->relkind == RELKIND_MATVIEW ||
OldHeap->rd_rel->relkind == RELKIND_TOASTVALUE);
/*
* All predicate locks on the tuples or pages are about to be made
* invalid, because we move tuples around. Promote them to relation
* locks. Predicate locks on indexes will be promoted when they are
* reindexed.
*/
TransferPredicateLocksToHeapRelation(OldHeap);
/* rebuild_relation does all the dirty work */
Centralize horizon determination for temp tables, fixing bug due to skew. This fixes a bug in the edge case where, for a temp table, heap_page_prune() can end up with a different horizon than heap_vacuum_rel(). Which can trigger errors like "ERROR: cannot freeze committed xmax ...". The bug was introduced due to interaction of a7212be8b9e "Set cutoff xmin more aggressively when vacuuming a temporary table." with dc7420c2c92 "snapshot scalability: Don't compute global horizons while building snapshots.". The problem is caused by lazy_scan_heap() assuming that the only reason its HeapTupleSatisfiesVacuum() call would return HEAPTUPLE_DEAD is if the tuple is a HOT tuple, or if the tuple's inserting transaction has aborted since the heap_page_prune() call. But after a7212be8b9e that was also possible in other cases for temp tables, because heap_page_prune() uses a different visibility test after dc7420c2c92. The fix is fairly simple: Move the special case logic for temp tables from vacuum_set_xid_limits() to the infrastructure introduced in dc7420c2c92. That ensures that the horizon used for pruning is at least as aggressive as the one used by lazy_scan_heap(). The concrete horizon used for temp tables is slightly different than the logic in dc7420c2c92, but should always be as aggressive as before (see comments). A significant benefit to centralizing the logic procarray.c is that now the more aggressive horizons for temp tables does not just apply to VACUUM but also to e.g. HOT pruning and the nbtree killtuples logic. Because isTopLevel is not needed by vacuum_set_xid_limits() anymore, I undid the the related changes from a7212be8b9e. This commit also adds an isolation test ensuring that the more aggressive vacuuming and pruning of temp tables keeps working. Debugged-By: Amit Kapila <amit.kapila16@gmail.com> Debugged-By: Tom Lane <tgl@sss.pgh.pa.us> Debugged-By: Ashutosh Sharma <ashu.coek88@gmail.com> Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20201014203103.72oke6hqywcyhx7s@alap3.anarazel.de Discussion: https://postgr.es/m/20201015083735.derdzysdtqdvxshp@alap3.anarazel.de
2020-10-29 01:53:41 +01:00
rebuild_relation(OldHeap, indexOid, verbose);
/* NB: rebuild_relation does table_close() on OldHeap */
out:
/* Roll back any GUC changes executed by index functions */
AtEOXact_GUC(false, save_nestlevel);
/* Restore userid and security context */
SetUserIdAndSecContext(save_userid, save_sec_context);
pgstat_progress_end_command();
}
/*
* Verify that the specified heap and index are valid to cluster on
*
* Side effect: obtains lock on the index. The caller may
* in some cases already have AccessExclusiveLock on the table, but
* not in all cases so we can't rely on the table-level lock for
* protection here.
*/
void
check_index_is_clusterable(Relation OldHeap, Oid indexOid, LOCKMODE lockmode)
{
Relation OldIndex;
OldIndex = index_open(indexOid, lockmode);
/*
* Check that index is in fact an index on the given relation
*/
if (OldIndex->rd_index == NULL ||
OldIndex->rd_index->indrelid != RelationGetRelid(OldHeap))
ereport(ERROR,
(errcode(ERRCODE_WRONG_OBJECT_TYPE),
errmsg("\"%s\" is not an index for table \"%s\"",
RelationGetRelationName(OldIndex),
RelationGetRelationName(OldHeap))));
/* Index AM must allow clustering */
if (!OldIndex->rd_indam->amclusterable)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot cluster on index \"%s\" because access method does not support clustering",
RelationGetRelationName(OldIndex))));
/*
* Disallow clustering on incomplete indexes (those that might not index
* every row of the relation). We could relax this by making a separate
* seqscan pass over the table to copy the missing rows, but that seems
* expensive and tedious.
*/
if (!heap_attisnull(OldIndex->rd_indextuple, Anum_pg_index_indpred, NULL))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot cluster on partial index \"%s\"",
RelationGetRelationName(OldIndex))));
2005-10-15 04:49:52 +02:00
/*
* Disallow if index is left over from a failed CREATE INDEX CONCURRENTLY;
* it might well not contain entries for every heap row, or might not even
* be internally consistent. (But note that we don't check indcheckxmin;
* the worst consequence of following broken HOT chains would be that we
* might put recently-dead tuples out-of-order in the new table, and there
* is little harm in that.)
*/
if (!OldIndex->rd_index->indisvalid)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot cluster on invalid index \"%s\"",
RelationGetRelationName(OldIndex))));
/* Drop relcache refcnt on OldIndex, but keep lock */
index_close(OldIndex, NoLock);
2002-11-23 05:05:52 +01:00
}
/*
* mark_index_clustered: mark the specified index as the one clustered on
*
* With indexOid == InvalidOid, will mark all indexes of rel not-clustered.
*/
void
mark_index_clustered(Relation rel, Oid indexOid, bool is_internal)
{
HeapTuple indexTuple;
Form_pg_index indexForm;
Relation pg_index;
ListCell *index;
/* Disallow applying to a partitioned table */
if (rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("cannot mark index clustered in partitioned table")));
/*
* If the index is already marked clustered, no need to do anything.
*/
if (OidIsValid(indexOid))
{
if (get_index_isclustered(indexOid))
return;
}
/*
* Check each index of the relation and set/clear the bit as needed.
*/
pg_index = table_open(IndexRelationId, RowExclusiveLock);
foreach(index, RelationGetIndexList(rel))
{
Oid thisIndexOid = lfirst_oid(index);
indexTuple = SearchSysCacheCopy1(INDEXRELID,
ObjectIdGetDatum(thisIndexOid));
if (!HeapTupleIsValid(indexTuple))
elog(ERROR, "cache lookup failed for index %u", thisIndexOid);
indexForm = (Form_pg_index) GETSTRUCT(indexTuple);
/*
* Unset the bit if set. We know it's wrong because we checked this
* earlier.
*/
if (indexForm->indisclustered)
{
indexForm->indisclustered = false;
CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
}
else if (thisIndexOid == indexOid)
{
Fix assorted bugs in CREATE/DROP INDEX CONCURRENTLY. Commit 8cb53654dbdb4c386369eb988062d0bbb6de725e, which introduced DROP INDEX CONCURRENTLY, managed to break CREATE INDEX CONCURRENTLY via a poor choice of catalog state representation. The pg_index state for an index that's reached the final pre-drop stage was the same as the state for an index just created by CREATE INDEX CONCURRENTLY. This meant that the (necessary) change to make RelationGetIndexList ignore about-to-die indexes also made it ignore freshly-created indexes; which is catastrophic because the latter do need to be considered in HOT-safety decisions. Failure to do so leads to incorrect index entries and subsequently wrong results from queries depending on the concurrently-created index. To fix, add an additional boolean column "indislive" to pg_index, so that the freshly-created and about-to-die states can be distinguished. (This change obviously is only possible in HEAD. This patch will need to be back-patched, but in 9.2 we'll use a kluge consisting of overloading the formerly-impossible state of indisvalid = true and indisready = false.) In addition, change CREATE/DROP INDEX CONCURRENTLY so that the pg_index flag changes they make without exclusive lock on the index are made via heap_inplace_update() rather than a normal transactional update. The latter is not very safe because moving the pg_index tuple could result in concurrent SnapshotNow scans finding it twice or not at all, thus possibly resulting in index corruption. This is a pre-existing bug in CREATE INDEX CONCURRENTLY, which was copied into the DROP code. In addition, fix various places in the code that ought to check to make sure that the indexes they are manipulating are valid and/or ready as appropriate. These represent bugs that have existed since 8.2, since a failed CREATE INDEX CONCURRENTLY could leave a corrupt or invalid index behind, and we ought not try to do anything that might fail with such an index. Also fix RelationReloadIndexInfo to ensure it copies all the pg_index columns that are allowed to change after initial creation. Previously we could have been left with stale values of some fields in an index relcache entry. It's not clear whether this actually had any user-visible consequences, but it's at least a bug waiting to happen. In addition, do some code and docs review for DROP INDEX CONCURRENTLY; some cosmetic code cleanup but mostly addition and revision of comments. This will need to be back-patched, but in a noticeably different form, so I'm committing it to HEAD before working on the back-patch. Problem reported by Amit Kapila, diagnosis by Pavan Deolassee, fix by Tom Lane and Andres Freund.
