postgresql/src/backend/catalog/indexing.c

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/*-------------------------------------------------------------------------
*
* indexing.c
* This file contains routines to support indexes defined on system
* catalogs.
*
* Portions Copyright (c) 1996-2018, PostgreSQL Global Development Group
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
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* src/backend/catalog/indexing.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "access/htup_details.h"
#include "catalog/index.h"
#include "catalog/indexing.h"
#include "executor/executor.h"
#include "utils/rel.h"
/*
* CatalogOpenIndexes - open the indexes on a system catalog.
*
* When inserting or updating tuples in a system catalog, call this
* to prepare to update the indexes for the catalog.
*
* In the current implementation, we share code for opening/closing the
* indexes with execUtils.c. But we do not use ExecInsertIndexTuples,
* because we don't want to create an EState. This implies that we
* do not support partial or expressional indexes on system catalogs,
* nor can we support generalized exclusion constraints.
* This could be fixed with localized changes here if we wanted to pay
* the extra overhead of building an EState.
*/
CatalogIndexState
CatalogOpenIndexes(Relation heapRel)
{
ResultRelInfo *resultRelInfo;
resultRelInfo = makeNode(ResultRelInfo);
resultRelInfo->ri_RangeTableIndex = 0; /* dummy */
resultRelInfo->ri_RelationDesc = heapRel;
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resultRelInfo->ri_TrigDesc = NULL; /* we don't fire triggers */
Add support for INSERT ... ON CONFLICT DO NOTHING/UPDATE. The newly added ON CONFLICT clause allows to specify an alternative to raising a unique or exclusion constraint violation error when inserting. ON CONFLICT refers to constraints that can either be specified using a inference clause (by specifying the columns of a unique constraint) or by naming a unique or exclusion constraint. DO NOTHING avoids the constraint violation, without touching the pre-existing row. DO UPDATE SET ... [WHERE ...] updates the pre-existing tuple, and has access to both the tuple proposed for insertion and the existing tuple; the optional WHERE clause can be used to prevent an update from being executed. The UPDATE SET and WHERE clauses have access to the tuple proposed for insertion using the "magic" EXCLUDED alias, and to the pre-existing tuple using the table name or its alias. This feature is often referred to as upsert. This is implemented using a new infrastructure called "speculative insertion". It is an optimistic variant of regular insertion that first does a pre-check for existing tuples and then attempts an insert. If a violating tuple was inserted concurrently, the speculatively inserted tuple is deleted and a new attempt is made. If the pre-check finds a matching tuple the alternative DO NOTHING or DO UPDATE action is taken. If the insertion succeeds without detecting a conflict, the tuple is deemed inserted. To handle the possible ambiguity between the excluded alias and a table named excluded, and for convenience with long relation names, INSERT INTO now can alias its target table. Bumps catversion as stored rules change. Author: Peter Geoghegan, with significant contributions from Heikki Linnakangas and Andres Freund. Testing infrastructure by Jeff Janes. Reviewed-By: Heikki Linnakangas, Andres Freund, Robert Haas, Simon Riggs, Dean Rasheed, Stephen Frost and many others.
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ExecOpenIndices(resultRelInfo, false);
return resultRelInfo;
}
/*
* CatalogCloseIndexes - clean up resources allocated by CatalogOpenIndexes
*/
void
CatalogCloseIndexes(CatalogIndexState indstate)
{
ExecCloseIndices(indstate);
pfree(indstate);
}
/*
* CatalogIndexInsert - insert index entries for one catalog tuple
*
* This should be called for each inserted or updated catalog tuple.
*
* This is effectively a cut-down version of ExecInsertIndexTuples.
*/
static void
CatalogIndexInsert(CatalogIndexState indstate, HeapTuple heapTuple)
{
int i;
int numIndexes;
RelationPtr relationDescs;
Relation heapRelation;
TupleTableSlot *slot;
IndexInfo **indexInfoArray;
Datum values[INDEX_MAX_KEYS];
bool isnull[INDEX_MAX_KEYS];
/* HOT update does not require index inserts */
if (HeapTupleIsHeapOnly(heapTuple))
return;
/*
* Get information from the state structure. Fall out if nothing to do.
