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postgresql/src/backend/commands/vacuum.c

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/*-------------------------------------------------------------------------
*
* vacuum.c
* the postgres vacuum cleaner
*
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California
*
*
* IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.163 2000/07/14 22:17:42 tgl Exp $
*
*-------------------------------------------------------------------------
*/
#include <sys/types.h>
#include <sys/file.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include "postgres.h"
#include "access/genam.h"
#include "access/heapam.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/index.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
#include "nodes/execnodes.h"
#include "storage/sinval.h"
#include "storage/smgr.h"
#include "tcop/tcopprot.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/fmgroids.h"
#include "utils/inval.h"
#include "utils/relcache.h"
#include "utils/syscache.h"
#include "utils/temprel.h"
#ifndef HAVE_GETRUSAGE
#include "rusagestub.h"
#else
#include <sys/time.h>
#include <sys/resource.h>
#endif
static MemoryContext vac_context = NULL;
static int MESSAGE_LEVEL; /* message level */
static TransactionId XmaxRecent;
/* non-export function prototypes */
static void vacuum_init(void);
static void vacuum_shutdown(void);
static void vac_vacuum(NameData *VacRelP, bool analyze, List *anal_cols2);
static VRelList getrels(NameData *VacRelP);
static void vacuum_rel(Oid relid, bool analyze, bool is_toastrel);
static void scan_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages, VacPageList fraged_pages);
static void repair_frag(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages, VacPageList fraged_pages, int nindices, Relation *Irel);
static void vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacpagelist);
static void vacuum_page(Page page, VacPage vacpage);
static void vacuum_index(VacPageList vacpagelist, Relation indrel, int num_tuples, int keep_tuples);
static void scan_index(Relation indrel, int num_tuples);
static void update_relstats(Oid relid, int num_pages, int num_tuples, bool hasindex, VRelStats *vacrelstats);
static VacPage tid_reaped(ItemPointer itemptr, VacPageList vacpagelist);
static void reap_page(VacPageList vacpagelist, VacPage vacpage);
static void vpage_insert(VacPageList vacpagelist, VacPage vpnew);
static void get_indices(Relation relation, int *nindices, Relation **Irel);
static void close_indices(int nindices, Relation *Irel);
static IndexInfo **get_index_desc(Relation onerel, int nindices,
Relation *Irel);
static void *vac_find_eq(void *bot, int nelem, int size, void *elm,
int (*compar) (const void *, const void *));
static int vac_cmp_blk(const void *left, const void *right);
static int vac_cmp_offno(const void *left, const void *right);
static int vac_cmp_vtlinks(const void *left, const void *right);
static bool enough_space(VacPage vacpage, Size len);
static char *show_rusage(struct rusage * ru0);
void
vacuum(char *vacrel, bool verbose, bool analyze, List *anal_cols)
{
NameData VacRel;
Name VacRelName;
MemoryContext old;
List *le;
List *anal_cols2 = NIL;
if (anal_cols != NIL && !analyze)
elog(ERROR, "Can't vacuum columns, only tables. You can 'vacuum analyze' columns.");
/*
* We cannot run VACUUM inside a user transaction block; if we were
* inside a transaction, then our commit- and
* start-transaction-command calls would not have the intended effect!
* Furthermore, the forced commit that occurs before truncating the
* relation's file would have the effect of committing the rest of the
* user's transaction too, which would certainly not be the desired
* behavior.
*/
if (IsTransactionBlock())
elog(ERROR, "VACUUM cannot run inside a BEGIN/END block");
if (verbose)
MESSAGE_LEVEL = NOTICE;
else
MESSAGE_LEVEL = DEBUG;
/*
* Create special memory context for cross-transaction storage.
*
* Since it is a child of QueryContext, it will go away eventually
* even if we suffer an error; there's no need for special abort
* cleanup logic.
*/
vac_context = AllocSetContextCreate(QueryContext,
"Vacuum",
ALLOCSET_DEFAULT_MINSIZE,
ALLOCSET_DEFAULT_INITSIZE,
ALLOCSET_DEFAULT_MAXSIZE);
/* vacrel gets de-allocated on xact commit, so copy it to safe storage */
if (vacrel)
{
namestrcpy(&VacRel, vacrel);
VacRelName = &VacRel;
}
else
VacRelName = NULL;
/* must also copy the column list, if any, to safe storage */
old = MemoryContextSwitchTo(vac_context);
foreach(le, anal_cols)
{
char *col = (char *) lfirst(le);
anal_cols2 = lappend(anal_cols2, pstrdup(col));
}
MemoryContextSwitchTo(old);
/*
* Start up the vacuum cleaner.
*
* NOTE: since this commits the current transaction, the memory holding
* any passed-in parameters gets freed here. We must have already
* copied pass-by-reference parameters to safe storage. Don't make me
* fix this again!
*/
vacuum_init();
/* vacuum the database */
vac_vacuum(VacRelName, analyze, anal_cols2);
/* clean up */
vacuum_shutdown();
}
/*
* vacuum_init(), vacuum_shutdown() -- start up and shut down the vacuum cleaner.
*
* Formerly, there was code here to prevent more than one VACUUM from
* executing concurrently in the same database. However, there's no
* good reason to prevent that, and manually removing lockfiles after
* a vacuum crash was a pain for dbadmins. So, forget about lockfiles,
* and just rely on the exclusive lock we grab on each target table
* to ensure that there aren't two VACUUMs running on the same table
* at the same time.
*
* The strangeness with committing and starting transactions in the
* init and shutdown routines is due to the fact that the vacuum cleaner
* is invoked via an SQL command, and so is already executing inside
* a transaction. We need to leave ourselves in a predictable state
* on entry and exit to the vacuum cleaner. We commit the transaction
* started in PostgresMain() inside vacuum_init(), and start one in
* vacuum_shutdown() to match the commit waiting for us back in
* PostgresMain().