2012-11-29 03:25:27 +01:00
/* this was checked earlier, but let's be real sure */
if (!indexForm->indisvalid)
Fix assorted bugs in CREATE/DROP INDEX CONCURRENTLY. Commit 8cb53654dbdb4c386369eb988062d0bbb6de725e, which introduced DROP INDEX CONCURRENTLY, managed to break CREATE INDEX CONCURRENTLY via a poor choice of catalog state representation. The pg_index state for an index that's reached the final pre-drop stage was the same as the state for an index just created by CREATE INDEX CONCURRENTLY. This meant that the (necessary) change to make RelationGetIndexList ignore about-to-die indexes also made it ignore freshly-created indexes; which is catastrophic because the latter do need to be considered in HOT-safety decisions. Failure to do so leads to incorrect index entries and subsequently wrong results from queries depending on the concurrently-created index. To fix, add an additional boolean column "indislive" to pg_index, so that the freshly-created and about-to-die states can be distinguished. (This change obviously is only possible in HEAD. This patch will need to be back-patched, but in 9.2 we'll use a kluge consisting of overloading the formerly-impossible state of indisvalid = true and indisready = false.) In addition, change CREATE/DROP INDEX CONCURRENTLY so that the pg_index flag changes they make without exclusive lock on the index are made via heap_inplace_update() rather than a normal transactional update. The latter is not very safe because moving the pg_index tuple could result in concurrent SnapshotNow scans finding it twice or not at all, thus possibly resulting in index corruption. This is a pre-existing bug in CREATE INDEX CONCURRENTLY, which was copied into the DROP code. In addition, fix various places in the code that ought to check to make sure that the indexes they are manipulating are valid and/or ready as appropriate. These represent bugs that have existed since 8.2, since a failed CREATE INDEX CONCURRENTLY could leave a corrupt or invalid index behind, and we ought not try to do anything that might fail with such an index. Also fix RelationReloadIndexInfo to ensure it copies all the pg_index columns that are allowed to change after initial creation. Previously we could have been left with stale values of some fields in an index relcache entry. It's not clear whether this actually had any user-visible consequences, but it's at least a bug waiting to happen. In addition, do some code and docs review for DROP INDEX CONCURRENTLY; some cosmetic code cleanup but mostly addition and revision of comments. This will need to be back-patched, but in a noticeably different form, so I'm committing it to HEAD before working on the back-patch. Problem reported by Amit Kapila, diagnosis by Pavan Deolassee, fix by Tom Lane and Andres Freund.
2012-11-29 03:25:27 +01:00
elog(ERROR, "cannot cluster on invalid index %u", indexOid);
indexForm->indisclustered = true;
CatalogTupleUpdate(pg_index, &indexTuple->t_self, indexTuple);
}
InvokeObjectPostAlterHookArg(IndexRelationId, thisIndexOid, 0,
InvalidOid, is_internal);
heap_freetuple(indexTuple);
}
table_close(pg_index, RowExclusiveLock);
}
/*
* rebuild_relation: rebuild an existing relation in index or physical order
*
* OldHeap: table to rebuild --- must be opened and exclusive-locked!
* indexOid: index to cluster by, or InvalidOid to rewrite in physical order.
*
* NB: this routine closes OldHeap at the right time; caller should not.
*/
static void
Centralize horizon determination for temp tables, fixing bug due to skew. This fixes a bug in the edge case where, for a temp table, heap_page_prune() can end up with a different horizon than heap_vacuum_rel(). Which can trigger errors like "ERROR: cannot freeze committed xmax ...". The bug was introduced due to interaction of a7212be8b9e "Set cutoff xmin more aggressively when vacuuming a temporary table." with dc7420c2c92 "snapshot scalability: Don't compute global horizons while building snapshots.". The problem is caused by lazy_scan_heap() assuming that the only reason its HeapTupleSatisfiesVacuum() call would return HEAPTUPLE_DEAD is if the tuple is a HOT tuple, or if the tuple's inserting transaction has aborted since the heap_page_prune() call. But after a7212be8b9e that was also possible in other cases for temp tables, because heap_page_prune() uses a different visibility test after dc7420c2c92. The fix is fairly simple: Move the special case logic for temp tables from vacuum_set_xid_limits() to the infrastructure introduced in dc7420c2c92. That ensures that the horizon used for pruning is at least as aggressive as the one used by lazy_scan_heap(). The concrete horizon used for temp tables is slightly different than the logic in dc7420c2c92, but should always be as aggressive as before (see comments). A significant benefit to centralizing the logic procarray.c is that now the more aggressive horizons for temp tables does not just apply to VACUUM but also to e.g. HOT pruning and the nbtree killtuples logic. Because isTopLevel is not needed by vacuum_set_xid_limits() anymore, I undid the the related changes from a7212be8b9e. This commit also adds an isolation test ensuring that the more aggressive vacuuming and pruning of temp tables keeps working. Debugged-By: Amit Kapila <amit.kapila16@gmail.com> Debugged-By: Tom Lane <tgl@sss.pgh.pa.us> Debugged-By: Ashutosh Sharma <ashu.coek88@gmail.com> Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20201014203103.72oke6hqywcyhx7s@alap3.anarazel.de Discussion: https://postgr.es/m/20201015083735.derdzysdtqdvxshp@alap3.anarazel.de
2020-10-29 01:53:41 +01:00
rebuild_relation(Relation OldHeap, Oid indexOid, bool verbose)
2002-11-23 05:05:52 +01:00
{
Oid tableOid = RelationGetRelid(OldHeap);
Oid accessMethod = OldHeap->rd_rel->relam;
Oid tableSpace = OldHeap->rd_rel->reltablespace;
2002-11-23 05:05:52 +01:00
Oid OIDNewHeap;
char relpersistence;
bool is_system_catalog;
bool swap_toast_by_content;
TransactionId frozenXid;
MultiXactId cutoffMulti;
2002-11-23 05:05:52 +01:00
if (OidIsValid(indexOid))
/* Mark the correct index as clustered */
mark_index_clustered(OldHeap, indexOid, true);
/* Remember info about rel before closing OldHeap */
relpersistence = OldHeap->rd_rel->relpersistence;
is_system_catalog = IsSystemRelation(OldHeap);
/* Close relcache entry, but keep lock until transaction commit */
table_close(OldHeap, NoLock);
/* Create the transient table that will receive the re-ordered data */
OIDNewHeap = make_new_heap(tableOid, tableSpace,
accessMethod,
relpersistence,
AccessExclusiveLock);
/* Copy the heap data into the new table in the desired order */
Centralize horizon determination for temp tables, fixing bug due to skew. This fixes a bug in the edge case where, for a temp table, heap_page_prune() can end up with a different horizon than heap_vacuum_rel(). Which can trigger errors like "ERROR: cannot freeze committed xmax ...". The bug was introduced due to interaction of a7212be8b9e "Set cutoff xmin more aggressively when vacuuming a temporary table." with dc7420c2c92 "snapshot scalability: Don't compute global horizons while building snapshots.". The problem is caused by lazy_scan_heap() assuming that the only reason its HeapTupleSatisfiesVacuum() call would return HEAPTUPLE_DEAD is if the tuple is a HOT tuple, or if the tuple's inserting transaction has aborted since the heap_page_prune() call. But after a7212be8b9e that was also possible in other cases for temp tables, because heap_page_prune() uses a different visibility test after dc7420c2c92. The fix is fairly simple: Move the special case logic for temp tables from vacuum_set_xid_limits() to the infrastructure introduced in dc7420c2c92. That ensures that the horizon used for pruning is at least as aggressive as the one used by lazy_scan_heap(). The concrete horizon used for temp tables is slightly different than the logic in dc7420c2c92, but should always be as aggressive as before (see comments). A significant benefit to centralizing the logic procarray.c is that now the more aggressive horizons for temp tables does not just apply to VACUUM but also to e.g. HOT pruning and the nbtree killtuples logic. Because isTopLevel is not needed by vacuum_set_xid_limits() anymore, I undid the the related changes from a7212be8b9e. This commit also adds an isolation test ensuring that the more aggressive vacuuming and pruning of temp tables keeps working. Debugged-By: Amit Kapila <amit.kapila16@gmail.com> Debugged-By: Tom Lane <tgl@sss.pgh.pa.us> Debugged-By: Ashutosh Sharma <ashu.coek88@gmail.com> Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20201014203103.72oke6hqywcyhx7s@alap3.anarazel.de Discussion: https://postgr.es/m/20201015083735.derdzysdtqdvxshp@alap3.anarazel.de
2020-10-29 01:53:41 +01:00
copy_table_data(OIDNewHeap, tableOid, indexOid, verbose,
&swap_toast_by_content, &frozenXid, &cutoffMulti);
1998-01-10 06:19:22 +01:00
/*
* Swap the physical files of the target and transient tables, then
* rebuild the target's indexes and throw away the transient table.
*/
finish_heap_swap(tableOid, OIDNewHeap, is_system_catalog,
swap_toast_by_content, false, true,
frozenXid, cutoffMulti,
relpersistence);
}
/*
* Create the transient table that will be filled with new data during
* CLUSTER, ALTER TABLE, and similar operations. The transient table
* duplicates the logical structure of the OldHeap; but will have the
* specified physical storage properties NewTableSpace, NewAccessMethod, and
* relpersistence.
*
* After this, the caller should load the new heap with transferred/modified
* data, then call finish_heap_swap to complete the operation.
*/
Oid
make_new_heap(Oid OIDOldHeap, Oid NewTableSpace, Oid NewAccessMethod,
char relpersistence, LOCKMODE lockmode)
{
TupleDesc OldHeapDesc;
char NewHeapName[NAMEDATALEN];
Oid OIDNewHeap;
Oid toastid;
Relation OldHeap;
HeapTuple tuple;
Datum reloptions;
bool isNull;
Oid namespaceid;
OldHeap = table_open(OIDOldHeap, lockmode);
OldHeapDesc = RelationGetDescr(OldHeap);
/*
* Note that the NewHeap will not receive any of the defaults or
* constraints associated with the OldHeap; we don't need 'em, and there's
* no reason to spend cycles inserting them into the catalogs only to
* delete them.