*/
numIndexes = indstate->ri_NumIndices;
if (numIndexes == 0)
return;
relationDescs = indstate->ri_IndexRelationDescs;
indexInfoArray = indstate->ri_IndexRelationInfo;
heapRelation = indstate->ri_RelationDesc;
/* Need a slot to hold the tuple being examined */
Introduce notion of different types of slots (without implementing them). Upcoming work intends to allow pluggable ways to introduce new ways of storing table data. Accessing those table access methods from the executor requires TupleTableSlots to be carry tuples in the native format of such storage methods; otherwise there'll be a significant conversion overhead. Different access methods will require different data to store tuples efficiently (just like virtual, minimal, heap already require fields in TupleTableSlot). To allow that without requiring additional pointer indirections, we want to have different structs (embedding TupleTableSlot) for different types of slots. Thus different types of slots are needed, which requires adapting creators of slots. The slot that most efficiently can represent a type of tuple in an executor node will often depend on the type of slot a child node uses. Therefore we need to track the type of slot is returned by nodes, so parent slots can create slots based on that. Relatedly, JIT compilation of tuple deforming needs to know which type of slot a certain expression refers to, so it can create an appropriate deforming function for the type of tuple in the slot. But not all nodes will only return one type of slot, e.g. an append node will potentially return different types of slots for each of its subplans. Therefore add function that allows to query the type of a node's result slot, and whether it'll always be the same type (whether it's fixed). This can be queried using ExecGetResultSlotOps(). The scan, result, inner, outer type of slots are automatically inferred from ExecInitScanTupleSlot(), ExecInitResultSlot(), left/right subtrees respectively. If that's not correct for a node, that can be overwritten using new fields in PlanState. This commit does not introduce the actually abstracted implementation of different kind of TupleTableSlots, that will be left for a followup commit. The different types of slots introduced will, for now, still use the same backing implementation. While this already partially invalidates the big comment in tuptable.h, it seems to make more sense to update it later, when the different TupleTableSlot implementations actually exist. Author: Ashutosh Bapat and Andres Freund, with changes by Amit Khandekar Discussion: https://postgr.es/m/20181105210039.hh4vvi4vwoq5ba2q@alap3.anarazel.de
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slot = MakeSingleTupleTableSlot(RelationGetDescr(heapRelation),
&TTSOpsHeapTuple);
ExecStoreHeapTuple(heapTuple, slot, false);
/*
* for each index, form and insert the index tuple
*/
for (i = 0; i < numIndexes; i++)
{
IndexInfo *indexInfo;
indexInfo = indexInfoArray[i];
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/* If the index is marked as read-only, ignore it */
if (!indexInfo->ii_ReadyForInserts)
continue;
/*
* Expressional and partial indexes on system catalogs are not
* supported, nor exclusion constraints, nor deferred uniqueness
*/
Assert(indexInfo->ii_Expressions == NIL);
Assert(indexInfo->ii_Predicate == NIL);
Assert(indexInfo->ii_ExclusionOps == NULL);
Assert(relationDescs[i]->rd_index->indimmediate);
Assert(indexInfo->ii_NumIndexKeyAttrs != 0);
/*
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* FormIndexDatum fills in its values and isnull parameters with the
* appropriate values for the column(s) of the index.
*/
FormIndexDatum(indexInfo,
slot,
NULL, /* no expression eval to do */
values,
isnull);
/*
* The index AM does the rest.
*/
index_insert(relationDescs[i], /* index relation */
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values, /* array of index Datums */
isnull, /* is-null flags */
Phase 2 of pgindent updates. Change pg_bsd_indent to follow upstream rules for placement of comments to the right of code, and remove pgindent hack that caused comments following #endif to not obey the general rule. Commit e3860ffa4dd0dad0dd9eea4be9cc1412373a8c89 wasn't actually using the published version of pg_bsd_indent, but a hacked-up version that tried to minimize the amount of movement of comments to the right of code. The situation of interest is where such a comment has to be moved to the right of its default placement at column 33 because there's code there. BSD indent has always moved right in units of tab stops in such cases --- but in the previous incarnation, indent was working in 8-space tab stops, while now it knows we use 4-space tabs. So the net result is that in about half the cases, such comments are placed one tab stop left of before. This is better all around: it leaves more room on the line for comment text, and it means that in such cases the comment uniformly starts at the next 4-space tab stop after the code, rather than sometimes one and sometimes two tabs after. Also, ensure that comments following #endif are indented the same as comments following other preprocessor commands such as #else. That inconsistency turns out to have been self-inflicted damage from a poorly-thought-through post-indent "fixup" in pgindent. This patch is much less interesting than the first round of indent changes, but also bulkier, so I thought it best to separate the effects. Discussion: https://postgr.es/m/E1dAmxK-0006EE-1r@gemulon.postgresql.org Discussion: https://postgr.es/m/30527.1495162840@sss.pgh.pa.us
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&(heapTuple->t_self), /* tid of heap tuple */
heapRelation,
relationDescs[i]->rd_index->indisunique ?