*/
static void
vacuum_init()
{
/* matches the StartTransaction in PostgresMain() */
CommitTransactionCommand();
}
static void
vacuum_shutdown()
{
/* on entry, we are not in a transaction */
/*
* Flush the init file that relcache.c uses to save startup time. The
* next backend startup will rebuild the init file with up-to-date
* information from pg_class. This lets the optimizer see the stats
* that we've collected for certain critical system indexes. See
* relcache.c for more details.
*
* Ignore any failure to unlink the file, since it might not be there if
* no backend has been started since the last vacuum...
*/
unlink(RELCACHE_INIT_FILENAME);
/* matches the CommitTransaction in PostgresMain() */
StartTransactionCommand();
/*
* Clean up working storage --- note we must do this after
* StartTransactionCommand, else we might be trying to delete
* the active context!
*/
MemoryContextDelete(vac_context);
vac_context = NULL;
}
/*
* vac_vacuum() -- vacuum the database.
*
* This routine builds a list of relations to vacuum, and then calls
* code that vacuums them one at a time. We are careful to vacuum each
* relation in a separate transaction in order to avoid holding too many
* locks at one time.
*/
static void
vac_vacuum(NameData *VacRelP, bool analyze, List *anal_cols2)
{
VRelList vrl,
cur;
/* get list of relations */
vrl = getrels(VacRelP);
/* vacuum each heap relation */
for (cur = vrl; cur != (VRelList) NULL; cur = cur->vrl_next)
{
vacuum_rel(cur->vrl_relid, analyze, false);
/* analyze separately so locking is minimized */
if (analyze)
analyze_rel(cur->vrl_relid, anal_cols2, MESSAGE_LEVEL);
}
}
static VRelList
getrels(NameData *VacRelP)
{
Relation rel;
TupleDesc tupdesc;
HeapScanDesc scan;
HeapTuple tuple;
VRelList vrl,
cur;
Datum d;
char *rname;
char rkind;
bool n;
bool found = false;
ScanKeyData key;
StartTransactionCommand();
if (NameStr(*VacRelP))
{
/*
* we could use the cache here, but it is clearer to use scankeys
* for both vacuum cases, bjm 2000/01/19
*/
char *nontemp_relname;
/* We must re-map temp table names bjm 2000-04-06 */
if ((nontemp_relname =
get_temp_rel_by_username(NameStr(*VacRelP))) == NULL)
nontemp_relname = NameStr(*VacRelP);
ScanKeyEntryInitialize(&key, 0x0, Anum_pg_class_relname,
F_NAMEEQ,
PointerGetDatum(nontemp_relname));
}
else
{
ScanKeyEntryInitialize(&key, 0x0, Anum_pg_class_relkind,
F_CHAREQ, CharGetDatum('r'));
}
vrl = cur = (VRelList) NULL;
rel = heap_openr(RelationRelationName, AccessShareLock);
tupdesc = RelationGetDescr(rel);
scan = heap_beginscan(rel, false, SnapshotNow, 1, &key);
while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
{
found = true;
d = heap_getattr(tuple, Anum_pg_class_relname, tupdesc, &n);
rname = (char *) d;
d = heap_getattr(tuple, Anum_pg_class_relkind, tupdesc, &n);
rkind = DatumGetChar(d);
if (rkind != RELKIND_RELATION)
{
elog(NOTICE, "Vacuum: can not process index and certain system tables");
continue;
}
/* get a relation list entry for this guy */
if (vrl == (VRelList) NULL)
vrl = cur = (VRelList)
MemoryContextAlloc(vac_context, sizeof(VRelListData));
else
{
cur->vrl_next = (VRelList)
MemoryContextAlloc(vac_context, sizeof(VRelListData));
cur = cur->vrl_next;
}
cur->vrl_relid = tuple->t_data->t_oid;
cur->vrl_next = (VRelList) NULL;
}
heap_endscan(scan);
heap_close(rel, AccessShareLock);
if (!found)
elog(NOTICE, "Vacuum: table not found");
CommitTransactionCommand();
return vrl;
}
/*
* vacuum_rel() -- vacuum one heap relation
*
* This routine vacuums a single heap, cleans out its indices, and
* updates its statistics num_pages and num_tuples statistics.
*
* Doing one heap at a time incurs extra overhead, since we need to
* check that the heap exists again just before we vacuum it. The
* reason that we do this is so that vacuuming can be spread across
* many small transactions. Otherwise, two-phase locking would require
* us to lock the entire database during one pass of the vacuum cleaner.
*/
static void
vacuum_rel(Oid relid, bool analyze, bool is_toastrel)
{
HeapTuple tuple;
Relation onerel;
VacPageListData vacuum_pages; /* List of pages to vacuum and/or clean
* indices */
VacPageListData fraged_pages; /* List of pages with space enough for
* re-using */
VacPage *vacpage;
Relation *Irel;
int32 nindices,
i;
VRelStats *vacrelstats;
bool reindex = false;
Oid toast_relid;
if (!is_toastrel)
StartTransactionCommand();
/*
* Check for user-requested abort. Note we want this to be inside a
* transaction, so xact.c doesn't issue useless NOTICE.
*/
if (QueryCancel)
CancelQuery();
/*
* Race condition -- if the pg_class tuple has gone away since the
* last time we saw it, we don't need to vacuum it.
*/
tuple = SearchSysCacheTuple(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(tuple))
{
if (!is_toastrel)
CommitTransactionCommand();
return;
}
/*
* Open the class, get an exclusive lock on it, and check permissions.
*
* Note we choose to treat permissions failure as a NOTICE and keep
* trying to vacuum the rest of the DB --- is this appropriate?