*/
/*
* But we do want to use reloptions of the old heap for new heap.
*/
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(OIDOldHeap));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
reloptions = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions,
&isNull);
if (isNull)
reloptions = (Datum) 0;
if (relpersistence == RELPERSISTENCE_TEMP)
namespaceid = LookupCreationNamespace("pg_temp");
else
namespaceid = RelationGetNamespace(OldHeap);
/*
* Create the new heap, using a temporary name in the same namespace as
* the existing table. NOTE: there is some risk of collision with user
* relnames. Working around this seems more trouble than it's worth; in
* particular, we can't create the new heap in a different namespace from
* the old, or we will have problems with the TEMP status of temp tables.
*
* Note: the new heap is not a shared relation, even if we are rebuilding
* a shared rel. However, we do make the new heap mapped if the source is
* mapped. This simplifies swap_relation_files, and is absolutely
* necessary for rebuilding pg_class, for reasons explained there.
*/
snprintf(NewHeapName, sizeof(NewHeapName), "pg_temp_%u", OIDOldHeap);
OIDNewHeap = heap_create_with_catalog(NewHeapName,
namespaceid,
NewTableSpace,
InvalidOid,
InvalidOid,
InvalidOid,
OldHeap->rd_rel->relowner,
NewAccessMethod,
OldHeapDesc,
NIL,
RELKIND_RELATION,
relpersistence,
false,
RelationIsMapped(OldHeap),
ONCOMMIT_NOOP,
reloptions,
false,
true,
true,
OIDOldHeap,
NULL);
Assert(OIDNewHeap != InvalidOid);
ReleaseSysCache(tuple);
/*
* Advance command counter so that the newly-created relation's catalog
* tuples will be visible to table_open.
*/
CommandCounterIncrement();
/*
* If necessary, create a TOAST table for the new relation.
*
* If the relation doesn't have a TOAST table already, we can't need one
* for the new relation. The other way around is possible though: if some
* wide columns have been dropped, NewHeapCreateToastTable can decide that
* no TOAST table is needed for the new table.
*
* Note that NewHeapCreateToastTable ends with CommandCounterIncrement, so
* that the TOAST table will be visible for insertion.
*/
toastid = OldHeap->rd_rel->reltoastrelid;
if (OidIsValid(toastid))
{
/* keep the existing toast table's reloptions, if any */
tuple = SearchSysCache1(RELOID, ObjectIdGetDatum(toastid));
if (!HeapTupleIsValid(tuple))
elog(ERROR, "cache lookup failed for relation %u", toastid);
reloptions = SysCacheGetAttr(RELOID, tuple, Anum_pg_class_reloptions,
&isNull);
if (isNull)
reloptions = (Datum) 0;
NewHeapCreateToastTable(OIDNewHeap, reloptions, lockmode, toastid);
ReleaseSysCache(tuple);
}
table_close(OldHeap, NoLock);
return OIDNewHeap;
}
/*
* Do the physical copying of table data.
*
2014-01-20 18:22:49 +01:00
* There are three output parameters:
* *pSwapToastByContent is set true if toast tables must be swapped by content.
* *pFreezeXid receives the TransactionId used as freeze cutoff point.
* *pCutoffMulti receives the MultiXactId used as a cutoff point.
*/
static void
Centralize horizon determination for temp tables, fixing bug due to skew. This fixes a bug in the edge case where, for a temp table, heap_page_prune() can end up with a different horizon than heap_vacuum_rel(). Which can trigger errors like "ERROR: cannot freeze committed xmax ...". The bug was introduced due to interaction of a7212be8b9e "Set cutoff xmin more aggressively when vacuuming a temporary table." with dc7420c2c92 "snapshot scalability: Don't compute global horizons while building snapshots.". The problem is caused by lazy_scan_heap() assuming that the only reason its HeapTupleSatisfiesVacuum() call would return HEAPTUPLE_DEAD is if the tuple is a HOT tuple, or if the tuple's inserting transaction has aborted since the heap_page_prune() call. But after a7212be8b9e that was also possible in other cases for temp tables, because heap_page_prune() uses a different visibility test after dc7420c2c92. The fix is fairly simple: Move the special case logic for temp tables from vacuum_set_xid_limits() to the infrastructure introduced in dc7420c2c92. That ensures that the horizon used for pruning is at least as aggressive as the one used by lazy_scan_heap(). The concrete horizon used for temp tables is slightly different than the logic in dc7420c2c92, but should always be as aggressive as before (see comments). A significant benefit to centralizing the logic procarray.c is that now the more aggressive horizons for temp tables does not just apply to VACUUM but also to e.g. HOT pruning and the nbtree killtuples logic. Because isTopLevel is not needed by vacuum_set_xid_limits() anymore, I undid the the related changes from a7212be8b9e. This commit also adds an isolation test ensuring that the more aggressive vacuuming and pruning of temp tables keeps working. Debugged-By: Amit Kapila <amit.kapila16@gmail.com> Debugged-By: Tom Lane <tgl@sss.pgh.pa.us> Debugged-By: Ashutosh Sharma <ashu.coek88@gmail.com> Author: Andres Freund <andres@anarazel.de> Discussion: https://postgr.es/m/20201014203103.72oke6hqywcyhx7s@alap3.anarazel.de Discussion: https://postgr.es/m/20201015083735.derdzysdtqdvxshp@alap3.anarazel.de
2020-10-29 01:53:41 +01:00
copy_table_data(Oid OIDNewHeap, Oid OIDOldHeap, Oid OIDOldIndex, bool verbose,
bool *pSwapToastByContent, TransactionId *pFreezeXid,
MultiXactId *pCutoffMulti)
{
Relation NewHeap,
OldHeap,
OldIndex;
Relation relRelation;
HeapTuple reltup;
Form_pg_class relform;
TupleDesc oldTupDesc PG_USED_FOR_ASSERTS_ONLY;
TupleDesc newTupDesc PG_USED_FOR_ASSERTS_ONLY;
VacuumParams params;
struct VacuumCutoffs cutoffs;
bool use_sort;
double num_tuples = 0,
tups_vacuumed = 0,
tups_recently_dead = 0;
BlockNumber num_pages;
int elevel = verbose ? INFO : DEBUG2;
PGRUsage ru0;
char *nspname;
pg_rusage_init(&ru0);
/*
* Open the relations we need.
*/
NewHeap = table_open(OIDNewHeap, AccessExclusiveLock);
OldHeap = table_open(OIDOldHeap, AccessExclusiveLock);
if (OidIsValid(OIDOldIndex))
OldIndex = index_open(OIDOldIndex, AccessExclusiveLock);
else
OldIndex = NULL;
/* Store a copy of the namespace name for logging purposes */
nspname = get_namespace_name(RelationGetNamespace(OldHeap));
/*
* Their tuple descriptors should be exactly alike, but here we only need
* assume that they have the same number of columns.
*/
oldTupDesc = RelationGetDescr(OldHeap);
newTupDesc = RelationGetDescr(NewHeap);
Assert(newTupDesc->natts == oldTupDesc->natts);
/*
* If the OldHeap has a toast table, get lock on the toast table to keep
* it from being vacuumed. This is needed because autovacuum processes
* toast tables independently of their main tables, with no lock on the
* latter. If an autovacuum were to start on the toast table after we
* compute our OldestXmin below, it would use a later OldestXmin, and then
* possibly remove as DEAD toast tuples belonging to main tuples we think
* are only RECENTLY_DEAD. Then we'd fail while trying to copy those
* tuples.
*
* We don't need to open the toast relation here, just lock it. The lock
* will be held till end of transaction.
*/
if (OldHeap->rd_rel->reltoastrelid)
LockRelationOid(OldHeap->rd_rel->reltoastrelid, AccessExclusiveLock);
/*
* If both tables have TOAST tables, perform toast swap by content. It is
* possible that the old table has a toast table but the new one doesn't,
* if toastable columns have been dropped. In that case we have to do
* swap by links. This is okay because swap by content is only essential
* for system catalogs, and we don't support schema changes for them.
*/
if (OldHeap->rd_rel->reltoastrelid && NewHeap->rd_rel->reltoastrelid)
{
*pSwapToastByContent = true;
/*
* When doing swap by content, any toast pointers written into NewHeap
* must use the old toast table's OID, because that's where the toast
* data will eventually be found. Set this up by setting rd_toastoid.
Fix CLUSTER/VACUUM FULL for toast values owned by recently-updated rows. In commit 7b0d0e9356963d5c3e4d329a917f5fbb82a2ef05, I made CLUSTER and VACUUM FULL try to preserve toast value OIDs from the original toast table to the new one. However, if we have to copy both live and recently-dead versions of a row that has a toasted column, those versions may well reference the same toast value with the same OID. The patch then led to duplicate-key failures as we tried to insert the toast value twice with the same OID. (The previous behavior was not very desirable either, since it would have silently inserted the same value twice with different OIDs. That wastes space, but what's worse is that the toast values inserted for already-dead heap rows would not be reclaimed by subsequent ordinary VACUUMs, since they go into the new toast table marked live not deleted.) To fix, check if the copied OID already exists in the new toast table, and if so, assume that it stores the desired value. This is reasonably safe since the only case where we will copy an OID from a previous toast pointer is when toast_insert_or_update was given that toast pointer and so we just pulled the data from the old table; if we got two different values that way then we have big problems anyway. We do have to assume that no other backend is inserting items into the new toast table concurrently, but that's surely safe for CLUSTER and VACUUM FULL. Per bug #6393 from Maxim Boguk. Back-patch to 9.0, same as the previous patch.