UNIQUE_CHECK_YES : UNIQUE_CHECK_NO,
indexInfo);
}
ExecDropSingleTupleTableSlot(slot);
}
/*
* CatalogTupleInsert - do heap and indexing work for a new catalog tuple
*
* Insert the tuple data in "tup" into the specified catalog relation.
* The Oid of the inserted tuple is returned.
*
* This is a convenience routine for the common case of inserting a single
* tuple in a system catalog; it inserts a new heap tuple, keeping indexes
* current. Avoid using it for multiple tuples, since opening the indexes
* and building the index info structures is moderately expensive.
* (Use CatalogTupleInsertWithInfo in such cases.)
*/
Oid
CatalogTupleInsert(Relation heapRel, HeapTuple tup)
{
CatalogIndexState indstate;
Oid oid;
indstate = CatalogOpenIndexes(heapRel);
oid = simple_heap_insert(heapRel, tup);
CatalogIndexInsert(indstate, tup);
CatalogCloseIndexes(indstate);
return oid;
}
/*
* CatalogTupleInsertWithInfo - as above, but with caller-supplied index info
*
* This should be used when it's important to amortize CatalogOpenIndexes/
* CatalogCloseIndexes work across multiple insertions. At some point we
* might cache the CatalogIndexState data somewhere (perhaps in the relcache)
* so that callers needn't trouble over this ... but we don't do so today.
*/
Oid
CatalogTupleInsertWithInfo(Relation heapRel, HeapTuple tup,
CatalogIndexState indstate)
{
Oid oid;
oid = simple_heap_insert(heapRel, tup);
CatalogIndexInsert(indstate, tup);
return oid;
}
/*
* CatalogTupleUpdate - do heap and indexing work for updating a catalog tuple
*
* Update the tuple identified by "otid", replacing it with the data in "tup".
*
* This is a convenience routine for the common case of updating a single
* tuple in a system catalog; it updates one heap tuple, keeping indexes
* current. Avoid using it for multiple tuples, since opening the indexes
* and building the index info structures is moderately expensive.
* (Use CatalogTupleUpdateWithInfo in such cases.)
*/
void
CatalogTupleUpdate(Relation heapRel, ItemPointer otid, HeapTuple tup)
{
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CatalogIndexState indstate;
indstate = CatalogOpenIndexes(heapRel);
simple_heap_update(heapRel, otid, tup);
CatalogIndexInsert(indstate, tup);
CatalogCloseIndexes(indstate);
}
/*
* CatalogTupleUpdateWithInfo - as above, but with caller-supplied index info
*
* This should be used when it's important to amortize CatalogOpenIndexes/
* CatalogCloseIndexes work across multiple updates. At some point we
* might cache the CatalogIndexState data somewhere (perhaps in the relcache)
* so that callers needn't trouble over this ... but we don't do so today.
*/
void
CatalogTupleUpdateWithInfo(Relation heapRel, ItemPointer otid, HeapTuple tup,
CatalogIndexState indstate)
{
simple_heap_update(heapRel, otid, tup);
CatalogIndexInsert(indstate, tup);
}
/*
* CatalogTupleDelete - do heap and indexing work for deleting a catalog tuple
*
* Delete the tuple identified by "tid" in the specified catalog.
*
* With Postgres heaps, there is no index work to do at deletion time;
* cleanup will be done later by VACUUM. However, callers of this function
* shouldn't have to know that; we'd like a uniform abstraction for all
* catalog tuple changes. Hence, provide this currently-trivial wrapper.
*
* The abstraction is a bit leaky in that we don't provide an optimized
* CatalogTupleDeleteWithInfo version, because there is currently nothing to
* optimize. If we ever need that, rather than touching a lot of call sites,
* it might be better to do something about caching CatalogIndexState.
*/
void
CatalogTupleDelete(Relation heapRel, ItemPointer tid)
{
simple_heap_delete(heapRel, tid);
}