*/
onerel = heap_open(relid, AccessExclusiveLock);
/*
* Remember the relations TOAST relation for later
*
*/
toast_relid = onerel->rd_rel->reltoastrelid;
#ifndef NO_SECURITY
if (!pg_ownercheck(GetPgUserName(), RelationGetRelationName(onerel),
RELNAME))
{
elog(NOTICE, "Skipping \"%s\" --- only table owner can VACUUM it",
RelationGetRelationName(onerel));
heap_close(onerel, AccessExclusiveLock);
if (!is_toastrel)
CommitTransactionCommand();
return;
}
#endif
/*
* Set up statistics-gathering machinery.
*/
vacrelstats = (VRelStats *) palloc(sizeof(VRelStats));
vacrelstats->relid = relid;
vacrelstats->num_pages = vacrelstats->num_tuples = 0;
vacrelstats->hasindex = false;
GetXmaxRecent(&XmaxRecent);
/* scan it */
reindex = false;
vacuum_pages.num_pages = fraged_pages.num_pages = 0;
scan_heap(vacrelstats, onerel, &vacuum_pages, &fraged_pages);
if (IsIgnoringSystemIndexes() && IsSystemRelationName(RelationGetRelationName(onerel)))
reindex = true;
/* Now open indices */
nindices = 0;
Irel = (Relation *) NULL;
get_indices(onerel, &nindices, &Irel);
if (!Irel)
reindex = false;
else if (!RelationGetForm(onerel)->relhasindex)
reindex = true;
if (nindices > 0)
vacrelstats->hasindex = true;
else
vacrelstats->hasindex = false;
if (reindex)
{
for (i = 0; i < nindices; i++)
index_close(Irel[i]);
Irel = (Relation *) NULL;
activate_indexes_of_a_table(relid, false);
}
/* Clean/scan index relation(s) */
if (Irel != (Relation *) NULL)
{
if (vacuum_pages.num_pages > 0)
{
for (i = 0; i < nindices; i++)
vacuum_index(&vacuum_pages, Irel[i], vacrelstats->num_tuples, 0);
}
else
/* just scan indices to update statistic */
{
for (i = 0; i < nindices; i++)
scan_index(Irel[i], vacrelstats->num_tuples);
}
}
if (fraged_pages.num_pages > 0) /* Try to shrink heap */
repair_frag(vacrelstats, onerel, &vacuum_pages, &fraged_pages, nindices, Irel);
else
{
if (Irel != (Relation *) NULL)
close_indices(nindices, Irel);
if (vacuum_pages.num_pages > 0) /* Clean pages from
* vacuum_pages list */
vacuum_heap(vacrelstats, onerel, &vacuum_pages);
}
if (reindex)
activate_indexes_of_a_table(relid, true);
/* ok - free vacuum_pages list of reaped pages */
if (vacuum_pages.num_pages > 0)
{
vacpage = vacuum_pages.pagedesc;
for (i = 0; i < vacuum_pages.num_pages; i++, vacpage++)
pfree(*vacpage);
pfree(vacuum_pages.pagedesc);
if (fraged_pages.num_pages > 0)
pfree(fraged_pages.pagedesc);
}
/* all done with this class, but hold lock until commit */
heap_close(onerel, NoLock);
/* update statistics in pg_class */
update_relstats(vacrelstats->relid, vacrelstats->num_pages,
vacrelstats->num_tuples, vacrelstats->hasindex, vacrelstats);
/* If the relation has a secondary toast one, vacuum that too
* while we still hold the lock on the master table. We don't
* need to propagate "analyze" to it, because the toaster
* allways uses hardcoded index access and statistics are
* totally unimportant for toast relations
*/
if (toast_relid != InvalidOid)
vacuum_rel(toast_relid, false, true);
/* next command frees attribute stats */
if (!is_toastrel)
CommitTransactionCommand();
}
/*
* scan_heap() -- scan an open heap relation
*
* This routine sets commit times, constructs vacuum_pages list of
* empty/uninitialized pages and pages with dead tuples and
* ~LP_USED line pointers, constructs fraged_pages list of pages
* appropriate for purposes of shrinking and maintains statistics
* on the number of live tuples in a heap.
*/
static void
scan_heap(VRelStats *vacrelstats, Relation onerel,
VacPageList vacuum_pages, VacPageList fraged_pages)
{
BlockNumber nblocks,
blkno;
ItemId itemid;
Buffer buf;
HeapTupleData tuple;
Page page,
tempPage = NULL;
OffsetNumber offnum,
maxoff;
bool pgchanged,
tupgone,
dobufrel,
notup;
char *relname;
VacPage vacpage,
vp;
uint32 tups_vacuumed,
num_tuples,
nkeep,
nunused,
ncrash,
empty_pages,
new_pages,
changed_pages,
empty_end_pages;
Size free_size,
usable_free_size;
Size min_tlen = MaxTupleSize;
Size max_tlen = 0;
int32 i;
bool do_shrinking = true;
VTupleLink vtlinks = (VTupleLink) palloc(100 * sizeof(VTupleLinkData));
int num_vtlinks = 0;
int free_vtlinks = 100;
struct rusage ru0;
getrusage(RUSAGE_SELF, &ru0);
relname = RelationGetRelationName(onerel);
elog(MESSAGE_LEVEL, "--Relation %s--", relname);
tups_vacuumed = num_tuples = nkeep = nunused = ncrash = empty_pages =
new_pages = changed_pages = empty_end_pages = 0;
free_size = usable_free_size = 0;
nblocks = RelationGetNumberOfBlocks(onerel);
vacpage = (VacPage) palloc(sizeof(VacPageData) + MaxOffsetNumber * sizeof(OffsetNumber));
vacpage->offsets_used = 0;
for (blkno = 0; blkno < nblocks; blkno++)
{
buf = ReadBuffer(onerel, blkno);
page = BufferGetPage(buf);
vacpage->blkno = blkno;
vacpage->offsets_free = 0;
if (PageIsNew(page))
{
elog(NOTICE, "Rel %s: Uninitialized page %u - fixing",
relname, blkno);
PageInit(page, BufferGetPageSize(buf), 0);
vacpage->free = ((PageHeader) page)->pd_upper - ((PageHeader) page)->pd_lower;
free_size += (vacpage->free - sizeof(ItemIdData));
new_pages++;
empty_end_pages++;
reap_page(vacuum_pages, vacpage);
WriteBuffer(buf);
continue;
}
if (PageIsEmpty(page))
{
vacpage->free = ((PageHeader) page)->pd_upper - ((PageHeader) page)->pd_lower;
free_size += (vacpage->free - sizeof(ItemIdData));
empty_pages++;
empty_end_pages++;
reap_page(vacuum_pages, vacpage);
ReleaseBuffer(buf);
continue;
}
pgchanged = false;
notup = true;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
itemid = PageGetItemId(page, offnum);
/*
* Collect un-used items too - it's possible to have indices
* pointing here after crash.