2012-01-12 22:40:14 +01:00
* This also tells toast_save_datum() to preserve the toast value
* OIDs, which we want so as not to invalidate toast pointers in
* system catalog caches, and to avoid making multiple copies of a
* single toast value.
*
* Note that we must hold NewHeap open until we are done writing data,
* since the relcache will not guarantee to remember this setting once
* the relation is closed. Also, this technique depends on the fact
* that no one will try to read from the NewHeap until after we've
* finished writing it and swapping the rels --- otherwise they could
Fix CLUSTER/VACUUM FULL for toast values owned by recently-updated rows. In commit 7b0d0e9356963d5c3e4d329a917f5fbb82a2ef05, I made CLUSTER and VACUUM FULL try to preserve toast value OIDs from the original toast table to the new one. However, if we have to copy both live and recently-dead versions of a row that has a toasted column, those versions may well reference the same toast value with the same OID. The patch then led to duplicate-key failures as we tried to insert the toast value twice with the same OID. (The previous behavior was not very desirable either, since it would have silently inserted the same value twice with different OIDs. That wastes space, but what's worse is that the toast values inserted for already-dead heap rows would not be reclaimed by subsequent ordinary VACUUMs, since they go into the new toast table marked live not deleted.) To fix, check if the copied OID already exists in the new toast table, and if so, assume that it stores the desired value. This is reasonably safe since the only case where we will copy an OID from a previous toast pointer is when toast_insert_or_update was given that toast pointer and so we just pulled the data from the old table; if we got two different values that way then we have big problems anyway. We do have to assume that no other backend is inserting items into the new toast table concurrently, but that's surely safe for CLUSTER and VACUUM FULL. Per bug #6393 from Maxim Boguk. Back-patch to 9.0, same as the previous patch.
2012-01-12 22:40:14 +01:00
* follow the toast pointers to the wrong place. (It would actually
* work for values copied over from the old toast table, but not for
* any values that we toast which were previously not toasted.)
*/
NewHeap->rd_toastoid = OldHeap->rd_rel->reltoastrelid;
}
else
*pSwapToastByContent = false;
/*
* Compute xids used to freeze and weed out dead tuples and multixacts.
* Since we're going to rewrite the whole table anyway, there's no reason
* not to be aggressive about this.
*/
memset(&params, 0, sizeof(VacuumParams));
vacuum_get_cutoffs(OldHeap, &params, &cutoffs);
/*
* FreezeXid will become the table's new relfrozenxid, and that mustn't go
* backwards, so take the max.
*/
if (TransactionIdIsValid(OldHeap->rd_rel->relfrozenxid) &&
TransactionIdPrecedes(cutoffs.FreezeLimit,
OldHeap->rd_rel->relfrozenxid))
cutoffs.FreezeLimit = OldHeap->rd_rel->relfrozenxid;
/*
* MultiXactCutoff, similarly, shouldn't go backwards either.
*/
if (MultiXactIdIsValid(OldHeap->rd_rel->relminmxid) &&
MultiXactIdPrecedes(cutoffs.MultiXactCutoff,
OldHeap->rd_rel->relminmxid))
cutoffs.MultiXactCutoff = OldHeap->rd_rel->relminmxid;
/*
* Decide whether to use an indexscan or seqscan-and-optional-sort to scan
* the OldHeap. We know how to use a sort to duplicate the ordering of a
* btree index, and will use seqscan-and-sort for that case if the planner
* tells us it's cheaper. Otherwise, always indexscan if an index is
* provided, else plain seqscan.
*/
if (OldIndex != NULL && OldIndex->rd_rel->relam == BTREE_AM_OID)
use_sort = plan_cluster_use_sort(OIDOldHeap, OIDOldIndex);
else
use_sort = false;
/* Log what we're doing */
if (OldIndex != NULL && !use_sort)
ereport(elevel,
(errmsg("clustering \"%s.%s\" using index scan on \"%s\"",
nspname,
RelationGetRelationName(OldHeap),
RelationGetRelationName(OldIndex))));
else if (use_sort)
ereport(elevel,
(errmsg("clustering \"%s.%s\" using sequential scan and sort",
nspname,
RelationGetRelationName(OldHeap))));
else
ereport(elevel,
(errmsg("vacuuming \"%s.%s\"",
nspname,
RelationGetRelationName(OldHeap))));
/*
* Hand off the actual copying to AM specific function, the generic code
* cannot know how to deal with visibility across AMs. Note that this
* routine is allowed to set FreezeXid / MultiXactCutoff to different
* values (e.g. because the AM doesn't use freezing).
*/
table_relation_copy_for_cluster(OldHeap, NewHeap, OldIndex, use_sort,
cutoffs.OldestXmin, &cutoffs.FreezeLimit,
&cutoffs.MultiXactCutoff,
&num_tuples, &tups_vacuumed,
&tups_recently_dead);
/* return selected values to caller, get set as relfrozenxid/minmxid */
*pFreezeXid = cutoffs.FreezeLimit;
*pCutoffMulti = cutoffs.MultiXactCutoff;
/* Reset rd_toastoid just to be tidy --- it shouldn't be looked at again */
NewHeap->rd_toastoid = InvalidOid;
num_pages = RelationGetNumberOfBlocks(NewHeap);
/* Log what we did */
ereport(elevel,
(errmsg("\"%s.%s\": found %.0f removable, %.0f nonremovable row versions in %u pages",
nspname,
RelationGetRelationName(OldHeap),
tups_vacuumed, num_tuples,
RelationGetNumberOfBlocks(OldHeap)),
errdetail("%.0f dead row versions cannot be removed yet.\n"
"%s.",
tups_recently_dead,
pg_rusage_show(&ru0))));
if (OldIndex != NULL)
index_close(OldIndex, NoLock);
table_close(OldHeap, NoLock);
table_close(NewHeap, NoLock);
/* Update pg_class to reflect the correct values of pages and tuples. */
relRelation = table_open(RelationRelationId, RowExclusiveLock);
reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDNewHeap));
if (!HeapTupleIsValid(reltup))
elog(ERROR, "cache lookup failed for relation %u", OIDNewHeap);
relform = (Form_pg_class) GETSTRUCT(reltup);
relform->relpages = num_pages;
relform->reltuples = num_tuples;
/* Don't update the stats for pg_class. See swap_relation_files. */
if (OIDOldHeap != RelationRelationId)
CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
else
CacheInvalidateRelcacheByTuple(reltup);
/* Clean up. */
heap_freetuple(reltup);
table_close(relRelation, RowExclusiveLock);
/* Make the update visible */
CommandCounterIncrement();
}
/*
* Swap the physical files of two given relations.
*
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
* We swap the physical identity (reltablespace, relfilenumber) while keeping
* the same logical identities of the two relations. relpersistence is also
* swapped, which is critical since it determines where buffers live for each
* relation.
*
* We can swap associated TOAST data in either of two ways: recursively swap
* the physical content of the toast tables (and their indexes), or swap the
* TOAST links in the given relations' pg_class entries. The former is needed
* to manage rewrites of shared catalogs (where we cannot change the pg_class
* links) while the latter is the only way to handle cases in which a toast
* table is added or removed altogether.
*
* Additionally, the first relation is marked with relfrozenxid set to
* frozenXid. It seems a bit ugly to have this here, but the caller would
* have to do it anyway, so having it here saves a heap_update. Note: in
* the swap-toast-links case, we assume we don't need to change the toast
* table's relfrozenxid: the new version of the toast table should already
* have relfrozenxid set to RecentXmin, which is good enough.
*
* Lastly, if r2 and its toast table and toast index (if any) are mapped,
* their OIDs are emitted into mapped_tables[]. This is hacky but beats
* having to look the information up again later in finish_heap_swap.
*/
static void
swap_relation_files(Oid r1, Oid r2, bool target_is_pg_class,
bool swap_toast_by_content,
bool is_internal,
TransactionId frozenXid,
MultiXactId cutoffMulti,
Oid *mapped_tables)
{
Relation relRelation;
HeapTuple reltup1,
reltup2;
Form_pg_class relform1,
relform2;
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
RelFileNumber relfilenumber1,
relfilenumber2;
RelFileNumber swaptemp;
char swptmpchr;
Oid relam1,
relam2;
/* We need writable copies of both pg_class tuples. */
relRelation = table_open(RelationRelationId, RowExclusiveLock);
reltup1 = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(r1));
if (!HeapTupleIsValid(reltup1))
elog(ERROR, "cache lookup failed for relation %u", r1);
relform1 = (Form_pg_class) GETSTRUCT(reltup1);
reltup2 = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(r2));
if (!HeapTupleIsValid(reltup2))
elog(ERROR, "cache lookup failed for relation %u", r2);
relform2 = (Form_pg_class) GETSTRUCT(reltup2);
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
relfilenumber1 = relform1->relfilenode;
relfilenumber2 = relform2->relfilenode;
relam1 = relform1->relam;
relam2 = relform2->relam;
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
if (RelFileNumberIsValid(relfilenumber1) &&
RelFileNumberIsValid(relfilenumber2))
{
/*
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
* Normal non-mapped relations: swap relfilenumbers, reltablespaces,
* relpersistence
*/
Assert(!target_is_pg_class);
swaptemp = relform1->relfilenode;
relform1->relfilenode = relform2->relfilenode;
relform2->relfilenode = swaptemp;
swaptemp = relform1->reltablespace;
relform1->reltablespace = relform2->reltablespace;
relform2->reltablespace = swaptemp;
swaptemp = relform1->relam;
relform1->relam = relform2->relam;
relform2->relam = swaptemp;
swptmpchr = relform1->relpersistence;
relform1->relpersistence = relform2->relpersistence;
relform2->relpersistence = swptmpchr;
/* Also swap toast links, if we're swapping by links */
if (!swap_toast_by_content)
{
swaptemp = relform1->reltoastrelid;
relform1->reltoastrelid = relform2->reltoastrelid;
relform2->reltoastrelid = swaptemp;
}
}
else
{
/*
* Mapped-relation case. Here we have to swap the relation mappings
* instead of modifying the pg_class columns. Both must be mapped.