*/
if (!ItemIdIsUsed(itemid))
{
vacpage->offsets[vacpage->offsets_free++] = offnum;
nunused++;
continue;
}
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
tuple.t_len = ItemIdGetLength(itemid);
ItemPointerSet(&(tuple.t_self), blkno, offnum);
tupgone = false;
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
if (tuple.t_data->t_infomask & HEAP_XMIN_INVALID)
tupgone = true;
else if (tuple.t_data->t_infomask & HEAP_MOVED_OFF)
{
if (TransactionIdDidCommit((TransactionId)
tuple.t_data->t_cmin))
{
tuple.t_data->t_infomask |= HEAP_XMIN_INVALID;
tupgone = true;
}
else
{
tuple.t_data->t_infomask |= HEAP_XMIN_COMMITTED;
pgchanged = true;
}
}
else if (tuple.t_data->t_infomask & HEAP_MOVED_IN)
{
if (!TransactionIdDidCommit((TransactionId)
tuple.t_data->t_cmin))
{
tuple.t_data->t_infomask |= HEAP_XMIN_INVALID;
tupgone = true;
}
else
{
tuple.t_data->t_infomask |= HEAP_XMIN_COMMITTED;
pgchanged = true;
}
}
else
{
if (TransactionIdDidAbort(tuple.t_data->t_xmin))
tupgone = true;
else if (TransactionIdDidCommit(tuple.t_data->t_xmin))
{
tuple.t_data->t_infomask |= HEAP_XMIN_COMMITTED;
pgchanged = true;
}
else if (!TransactionIdIsInProgress(tuple.t_data->t_xmin))
{
/*
* Not Aborted, Not Committed, Not in Progress -
* so it's from crashed process. - vadim 11/26/96
*/
ncrash++;
tupgone = true;
}
else
{
elog(NOTICE, "Rel %s: TID %u/%u: InsertTransactionInProgress %u - can't shrink relation",
relname, blkno, offnum, tuple.t_data->t_xmin);
do_shrinking = false;
}
}
}
/*
* here we are concerned about tuples with xmin committed and
* xmax unknown or committed
*/
if (tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED &&
!(tuple.t_data->t_infomask & HEAP_XMAX_INVALID))
{
if (tuple.t_data->t_infomask & HEAP_XMAX_COMMITTED)
{
if (tuple.t_data->t_infomask & HEAP_MARKED_FOR_UPDATE)
{
pgchanged = true;
tuple.t_data->t_infomask |= HEAP_XMAX_INVALID;
}
else
tupgone = true;
}
else if (TransactionIdDidAbort(tuple.t_data->t_xmax))
{
tuple.t_data->t_infomask |= HEAP_XMAX_INVALID;
pgchanged = true;
}
else if (TransactionIdDidCommit(tuple.t_data->t_xmax))
{
if (tuple.t_data->t_infomask & HEAP_MARKED_FOR_UPDATE)
{
tuple.t_data->t_infomask |= HEAP_XMAX_INVALID;
pgchanged = true;
}
else
tupgone = true;
}
else if (!TransactionIdIsInProgress(tuple.t_data->t_xmax))
{
/*
* Not Aborted, Not Committed, Not in Progress - so it
* from crashed process. - vadim 06/02/97
*/
tuple.t_data->t_infomask |= HEAP_XMAX_INVALID;
pgchanged = true;
}
else
{
elog(NOTICE, "Rel %s: TID %u/%u: DeleteTransactionInProgress %u - can't shrink relation",
relname, blkno, offnum, tuple.t_data->t_xmax);
do_shrinking = false;
}
/*
* If tuple is recently deleted then we must not remove it
* from relation.
*/
if (tupgone && (tuple.t_data->t_infomask & HEAP_XMIN_INVALID) == 0 && tuple.t_data->t_xmax >= XmaxRecent)
{
tupgone = false;
nkeep++;
if (!(tuple.t_data->t_infomask & HEAP_XMAX_COMMITTED))
{
tuple.t_data->t_infomask |= HEAP_XMAX_COMMITTED;
pgchanged = true;
}
/*
* If we do shrinking and this tuple is updated one
* then remember it to construct updated tuple
* dependencies.
*/
if (do_shrinking && !(ItemPointerEquals(&(tuple.t_self),
&(tuple.t_data->t_ctid))))
{
if (free_vtlinks == 0)
{
free_vtlinks = 1000;
vtlinks = (VTupleLink) repalloc(vtlinks,
(free_vtlinks + num_vtlinks) *
sizeof(VTupleLinkData));
}
vtlinks[num_vtlinks].new_tid = tuple.t_data->t_ctid;
vtlinks[num_vtlinks].this_tid = tuple.t_self;
free_vtlinks--;
num_vtlinks++;
}
}
}
/*
* Other checks...