*/
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
if (RelFileNumberIsValid(relfilenumber1) ||
RelFileNumberIsValid(relfilenumber2))
elog(ERROR, "cannot swap mapped relation \"%s\" with non-mapped relation",
NameStr(relform1->relname));
/*
* We can't change the tablespace nor persistence of a mapped rel, and
* we can't handle toast link swapping for one either, because we must
* not apply any critical changes to its pg_class row. These cases
* should be prevented by upstream permissions tests, so these checks
* are non-user-facing emergency backstop.
*/
if (relform1->reltablespace != relform2->reltablespace)
elog(ERROR, "cannot change tablespace of mapped relation \"%s\"",
NameStr(relform1->relname));
if (relform1->relpersistence != relform2->relpersistence)
elog(ERROR, "cannot change persistence of mapped relation \"%s\"",
NameStr(relform1->relname));
if (relform1->relam != relform2->relam)
elog(ERROR, "cannot change access method of mapped relation \"%s\"",
NameStr(relform1->relname));
if (!swap_toast_by_content &&
(relform1->reltoastrelid || relform2->reltoastrelid))
elog(ERROR, "cannot swap toast by links for mapped relation \"%s\"",
NameStr(relform1->relname));
/*
* Fetch the mappings --- shouldn't fail, but be paranoid
*/
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
relfilenumber1 = RelationMapOidToFilenumber(r1, relform1->relisshared);
if (!RelFileNumberIsValid(relfilenumber1))
elog(ERROR, "could not find relation mapping for relation \"%s\", OID %u",
NameStr(relform1->relname), r1);
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
relfilenumber2 = RelationMapOidToFilenumber(r2, relform2->relisshared);
if (!RelFileNumberIsValid(relfilenumber2))
elog(ERROR, "could not find relation mapping for relation \"%s\", OID %u",
NameStr(relform2->relname), r2);
/*
* Send replacement mappings to relmapper. Note these won't actually
* take effect until CommandCounterIncrement.
*/
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
RelationMapUpdateMap(r1, relfilenumber2, relform1->relisshared, false);
RelationMapUpdateMap(r2, relfilenumber1, relform2->relisshared, false);
/* Pass OIDs of mapped r2 tables back to caller */
*mapped_tables++ = r2;
}
Skip WAL for new relfilenodes, under wal_level=minimal. Until now, only selected bulk operations (e.g. COPY) did this. If a given relfilenode received both a WAL-skipping COPY and a WAL-logged operation (e.g. INSERT), recovery could lose tuples from the COPY. See src/backend/access/transam/README section "Skipping WAL for New RelFileNode" for the new coding rules. Maintainers of table access methods should examine that section. To maintain data durability, just before commit, we choose between an fsync of the relfilenode and copying its contents to WAL. A new GUC, wal_skip_threshold, guides that choice. If this change slows a workload that creates small, permanent relfilenodes under wal_level=minimal, try adjusting wal_skip_threshold. Users setting a timeout on COMMIT may need to adjust that timeout, and log_min_duration_statement analysis will reflect time consumption moving to COMMIT from commands like COPY. Internally, this requires a reliable determination of whether RollbackAndReleaseCurrentSubTransaction() would unlink a relation's current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the specification of rd_createSubid such that the field is zero when a new rel has an old rd_node. Make relcache.c retain entries for certain dropped relations until end of transaction. Bump XLOG_PAGE_MAGIC, since this introduces XLOG_GIST_ASSIGN_LSN. Future servers accept older WAL, so this bump is discretionary. Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert Haas. Heikki Linnakangas and Michael Paquier implemented earlier designs that materially clarified the problem. Reviewed, in earlier designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane, Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout. Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
2020-04-04 21:25:34 +02:00
/*
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
* Recognize that rel1's relfilenumber (swapped from rel2) is new in this
Skip WAL for new relfilenodes, under wal_level=minimal. Until now, only selected bulk operations (e.g. COPY) did this. If a given relfilenode received both a WAL-skipping COPY and a WAL-logged operation (e.g. INSERT), recovery could lose tuples from the COPY. See src/backend/access/transam/README section "Skipping WAL for New RelFileNode" for the new coding rules. Maintainers of table access methods should examine that section. To maintain data durability, just before commit, we choose between an fsync of the relfilenode and copying its contents to WAL. A new GUC, wal_skip_threshold, guides that choice. If this change slows a workload that creates small, permanent relfilenodes under wal_level=minimal, try adjusting wal_skip_threshold. Users setting a timeout on COMMIT may need to adjust that timeout, and log_min_duration_statement analysis will reflect time consumption moving to COMMIT from commands like COPY. Internally, this requires a reliable determination of whether RollbackAndReleaseCurrentSubTransaction() would unlink a relation's current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the specification of rd_createSubid such that the field is zero when a new rel has an old rd_node. Make relcache.c retain entries for certain dropped relations until end of transaction. Bump XLOG_PAGE_MAGIC, since this introduces XLOG_GIST_ASSIGN_LSN. Future servers accept older WAL, so this bump is discretionary. Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert Haas. Heikki Linnakangas and Michael Paquier implemented earlier designs that materially clarified the problem. Reviewed, in earlier designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane, Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout. Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
2020-04-04 21:25:34 +02:00
* subtransaction. The rel2 storage (swapped from rel1) may or may not be
* new.
*/
{
Relation rel1,
rel2;
rel1 = relation_open(r1, NoLock);
rel2 = relation_open(r2, NoLock);
rel2->rd_createSubid = rel1->rd_createSubid;
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
rel2->rd_newRelfilelocatorSubid = rel1->rd_newRelfilelocatorSubid;
rel2->rd_firstRelfilelocatorSubid = rel1->rd_firstRelfilelocatorSubid;
RelationAssumeNewRelfilelocator(rel1);
Skip WAL for new relfilenodes, under wal_level=minimal. Until now, only selected bulk operations (e.g. COPY) did this. If a given relfilenode received both a WAL-skipping COPY and a WAL-logged operation (e.g. INSERT), recovery could lose tuples from the COPY. See src/backend/access/transam/README section "Skipping WAL for New RelFileNode" for the new coding rules. Maintainers of table access methods should examine that section. To maintain data durability, just before commit, we choose between an fsync of the relfilenode and copying its contents to WAL. A new GUC, wal_skip_threshold, guides that choice. If this change slows a workload that creates small, permanent relfilenodes under wal_level=minimal, try adjusting wal_skip_threshold. Users setting a timeout on COMMIT may need to adjust that timeout, and log_min_duration_statement analysis will reflect time consumption moving to COMMIT from commands like COPY. Internally, this requires a reliable determination of whether RollbackAndReleaseCurrentSubTransaction() would unlink a relation's current relfilenode. Introduce rd_firstRelfilenodeSubid. Amend the specification of rd_createSubid such that the field is zero when a new rel has an old rd_node. Make relcache.c retain entries for certain dropped relations until end of transaction. Bump XLOG_PAGE_MAGIC, since this introduces XLOG_GIST_ASSIGN_LSN. Future servers accept older WAL, so this bump is discretionary. Kyotaro Horiguchi, reviewed (in earlier, similar versions) by Robert Haas. Heikki Linnakangas and Michael Paquier implemented earlier designs that materially clarified the problem. Reviewed, in earlier designs, by Andrew Dunstan, Andres Freund, Alvaro Herrera, Tom Lane, Fujii Masao, and Simon Riggs. Reported by Martijn van Oosterhout. Discussion: https://postgr.es/m/20150702220524.GA9392@svana.org
2020-04-04 21:25:34 +02:00
relation_close(rel1, NoLock);
relation_close(rel2, NoLock);
}
/*
* In the case of a shared catalog, these next few steps will only affect
* our own database's pg_class row; but that's okay, because they are all
* noncritical updates. That's also an important fact for the case of a
* mapped catalog, because it's possible that we'll commit the map change
* and then fail to commit the pg_class update.
*/
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
/* set rel1's frozen Xid and minimum MultiXid */
if (relform1->relkind != RELKIND_INDEX)
{
Assert(!TransactionIdIsValid(frozenXid) ||
TransactionIdIsNormal(frozenXid));
relform1->relfrozenxid = frozenXid;
relform1->relminmxid = cutoffMulti;
}
/* swap size statistics too, since new rel has freshly-updated stats */
{
int32 swap_pages;
float4 swap_tuples;
int32 swap_allvisible;
swap_pages = relform1->relpages;
relform1->relpages = relform2->relpages;
relform2->relpages = swap_pages;
swap_tuples = relform1->reltuples;
relform1->reltuples = relform2->reltuples;
relform2->reltuples = swap_tuples;
swap_allvisible = relform1->relallvisible;
relform1->relallvisible = relform2->relallvisible;
relform2->relallvisible = swap_allvisible;
}
/*
* Update the tuples in pg_class --- unless the target relation of the
* swap is pg_class itself. In that case, there is zero point in making
* changes because we'd be updating the old data that we're about to throw
* away. Because the real work being done here for a mapped relation is
* just to change the relation map settings, it's all right to not update
* the pg_class rows in this case. The most important changes will instead
* performed later, in finish_heap_swap() itself.
*/
if (!target_is_pg_class)
{
CatalogIndexState indstate;
indstate = CatalogOpenIndexes(relRelation);
CatalogTupleUpdateWithInfo(relRelation, &reltup1->t_self, reltup1,
indstate);
CatalogTupleUpdateWithInfo(relRelation, &reltup2->t_self, reltup2,
indstate);
CatalogCloseIndexes(indstate);
}
else
{
/* no update ... but we do still need relcache inval */
CacheInvalidateRelcacheByTuple(reltup1);
CacheInvalidateRelcacheByTuple(reltup2);
}
/*
* Now that pg_class has been updated with its relevant information for
* the swap, update the dependency of the relations to point to their new
* table AM, if it has changed.
*/
if (relam1 != relam2)
{
if (changeDependencyFor(RelationRelationId,
r1,
AccessMethodRelationId,
relam1,
relam2) != 1)
elog(ERROR, "could not change access method dependency for relation \"%s.%s\"",
get_namespace_name(get_rel_namespace(r1)),
get_rel_name(r1));
if (changeDependencyFor(RelationRelationId,
r2,
AccessMethodRelationId,
relam2,
relam1) != 1)
elog(ERROR, "could not change access method dependency for relation \"%s.%s\"",
get_namespace_name(get_rel_namespace(r2)),
get_rel_name(r2));
}
/*
* Post alter hook for modified relations. The change to r2 is always
* internal, but r1 depends on the invocation context.
*/
InvokeObjectPostAlterHookArg(RelationRelationId, r1, 0,
InvalidOid, is_internal);
InvokeObjectPostAlterHookArg(RelationRelationId, r2, 0,
InvalidOid, true);
/*
* If we have toast tables associated with the relations being swapped,
* deal with them too.
*/
if (relform1->reltoastrelid || relform2->reltoastrelid)
{
if (swap_toast_by_content)
{
if (relform1->reltoastrelid && relform2->reltoastrelid)
{
/* Recursively swap the contents of the toast tables */
swap_relation_files(relform1->reltoastrelid,
relform2->reltoastrelid,
target_is_pg_class,
swap_toast_by_content,
is_internal,
frozenXid,
cutoffMulti,
mapped_tables);
}
else
{
/* caller messed up */
elog(ERROR, "cannot swap toast files by content when there's only one");
}
}
else
{
/*
* We swapped the ownership links, so we need to change dependency
* data to match.
*
* NOTE: it is possible that only one table has a toast table.
*
* NOTE: at present, a TOAST table's only dependency is the one on
* its owning table. If more are ever created, we'd need to use
* something more selective than deleteDependencyRecordsFor() to
* get rid of just the link we want.
*/
ObjectAddress baseobject,
toastobject;
long count;
/*
* We disallow this case for system catalogs, to avoid the
* possibility that the catalog we're rebuilding is one of the
* ones the dependency changes would change. It's too late to be
* making any data changes to the target catalog.
*/
if (IsSystemClass(r1, relform1))
elog(ERROR, "cannot swap toast files by links for system catalogs");
/* Delete old dependencies */
if (relform1->reltoastrelid)
{
count = deleteDependencyRecordsFor(RelationRelationId,
relform1->reltoastrelid,
false);
if (count != 1)
elog(ERROR, "expected one dependency record for TOAST table, found %ld",
count);
}
if (relform2->reltoastrelid)
{
count = deleteDependencyRecordsFor(RelationRelationId,
relform2->reltoastrelid,
false);
if (count != 1)
elog(ERROR, "expected one dependency record for TOAST table, found %ld",
count);
}
/* Register new dependencies */
baseobject.classId = RelationRelationId;
baseobject.objectSubId = 0;
toastobject.classId = RelationRelationId;
toastobject.objectSubId = 0;
if (relform1->reltoastrelid)
{
baseobject.objectId = r1;
toastobject.objectId = relform1->reltoastrelid;
recordDependencyOn(&toastobject, &baseobject,
DEPENDENCY_INTERNAL);
}
if (relform2->reltoastrelid)
{
baseobject.objectId = r2;
toastobject.objectId = relform2->reltoastrelid;
recordDependencyOn(&toastobject, &baseobject,
DEPENDENCY_INTERNAL);
}
}
}
/*
* If we're swapping two toast tables by content, do the same for their
* valid index. The swap can actually be safely done only if the relations
* have indexes.
*/
if (swap_toast_by_content &&
relform1->relkind == RELKIND_TOASTVALUE &&
relform2->relkind == RELKIND_TOASTVALUE)
{
Oid toastIndex1,
toastIndex2;
/* Get valid index for each relation */
toastIndex1 = toast_get_valid_index(r1,
AccessExclusiveLock);
toastIndex2 = toast_get_valid_index(r2,
AccessExclusiveLock);
swap_relation_files(toastIndex1,
toastIndex2,
target_is_pg_class,
swap_toast_by_content,
is_internal,
InvalidTransactionId,
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
InvalidMultiXactId,
mapped_tables);
}
/* Clean up. */
heap_freetuple(reltup1);
heap_freetuple(reltup2);
table_close(relRelation, RowExclusiveLock);
}
/*
* Remove the transient table that was built by make_new_heap, and finish
* cleaning up (including rebuilding all indexes on the old heap).
*/
void
finish_heap_swap(Oid OIDOldHeap, Oid OIDNewHeap,
bool is_system_catalog,
bool swap_toast_by_content,
bool check_constraints,
bool is_internal,
Improve concurrency of foreign key locking This patch introduces two additional lock modes for tuples: "SELECT FOR KEY SHARE" and "SELECT FOR NO KEY UPDATE". These don't block each other, in contrast with already existing "SELECT FOR SHARE" and "SELECT FOR UPDATE". UPDATE commands that do not modify the values stored in the columns that are part of the key of the tuple now grab a SELECT FOR NO KEY UPDATE lock on the tuple, allowing them to proceed concurrently with tuple locks of the FOR KEY SHARE variety. Foreign key triggers now use FOR KEY SHARE instead of FOR SHARE; this means the concurrency improvement applies to them, which is the whole point of this patch. The added tuple lock semantics require some rejiggering of the multixact module, so that the locking level that each transaction is holding can be stored alongside its Xid. Also, multixacts now need to persist across server restarts and crashes, because they can now represent not only tuple locks, but also tuple updates. This means we need more careful tracking of lifetime of pg_multixact SLRU files; since they now persist longer, we require more infrastructure to figure out when they can be removed. pg_upgrade also needs to be careful to copy pg_multixact files over from the old server to the new, or at least part of multixact.c state, depending on the versions of the old and new servers. Tuple time qualification rules (HeapTupleSatisfies routines) need to be careful not to consider tuples with the "is multi" infomask bit set as being only locked; they might need to look up MultiXact values (i.e. possibly do pg_multixact I/O) to find out the Xid that updated a tuple, whereas they previously were assured to only use information readily available from the tuple header. This is considered acceptable, because the extra I/O would involve cases that would previously cause some commands to block waiting for concurrent transactions to finish. Another important change is the fact that locking tuples that have previously been updated causes the future versions to be marked as locked, too; this is essential for correctness of foreign key checks. This causes additional WAL-logging, also (there was previously a single WAL record for a locked tuple; now there are as many as updated copies of the tuple there exist.) With all this in place, contention related to tuples being checked by foreign key rules should be much reduced. As a bonus, the old behavior that a subtransaction grabbing a stronger tuple lock than the parent (sub)transaction held on a given tuple and later aborting caused the weaker lock to be lost, has been fixed. Many new spec files were added for isolation tester framework, to ensure overall behavior is sane. There's probably room for several more tests. There were several reviewers of this patch; in particular, Noah Misch and Andres Freund spent considerable time in it. Original idea for the patch came from Simon Riggs, after a problem report by Joel Jacobson. Most code is from me, with contributions from Marti Raudsepp, Alexander Shulgin, Noah Misch and Andres Freund. This patch was discussed in several pgsql-hackers threads; the most important start at the following message-ids: AANLkTimo9XVcEzfiBR-ut3KVNDkjm2Vxh+t8kAmWjPuv@mail.gmail.com 1290721684-sup-3951@alvh.no-ip.org 1294953201-sup-2099@alvh.no-ip.org 1320343602-sup-2290@alvh.no-ip.org 1339690386-sup-8927@alvh.no-ip.org 4FE5FF020200002500048A3D@gw.wicourts.gov 4FEAB90A0200002500048B7D@gw.wicourts.gov
2013-01-23 16:04:59 +01:00
TransactionId frozenXid,
MultiXactId cutoffMulti,
char newrelpersistence)
{
ObjectAddress object;
Oid mapped_tables[4];
int reindex_flags;
ReindexParams reindex_params = {0};
int i;
/* Report that we are now swapping relation files */
pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE,
PROGRESS_CLUSTER_PHASE_SWAP_REL_FILES);
/* Zero out possible results from swapped_relation_files */
memset(mapped_tables, 0, sizeof(mapped_tables));
/*
* Swap the contents of the heap relations (including any toast tables).