*/
if (!OidIsValid(tuple.t_data->t_oid))
{
elog(NOTICE, "Rel %s: TID %u/%u: OID IS INVALID. TUPGONE %d.",
relname, blkno, offnum, tupgone);
}
if (tupgone)
{
ItemId lpp;
if (tempPage == (Page) NULL)
{
Size pageSize;
pageSize = PageGetPageSize(page);
tempPage = (Page) palloc(pageSize);
memmove(tempPage, page, pageSize);
}
lpp = &(((PageHeader) tempPage)->pd_linp[offnum - 1]);
/* mark it unused */
lpp->lp_flags &= ~LP_USED;
vacpage->offsets[vacpage->offsets_free++] = offnum;
tups_vacuumed++;
}
else
{
num_tuples++;
notup = false;
if (tuple.t_len < min_tlen)
min_tlen = tuple.t_len;
if (tuple.t_len > max_tlen)
max_tlen = tuple.t_len;
}
}
if (pgchanged)
{
WriteBuffer(buf);
dobufrel = false;
changed_pages++;
}
else
dobufrel = true;
if (tempPage != (Page) NULL)
{ /* Some tuples are gone */
PageRepairFragmentation(tempPage);
vacpage->free = ((PageHeader) tempPage)->pd_upper - ((PageHeader) tempPage)->pd_lower;
free_size += vacpage->free;
reap_page(vacuum_pages, vacpage);
pfree(tempPage);
tempPage = (Page) NULL;
}
else if (vacpage->offsets_free > 0)
{ /* there are only ~LP_USED line pointers */
vacpage->free = ((PageHeader) page)->pd_upper - ((PageHeader) page)->pd_lower;
free_size += vacpage->free;
reap_page(vacuum_pages, vacpage);
}
if (dobufrel)
ReleaseBuffer(buf);
if (notup)
empty_end_pages++;
else
empty_end_pages = 0;
}
pfree(vacpage);
/* save stats in the rel list for use later */
vacrelstats->num_tuples = num_tuples;
vacrelstats->num_pages = nblocks;
/* vacrelstats->natts = attr_cnt;*/
if (num_tuples == 0)
min_tlen = max_tlen = 0;
vacrelstats->min_tlen = min_tlen;
vacrelstats->max_tlen = max_tlen;
vacuum_pages->empty_end_pages = empty_end_pages;
fraged_pages->empty_end_pages = empty_end_pages;
/*
* Try to make fraged_pages keeping in mind that we can't use free
* space of "empty" end-pages and last page if it reaped.
*/
if (do_shrinking && vacuum_pages->num_pages - empty_end_pages > 0)
{
int nusf; /* blocks usefull for re-using */
nusf = vacuum_pages->num_pages - empty_end_pages;
if ((vacuum_pages->pagedesc[nusf - 1])->blkno == nblocks - empty_end_pages - 1)
nusf--;
for (i = 0; i < nusf; i++)
{
vp = vacuum_pages->pagedesc[i];
if (enough_space(vp, min_tlen))
{
vpage_insert(fraged_pages, vp);
usable_free_size += vp->free;
}
}
}
if (usable_free_size > 0 && num_vtlinks > 0)
{
qsort((char *) vtlinks, num_vtlinks, sizeof(VTupleLinkData),
vac_cmp_vtlinks);
vacrelstats->vtlinks = vtlinks;
vacrelstats->num_vtlinks = num_vtlinks;
}
else
{
vacrelstats->vtlinks = NULL;
vacrelstats->num_vtlinks = 0;
pfree(vtlinks);
}
elog(MESSAGE_LEVEL, "Pages %u: Changed %u, reaped %u, Empty %u, New %u; \
Tup %u: Vac %u, Keep/VTL %u/%u, Crash %u, UnUsed %u, MinLen %u, MaxLen %u; \
Re-using: Free/Avail. Space %u/%u; EndEmpty/Avail. Pages %u/%u. %s",
nblocks, changed_pages, vacuum_pages->num_pages, empty_pages,
new_pages, num_tuples, tups_vacuumed,
nkeep, vacrelstats->num_vtlinks, ncrash,
nunused, min_tlen, max_tlen, free_size, usable_free_size,
empty_end_pages, fraged_pages->num_pages,
show_rusage(&ru0));
}
/*
* repair_frag() -- try to repair relation's fragmentation
*
* This routine marks dead tuples as unused and tries re-use dead space
* by moving tuples (and inserting indices if needed). It constructs
* Nvacpagelist list of free-ed pages (moved tuples) and clean indices
* for them after committing (in hack-manner - without losing locks
* and freeing memory!) current transaction. It truncates relation
* if some end-blocks are gone away.
*/
static void
repair_frag(VRelStats *vacrelstats, Relation onerel,
VacPageList vacuum_pages, VacPageList fraged_pages,
int nindices, Relation *Irel)
{
TransactionId myXID;
CommandId myCID;
Buffer buf,
cur_buffer;
int nblocks,
blkno;
Page page,
ToPage = NULL;
OffsetNumber offnum = 0,
maxoff = 0,
newoff,
max_offset;
ItemId itemid,
newitemid;
HeapTupleData tuple,
newtup;
TupleDesc tupdesc;
IndexInfo **indexInfo = NULL;
Datum idatum[INDEX_MAX_KEYS];
char inulls[INDEX_MAX_KEYS];
InsertIndexResult iresult;
VacPageListData Nvacpagelist;
VacPage cur_page = NULL,
last_vacuum_page,
vacpage,
*curpage;
int cur_item = 0;
int last_move_dest_block = -1,
last_vacuum_block,
i = 0;
Size tuple_len;
int num_moved,
num_fraged_pages,
vacuumed_pages;
int checked_moved,
num_tuples,
keep_tuples = 0;
bool isempty,
dowrite,
chain_tuple_moved;
struct rusage ru0;
getrusage(RUSAGE_SELF, &ru0);
myXID = GetCurrentTransactionId();
myCID = GetCurrentCommandId();
tupdesc = RelationGetDescr(onerel);
if (Irel != (Relation *) NULL) /* preparation for index' inserts */
indexInfo = get_index_desc(onerel, nindices, Irel);
Nvacpagelist.num_pages = 0;
num_fraged_pages = fraged_pages->num_pages;
Assert(vacuum_pages->num_pages > vacuum_pages->empty_end_pages);
vacuumed_pages = vacuum_pages->num_pages - vacuum_pages->empty_end_pages;
last_vacuum_page = vacuum_pages->pagedesc[vacuumed_pages - 1];
last_vacuum_block = last_vacuum_page->blkno;
cur_buffer = InvalidBuffer;
num_moved = 0;
vacpage = (VacPage) palloc(sizeof(VacPageData) + MaxOffsetNumber * sizeof(OffsetNumber));
vacpage->offsets_used = vacpage->offsets_free = 0;
/*
* Scan pages backwards from the last nonempty page, trying to move
* tuples down to lower pages. Quit when we reach a page that we have
* moved any tuples onto. Note that if a page is still in the
* fraged_pages list (list of candidate move-target pages) when we
* reach it, we will remove it from the list. This ensures we never
* move a tuple up to a higher page number.
*
* NB: this code depends on the vacuum_pages and fraged_pages lists being
* in order, and on fraged_pages being a subset of vacuum_pages.
*/
nblocks = vacrelstats->num_pages;
for (blkno = nblocks - vacuum_pages->empty_end_pages - 1;
blkno > last_move_dest_block;
blkno--)
{
buf = ReadBuffer(onerel, blkno);
page = BufferGetPage(buf);
vacpage->offsets_free = 0;
isempty = PageIsEmpty(page);
dowrite = false;
if (blkno == last_vacuum_block) /* it's reaped page */
{
if (last_vacuum_page->offsets_free > 0) /* there are dead tuples */
{ /* on this page - clean */
Assert(!isempty);
vacuum_page(page, last_vacuum_page);
dowrite = true;
}
else
Assert(isempty);
--vacuumed_pages;
if (vacuumed_pages > 0)
{
/* get prev reaped page from vacuum_pages */
last_vacuum_page = vacuum_pages->pagedesc[vacuumed_pages - 1];
last_vacuum_block = last_vacuum_page->blkno;
}
else
{
last_vacuum_page = NULL;
last_vacuum_block = -1;
}
if (num_fraged_pages > 0 &&
fraged_pages->pagedesc[num_fraged_pages - 1]->blkno ==
(BlockNumber) blkno)
{
/* page is in fraged_pages too; remove it */
--num_fraged_pages;
}
if (isempty)
{
ReleaseBuffer(buf);
continue;
}
}
else
Assert(!isempty);
chain_tuple_moved = false; /* no one chain-tuple was moved
* off this page, yet */
vacpage->blkno = blkno;
maxoff = PageGetMaxOffsetNumber(page);
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
itemid = PageGetItemId(page, offnum);
if (!ItemIdIsUsed(itemid))
continue;
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
tuple_len = tuple.t_len = ItemIdGetLength(itemid);
ItemPointerSet(&(tuple.t_self), blkno, offnum);
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
if ((TransactionId) tuple.t_data->t_cmin != myXID)
elog(ERROR, "Invalid XID in t_cmin");
if (tuple.t_data->t_infomask & HEAP_MOVED_IN)
elog(ERROR, "HEAP_MOVED_IN was not expected");
/*
* If this (chain) tuple is moved by me already then I
* have to check is it in vacpage or not - i.e. is it moved
* while cleaning this page or some previous one.
*/
if (tuple.t_data->t_infomask & HEAP_MOVED_OFF)
{
if (keep_tuples == 0)
continue;
if (chain_tuple_moved) /* some chains was moved
* while */
{ /* cleaning this page */
Assert(vacpage->offsets_free > 0);
for (i = 0; i < vacpage->offsets_free; i++)
{
if (vacpage->offsets[i] == offnum)
break;
}
if (i >= vacpage->offsets_free) /* not found */
{
vacpage->offsets[vacpage->offsets_free++] = offnum;
keep_tuples--;
}
}
else
{
vacpage->offsets[vacpage->offsets_free++] = offnum;
keep_tuples--;
}
continue;
}
elog(ERROR, "HEAP_MOVED_OFF was expected");
}
/*
* If this tuple is in the chain of tuples created in updates
* by "recent" transactions then we have to move all chain of
* tuples to another places.
*/
if ((tuple.t_data->t_infomask & HEAP_UPDATED &&
tuple.t_data->t_xmin >= XmaxRecent) ||
(!(tuple.t_data->t_infomask & HEAP_XMAX_INVALID) &&
!(ItemPointerEquals(&(tuple.t_self), &(tuple.t_data->t_ctid)))))
{
Buffer Cbuf = buf;
Page Cpage;
ItemId Citemid;
ItemPointerData Ctid;
HeapTupleData tp = tuple;
Size tlen = tuple_len;
VTupleMove vtmove = (VTupleMove)
palloc(100 * sizeof(VTupleMoveData));
int num_vtmove = 0;
int free_vtmove = 100;
VacPage to_vacpage = NULL;
int to_item = 0;
bool freeCbuf = false;
int ti;
if (vacrelstats->vtlinks == NULL)
elog(ERROR, "No one parent tuple was found");
if (cur_buffer != InvalidBuffer)
{
WriteBuffer(cur_buffer);
cur_buffer = InvalidBuffer;
}
/*
* If this tuple is in the begin/middle of the chain then
* we have to move to the end of chain.
*/
while (!(tp.t_data->t_infomask & HEAP_XMAX_INVALID) &&
!(ItemPointerEquals(&(tp.t_self), &(tp.t_data->t_ctid))))
{
Ctid = tp.t_data->t_ctid;
if (freeCbuf)
ReleaseBuffer(Cbuf);
freeCbuf = true;
Cbuf = ReadBuffer(onerel,
ItemPointerGetBlockNumber(&Ctid));
Cpage = BufferGetPage(Cbuf);
Citemid = PageGetItemId(Cpage,
ItemPointerGetOffsetNumber(&Ctid));
if (!ItemIdIsUsed(Citemid))
{
/*
* This means that in the middle of chain there
* was tuple updated by older (than XmaxRecent)
* xaction and this tuple is already deleted by
* me. Actually, upper part of chain should be
* removed and seems that this should be handled
* in scan_heap(), but it's not implemented at
* the moment and so we just stop shrinking here.