* Also set old heap's relfrozenxid to frozenXid.
*/
swap_relation_files(OIDOldHeap, OIDNewHeap,
(OIDOldHeap == RelationRelationId),
swap_toast_by_content, is_internal,
frozenXid, cutoffMulti, mapped_tables);
/*
* If it's a system catalog, queue a sinval message to flush all catcaches
* on the catalog when we reach CommandCounterIncrement.
*/
if (is_system_catalog)
CacheInvalidateCatalog(OIDOldHeap);
/*
* Rebuild each index on the relation (but not the toast table, which is
* all-new at this point). It is important to do this before the DROP
* step because if we are processing a system catalog that will be used
* during DROP, we want to have its indexes available. There is no
* advantage to the other order anyway because this is all transactional,
* so no chance to reclaim disk space before commit. We do not need a
* final CommandCounterIncrement() because reindex_relation does it.
*
* Note: because index_build is called via reindex_relation, it will never
* set indcheckxmin true for the indexes. This is OK even though in some
* sense we are building new indexes rather than rebuilding existing ones,
* because the new heap won't contain any HOT chains at all, let alone
* broken ones, so it can't be necessary to set indcheckxmin.
*/
reindex_flags = REINDEX_REL_SUPPRESS_INDEX_USE;
if (check_constraints)
reindex_flags |= REINDEX_REL_CHECK_CONSTRAINTS;
/*
* Ensure that the indexes have the same persistence as the parent
* relation.
*/
if (newrelpersistence == RELPERSISTENCE_UNLOGGED)
reindex_flags |= REINDEX_REL_FORCE_INDEXES_UNLOGGED;
else if (newrelpersistence == RELPERSISTENCE_PERMANENT)
reindex_flags |= REINDEX_REL_FORCE_INDEXES_PERMANENT;
/* Report that we are now reindexing relations */
pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE,
PROGRESS_CLUSTER_PHASE_REBUILD_INDEX);
reindex_relation(NULL, OIDOldHeap, reindex_flags, &reindex_params);
/* Report that we are now doing clean up */
pgstat_progress_update_param(PROGRESS_CLUSTER_PHASE,
PROGRESS_CLUSTER_PHASE_FINAL_CLEANUP);
/*
* If the relation being rebuilt is pg_class, swap_relation_files()
* couldn't update pg_class's own pg_class entry (check comments in
* swap_relation_files()), thus relfrozenxid was not updated. That's
* annoying because a potential reason for doing a VACUUM FULL is a
* imminent or actual anti-wraparound shutdown. So, now that we can
* access the new relation using its indices, update relfrozenxid.
* pg_class doesn't have a toast relation, so we don't need to update the
* corresponding toast relation. Not that there's little point moving all
* relfrozenxid updates here since swap_relation_files() needs to write to
* pg_class for non-mapped relations anyway.
*/
if (OIDOldHeap == RelationRelationId)
{
Relation relRelation;
HeapTuple reltup;
Form_pg_class relform;
relRelation = table_open(RelationRelationId, RowExclusiveLock);
reltup = SearchSysCacheCopy1(RELOID, ObjectIdGetDatum(OIDOldHeap));
if (!HeapTupleIsValid(reltup))
elog(ERROR, "cache lookup failed for relation %u", OIDOldHeap);
relform = (Form_pg_class) GETSTRUCT(reltup);
relform->relfrozenxid = frozenXid;
relform->relminmxid = cutoffMulti;
CatalogTupleUpdate(relRelation, &reltup->t_self, reltup);
table_close(relRelation, RowExclusiveLock);
}
Change internal RelFileNode references to RelFileNumber or RelFileLocator. We have been using the term RelFileNode to refer to either (1) the integer that is used to name the sequence of files for a certain relation within the directory set aside for that tablespace/database combination; or (2) that value plus the OIDs of the tablespace and database; or occasionally (3) the whole series of files created for a relation based on those values. Using the same name for more than one thing is confusing. Replace RelFileNode with RelFileNumber when we're talking about just the single number, i.e. (1) from above, and with RelFileLocator when we're talking about all the things that are needed to locate a relation's files on disk, i.e. (2) from above. In the places where we refer to (3) as a relfilenode, instead refer to "relation storage". Since there is a ton of SQL code in the world that knows about pg_class.relfilenode, don't change the name of that column, or of other SQL-facing things that derive their name from it. On the other hand, do adjust closely-related internal terminology. For example, the structure member names dbNode and spcNode appear to be derived from the fact that the structure itself was called RelFileNode, so change those to dbOid and spcOid. Likewise, various variables with names like rnode and relnode get renamed appropriately, according to how they're being used in context. Hopefully, this is clearer than before. It is also preparation for future patches that intend to widen the relfilenumber fields from its current width of 32 bits. Variables that store a relfilenumber are now declared as type RelFileNumber rather than type Oid; right now, these are the same, but that can now more easily be changed. Dilip Kumar, per an idea from me. Reviewed also by Andres Freund. I fixed some whitespace issues, changed a couple of words in a comment, and made one other minor correction. Discussion: http://postgr.es/m/CA+TgmoamOtXbVAQf9hWFzonUo6bhhjS6toZQd7HZ-pmojtAmag@mail.gmail.com Discussion: http://postgr.es/m/CA+Tgmobp7+7kmi4gkq7Y+4AM9fTvL+O1oQ4-5gFTT+6Ng-dQ=g@mail.gmail.com Discussion: http://postgr.es/m/CAFiTN-vTe79M8uDH1yprOU64MNFE+R3ODRuA+JWf27JbhY4hJw@mail.gmail.com
2022-07-06 17:39:09 +02:00
/* Destroy new heap with old filenumber */
object.classId = RelationRelationId;
object.objectId = OIDNewHeap;
object.objectSubId = 0;
/*
* The new relation is local to our transaction and we know nothing
* depends on it, so DROP_RESTRICT should be OK.
*/
performDeletion(&object, DROP_RESTRICT, PERFORM_DELETION_INTERNAL);
/* performDeletion does CommandCounterIncrement at end */
/*
* Now we must remove any relation mapping entries that we set up for the
* transient table, as well as its toast table and toast index if any. If
* we fail to do this before commit, the relmapper will complain about new
* permanent map entries being added post-bootstrap.
*/
for (i = 0; OidIsValid(mapped_tables[i]); i++)
RelationMapRemoveMapping(mapped_tables[i]);
/*
* At this point, everything is kosher except that, if we did toast swap
* by links, the toast table's name corresponds to the transient table.
* The name is irrelevant to the backend because it's referenced by OID,
* but users looking at the catalogs could be confused. Rename it to
* prevent this problem.
*
* Note no lock required on the relation, because we already hold an
* exclusive lock on it.
*/
if (!swap_toast_by_content)
{
Relation newrel;
newrel = table_open(OIDOldHeap, NoLock);
if (OidIsValid(newrel->rd_rel->reltoastrelid))
{
Oid toastidx;
char NewToastName[NAMEDATALEN];
/* Get the associated valid index to be renamed */
toastidx = toast_get_valid_index(newrel->rd_rel->reltoastrelid,
NoLock);
/* rename the toast table ... */
snprintf(NewToastName, NAMEDATALEN, "pg_toast_%u",
OIDOldHeap);
RenameRelationInternal(newrel->rd_rel->reltoastrelid,
Lower lock level for renaming indexes Change lock level for renaming index (either ALTER INDEX or implicitly via some other commands) from AccessExclusiveLock to ShareUpdateExclusiveLock. One reason we need a strong lock for relation renaming is that the name change causes a rebuild of the relcache entry. Concurrent sessions that have the relation open might not be able to handle the relcache entry changing underneath them. Therefore, we need to lock the relation in a way that no one can have the relation open concurrently. But for indexes, the relcache handles reloads specially in RelationReloadIndexInfo() in a way that keeps changes in the relcache entry to a minimum. As long as no one keeps pointers to rd_amcache and rd_options around across possible relcache flushes, which is the case, this ought to be safe. We also want to use a self-exclusive lock for correctness, so that concurrent DDL doesn't overwrite the rename if they start updating while still seeing the old version. Therefore, we use ShareUpdateExclusiveLock, which is already used by other DDL commands that want to operate in a concurrent manner. The reason this is interesting at all is that renaming an index is a typical part of a concurrent reindexing workflow (CREATE INDEX CONCURRENTLY new + DROP INDEX CONCURRENTLY old + rename back). And indeed a future built-in REINDEX CONCURRENTLY might rely on the ability to do concurrent renames as well. Reviewed-by: Andrey Klychkov <aaklychkov@mail.ru> Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/1531767486.432607658@f357.i.mail.ru
2018-10-25 09:33:17 +02:00
NewToastName, true, false);
/* ... and its valid index too. */
snprintf(NewToastName, NAMEDATALEN, "pg_toast_%u_index",
OIDOldHeap);
RenameRelationInternal(toastidx,
Lower lock level for renaming indexes Change lock level for renaming index (either ALTER INDEX or implicitly via some other commands) from AccessExclusiveLock to ShareUpdateExclusiveLock. One reason we need a strong lock for relation renaming is that the name change causes a rebuild of the relcache entry. Concurrent sessions that have the relation open might not be able to handle the relcache entry changing underneath them. Therefore, we need to lock the relation in a way that no one can have the relation open concurrently. But for indexes, the relcache handles reloads specially in RelationReloadIndexInfo() in a way that keeps changes in the relcache entry to a minimum. As long as no one keeps pointers to rd_amcache and rd_options around across possible relcache flushes, which is the case, this ought to be safe. We also want to use a self-exclusive lock for correctness, so that concurrent DDL doesn't overwrite the rename if they start updating while still seeing the old version. Therefore, we use ShareUpdateExclusiveLock, which is already used by other DDL commands that want to operate in a concurrent manner. The reason this is interesting at all is that renaming an index is a typical part of a concurrent reindexing workflow (CREATE INDEX CONCURRENTLY new + DROP INDEX CONCURRENTLY old + rename back). And indeed a future built-in REINDEX CONCURRENTLY might rely on the ability to do concurrent renames as well. Reviewed-by: Andrey Klychkov <aaklychkov@mail.ru> Reviewed-by: Fabrízio de Royes Mello <fabriziomello@gmail.com> Discussion: https://www.postgresql.org/message-id/flat/1531767486.432607658@f357.i.mail.ru
2018-10-25 09:33:17 +02:00
NewToastName, true, true);
/*
* Reset the relrewrite for the toast. The command-counter
* increment is required here as we are about to update the tuple
* that is updated as part of RenameRelationInternal.