*/
ReleaseBuffer(Cbuf);
pfree(vtmove);
vtmove = NULL;
elog(NOTICE, "Child itemid in update-chain marked as unused - can't continue repair_frag");
break;
}
tp.t_datamcxt = NULL;
tp.t_data = (HeapTupleHeader) PageGetItem(Cpage, Citemid);
tp.t_self = Ctid;
tlen = tp.t_len = ItemIdGetLength(Citemid);
}
if (vtmove == NULL)
break;
/* first, can chain be moved ? */
for (;;)
{
if (to_vacpage == NULL ||
!enough_space(to_vacpage, tlen))
{
/*
* if to_vacpage no longer has enough free space to be
* useful, remove it from fraged_pages list
*/
if (to_vacpage != NULL &&
!enough_space(to_vacpage, vacrelstats->min_tlen))
{
Assert(num_fraged_pages > to_item);
memmove(fraged_pages->pagedesc + to_item,
fraged_pages->pagedesc + to_item + 1,
sizeof(VacPage) * (num_fraged_pages - to_item - 1));
num_fraged_pages--;
}
for (i = 0; i < num_fraged_pages; i++)
{
if (enough_space(fraged_pages->pagedesc[i], tlen))
break;
}
/* can't move item anywhere */
if (i == num_fraged_pages)
{
for (i = 0; i < num_vtmove; i++)
{
Assert(vtmove[i].vacpage->offsets_used > 0);
(vtmove[i].vacpage->offsets_used)--;
}
num_vtmove = 0;
break;
}
to_item = i;
to_vacpage = fraged_pages->pagedesc[to_item];
}
to_vacpage->free -= MAXALIGN(tlen);
if (to_vacpage->offsets_used >= to_vacpage->offsets_free)
to_vacpage->free -= MAXALIGN(sizeof(ItemIdData));
(to_vacpage->offsets_used)++;
if (free_vtmove == 0)
{
free_vtmove = 1000;
vtmove = (VTupleMove) repalloc(vtmove,
(free_vtmove + num_vtmove) *
sizeof(VTupleMoveData));
}
vtmove[num_vtmove].tid = tp.t_self;
vtmove[num_vtmove].vacpage = to_vacpage;
if (to_vacpage->offsets_used == 1)
vtmove[num_vtmove].cleanVpd = true;
else
vtmove[num_vtmove].cleanVpd = false;
free_vtmove--;
num_vtmove++;
/* All done ? */
if (!(tp.t_data->t_infomask & HEAP_UPDATED) ||
tp.t_data->t_xmin < XmaxRecent)
break;
/* Well, try to find tuple with old row version */
for (;;)
{
Buffer Pbuf;
Page Ppage;
ItemId Pitemid;
HeapTupleData Ptp;
VTupleLinkData vtld,
*vtlp;
vtld.new_tid = tp.t_self;
vtlp = (VTupleLink)
vac_find_eq((void *) (vacrelstats->vtlinks),
vacrelstats->num_vtlinks,
sizeof(VTupleLinkData),
(void *) &vtld,
vac_cmp_vtlinks);
if (vtlp == NULL)
elog(ERROR, "Parent tuple was not found");
tp.t_self = vtlp->this_tid;
Pbuf = ReadBuffer(onerel,
ItemPointerGetBlockNumber(&(tp.t_self)));
Ppage = BufferGetPage(Pbuf);
Pitemid = PageGetItemId(Ppage,
ItemPointerGetOffsetNumber(&(tp.t_self)));
if (!ItemIdIsUsed(Pitemid))
elog(ERROR, "Parent itemid marked as unused");
Ptp.t_datamcxt = NULL;
Ptp.t_data = (HeapTupleHeader) PageGetItem(Ppage, Pitemid);
Assert(ItemPointerEquals(&(vtld.new_tid),
&(Ptp.t_data->t_ctid)));
/*
* Read above about cases when
* !ItemIdIsUsed(Citemid) (child item is
* removed)... Due to the fact that at the moment
* we don't remove unuseful part of update-chain,
* it's possible to get too old parent row here.
* Like as in the case which caused this problem,
* we stop shrinking here. I could try to find
* real parent row but want not to do it because
* of real solution will be implemented anyway,
* latter, and we are too close to 6.5 release. -
* vadim 06/11/99
*/
if (Ptp.t_data->t_xmax != tp.t_data->t_xmin)
{
if (freeCbuf)
ReleaseBuffer(Cbuf);
freeCbuf = false;
ReleaseBuffer(Pbuf);
for (i = 0; i < num_vtmove; i++)
{
Assert(vtmove[i].vacpage->offsets_used > 0);
(vtmove[i].vacpage->offsets_used)--;
}
num_vtmove = 0;
elog(NOTICE, "Too old parent tuple found - can't continue repair_frag");
break;
}
#ifdef NOT_USED /* I'm not sure that this will wotk
* properly... */
/*
* If this tuple is updated version of row and it
* was created by the same transaction then no one
* is interested in this tuple - mark it as
* removed.