*/
CommandCounterIncrement();
ResetRelRewrite(newrel->rd_rel->reltoastrelid);
}
relation_close(newrel, NoLock);
}
/* if it's not a catalog table, clear any missing attribute settings */
if (!is_system_catalog)
{
Relation newrel;
newrel = table_open(OIDOldHeap, NoLock);
RelationClearMissing(newrel);
relation_close(newrel, NoLock);
}
}
/*
* Get a list of tables that the current user has privileges on and
* have indisclustered set. Return the list in a List * of RelToCluster
* (stored in the specified memory context), each one giving the tableOid
* and the indexOid on which the table is already clustered.
*/
static List *
get_tables_to_cluster(MemoryContext cluster_context)
{
Relation indRelation;
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
TableScanDesc scan;
ScanKeyData entry;
HeapTuple indexTuple;
Form_pg_index index;
MemoryContext old_context;
List *rtcs = NIL;
/*
* Get all indexes that have indisclustered set and that the current user
* has the appropriate privileges for.
*/
indRelation = table_open(IndexRelationId, AccessShareLock);
ScanKeyInit(&entry,
Anum_pg_index_indisclustered,
BTEqualStrategyNumber, F_BOOLEQ,
BoolGetDatum(true));
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
scan = table_beginscan_catalog(indRelation, 1, &entry);
while ((indexTuple = heap_getnext(scan, ForwardScanDirection)) != NULL)
{
RelToCluster *rtc;
index = (Form_pg_index) GETSTRUCT(indexTuple);
if (!cluster_is_permitted_for_relation(index->indrelid, GetUserId()))
continue;
/* Use a permanent memory context for the result list */
old_context = MemoryContextSwitchTo(cluster_context);
rtc = (RelToCluster *) palloc(sizeof(RelToCluster));
rtc->tableOid = index->indrelid;
rtc->indexOid = index->indexrelid;
rtcs = lappend(rtcs, rtc);
MemoryContextSwitchTo(old_context);
}
tableam: Add and use scan APIs. Too allow table accesses to be not directly dependent on heap, several new abstractions are needed. Specifically: 1) Heap scans need to be generalized into table scans. Do this by introducing TableScanDesc, which will be the "base class" for individual AMs. This contains the AM independent fields from HeapScanDesc. The previous heap_{beginscan,rescan,endscan} et al. have been replaced with a table_ version. There's no direct replacement for heap_getnext(), as that returned a HeapTuple, which is undesirable for a other AMs. Instead there's table_scan_getnextslot(). But note that heap_getnext() lives on, it's still used widely to access catalog tables. This is achieved by new scan_begin, scan_end, scan_rescan, scan_getnextslot callbacks. 2) The portion of parallel scans that's shared between backends need to be able to do so without the user doing per-AM work. To achieve that new parallelscan_{estimate, initialize, reinitialize} callbacks are introduced, which operate on a new ParallelTableScanDesc, which again can be subclassed by AMs. As it is likely that several AMs are going to be block oriented, block oriented callbacks that can be shared between such AMs are provided and used by heap. table_block_parallelscan_{estimate, intiialize, reinitialize} as callbacks, and table_block_parallelscan_{nextpage, init} for use in AMs. These operate on a ParallelBlockTableScanDesc. 3) Index scans need to be able to access tables to return a tuple, and there needs to be state across individual accesses to the heap to store state like buffers. That's now handled by introducing a sort-of-scan IndexFetchTable, which again is intended to be subclassed by individual AMs (for heap IndexFetchHeap). The relevant callbacks for an AM are index_fetch_{end, begin, reset} to create the necessary state, and index_fetch_tuple to retrieve an indexed tuple. Note that index_fetch_tuple implementations need to be smarter than just blindly fetching the tuples for AMs that have optimizations similar to heap's HOT - the currently alive tuple in the update chain needs to be fetched if appropriate. Similar to table_scan_getnextslot(), it's undesirable to continue to return HeapTuples. Thus index_fetch_heap (might want to rename that later) now accepts a slot as an argument. Core code doesn't have a lot of call sites performing index scans without going through the systable_* API (in contrast to loads of heap_getnext calls and working directly with HeapTuples). Index scans now store the result of a search in IndexScanDesc->xs_heaptid, rather than xs_ctup->t_self. As the target is not generally a HeapTuple anymore that seems cleaner. To be able to sensible adapt code to use the above, two further callbacks have been introduced: a) slot_callbacks returns a TupleTableSlotOps* suitable for creating slots capable of holding a tuple of the AMs type. table_slot_callbacks() and table_slot_create() are based upon that, but have additional logic to deal with views, foreign tables, etc. While this change could have been done separately, nearly all the call sites that needed to be adapted for the rest of this commit also would have been needed to be adapted for table_slot_callbacks(), making separation not worthwhile. b) tuple_satisfies_snapshot checks whether the tuple in a slot is currently visible according to a snapshot. That's required as a few places now don't have a buffer + HeapTuple around, but a slot (which in heap's case internally has that information). Additionally a few infrastructure changes were needed: I) SysScanDesc, as used by systable_{beginscan, getnext} et al. now internally uses a slot to keep track of tuples. While systable_getnext() still returns HeapTuples, and will so for the foreseeable future, the index API (see 1) above) now only deals with slots. The remainder, and largest part, of this commit is then adjusting all scans in postgres to use the new APIs. Author: Andres Freund, Haribabu Kommi, Alvaro Herrera Discussion: https://postgr.es/m/20180703070645.wchpu5muyto5n647@alap3.anarazel.de https://postgr.es/m/20160812231527.GA690404@alvherre.pgsql
2019-03-11 20:46:41 +01:00
table_endscan(scan);
relation_close(indRelation, AccessShareLock);
return rtcs;
}
/*
* Given an index on a partitioned table, return a list of RelToCluster for
* all the children leaves tables/indexes.
*
* Like expand_vacuum_rel, but here caller must hold AccessExclusiveLock
* on the table containing the index.
*/
static List *
get_tables_to_cluster_partitioned(MemoryContext cluster_context, Oid indexOid)
{
List *inhoids;
ListCell *lc;
List *rtcs = NIL;
MemoryContext old_context;
/* Do not lock the children until they're processed */
inhoids = find_all_inheritors(indexOid, NoLock, NULL);
foreach(lc, inhoids)
{
Oid indexrelid = lfirst_oid(lc);
Oid relid = IndexGetRelation(indexrelid, false);
RelToCluster *rtc;
/* consider only leaf indexes */
if (get_rel_relkind(indexrelid) != RELKIND_INDEX)
continue;
/*
* It's possible that the user does not have privileges to CLUSTER the
* leaf partition despite having such privileges on the partitioned
* table. We skip any partitions which the user is not permitted to
* CLUSTER.
*/
if (!cluster_is_permitted_for_relation(relid, GetUserId()))
continue;
/* Use a permanent memory context for the result list */
old_context = MemoryContextSwitchTo(cluster_context);
rtc = (RelToCluster *) palloc(sizeof(RelToCluster));
rtc->tableOid = relid;
rtc->indexOid = indexrelid;
rtcs = lappend(rtcs, rtc);
MemoryContextSwitchTo(old_context);
}
return rtcs;
}
/*
* Return whether userid has privileges to CLUSTER relid. If not, this
* function emits a WARNING.
*/
static bool
cluster_is_permitted_for_relation(Oid relid, Oid userid)
{
if (pg_class_aclcheck(relid, userid, ACL_MAINTAIN) == ACLCHECK_OK)
return true;
ereport(WARNING,
(errmsg("permission denied to cluster \"%s\", skipping it",
get_rel_name(relid))));
return false;
}