*/
if (Ptp.t_data->t_infomask & HEAP_UPDATED &&
Ptp.t_data->t_xmin == Ptp.t_data->t_xmax)
{
TransactionIdStore(myXID,
(TransactionId *) &(Ptp.t_data->t_cmin));
Ptp.t_data->t_infomask &=
~(HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID | HEAP_MOVED_IN);
Ptp.t_data->t_infomask |= HEAP_MOVED_OFF;
WriteBuffer(Pbuf);
continue;
}
#endif
tp.t_datamcxt = Ptp.t_datamcxt;
tp.t_data = Ptp.t_data;
tlen = tp.t_len = ItemIdGetLength(Pitemid);
if (freeCbuf)
ReleaseBuffer(Cbuf);
Cbuf = Pbuf;
freeCbuf = true;
break;
}
if (num_vtmove == 0)
break;
}
if (freeCbuf)
ReleaseBuffer(Cbuf);
if (num_vtmove == 0) /* chain can't be moved */
{
pfree(vtmove);
break;
}
ItemPointerSetInvalid(&Ctid);
for (ti = 0; ti < num_vtmove; ti++)
{
VacPage destvacpage = vtmove[ti].vacpage;
/* Get tuple from chain */
tuple.t_self = vtmove[ti].tid;
Cbuf = ReadBuffer(onerel,
ItemPointerGetBlockNumber(&(tuple.t_self)));
Cpage = BufferGetPage(Cbuf);
Citemid = PageGetItemId(Cpage,
ItemPointerGetOffsetNumber(&(tuple.t_self)));
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(Cpage, Citemid);
tuple_len = tuple.t_len = ItemIdGetLength(Citemid);
/* Get page to move in */
cur_buffer = ReadBuffer(onerel, destvacpage->blkno);
/*
* We should LockBuffer(cur_buffer) but don't, at the
* moment. If you'll do LockBuffer then UNLOCK it
* before index_insert: unique btree-s call heap_fetch
* to get t_infomask of inserted heap tuple !!!
*/
ToPage = BufferGetPage(cur_buffer);
/*
* If this page was not used before - clean it.
*
* This path is different from the other callers of
* vacuum_page, because we have already incremented the
* vacpage's offsets_used field to account for the
* tuple(s) we expect to move onto the page. Therefore
* vacuum_page's check for offsets_used == 0 is
* wrong. But since that's a good debugging check for
* all other callers, we work around it here rather
* than remove it.
*/
if (!PageIsEmpty(ToPage) && vtmove[ti].cleanVpd)
{
int sv_offsets_used = destvacpage->offsets_used;
destvacpage->offsets_used = 0;
vacuum_page(ToPage, destvacpage);
destvacpage->offsets_used = sv_offsets_used;
}
heap_copytuple_with_tuple(&tuple, &newtup);
RelationInvalidateHeapTuple(onerel, &tuple);
TransactionIdStore(myXID, (TransactionId *) &(newtup.t_data->t_cmin));
newtup.t_data->t_infomask &=
~(HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID | HEAP_MOVED_OFF);
newtup.t_data->t_infomask |= HEAP_MOVED_IN;
newoff = PageAddItem(ToPage, (Item) newtup.t_data, tuple_len,
InvalidOffsetNumber, LP_USED);
if (newoff == InvalidOffsetNumber)
{
elog(ERROR, "moving chain: failed to add item with len = %u to page %u",
tuple_len, destvacpage->blkno);
}
newitemid = PageGetItemId(ToPage, newoff);
pfree(newtup.t_data);
newtup.t_datamcxt = NULL;
newtup.t_data = (HeapTupleHeader) PageGetItem(ToPage, newitemid);
ItemPointerSet(&(newtup.t_self), destvacpage->blkno, newoff);
if (((int) destvacpage->blkno) > last_move_dest_block)
last_move_dest_block = destvacpage->blkno;
/*
* Set t_ctid pointing to itself for last tuple in
* chain and to next tuple in chain otherwise.
*/
if (!ItemPointerIsValid(&Ctid))
newtup.t_data->t_ctid = newtup.t_self;
else
newtup.t_data->t_ctid = Ctid;
Ctid = newtup.t_self;
TransactionIdStore(myXID, (TransactionId *) &(tuple.t_data->t_cmin));
tuple.t_data->t_infomask &=
~(HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID | HEAP_MOVED_IN);
tuple.t_data->t_infomask |= HEAP_MOVED_OFF;
num_moved++;
/*
* Remember that we moved tuple from the current page
* (corresponding index tuple will be cleaned).
*/
if (Cbuf == buf)
vacpage->offsets[vacpage->offsets_free++] =
ItemPointerGetOffsetNumber(&(tuple.t_self));
else
keep_tuples++;
if (Irel != (Relation *) NULL)
{
/*
* XXX using CurrentMemoryContext here means
* intra-vacuum memory leak for functional indexes.
* Should fix someday.
*
* XXX This code fails to handle partial indexes!
* Probably should change it to use ExecOpenIndices.
*/
for (i = 0; i < nindices; i++)
{
FormIndexDatum(indexInfo[i],
&newtup,
tupdesc,
CurrentMemoryContext,
idatum,
inulls);
iresult = index_insert(Irel[i],
idatum,
inulls,
&newtup.t_self,
onerel);
if (iresult)
pfree(iresult);
}
}
WriteBuffer(cur_buffer);
if (Cbuf == buf)
ReleaseBuffer(Cbuf);
else
WriteBuffer(Cbuf);
}
cur_buffer = InvalidBuffer;
pfree(vtmove);
chain_tuple_moved = true;
continue;
}
/* try to find new page for this tuple */
if (cur_buffer == InvalidBuffer ||
!enough_space(cur_page, tuple_len))
{
if (cur_buffer != InvalidBuffer)
{
WriteBuffer(cur_buffer);
cur_buffer = InvalidBuffer;
/*
* If previous target page is now too full to add *any*
* tuple to it, remove it from fraged_pages.
*/
if (!enough_space(cur_page, vacrelstats->min_tlen))
{
Assert(num_fraged_pages > cur_item);
memmove(fraged_pages->pagedesc + cur_item,
fraged_pages->pagedesc + cur_item + 1,
sizeof(VacPage) * (num_fraged_pages - cur_item - 1));
num_fraged_pages--;
}
}
for (i = 0; i < num_fraged_pages; i++)
{
if (enough_space(fraged_pages->pagedesc[i], tuple_len))
break;
}
if (i == num_fraged_pages)
break; /* can't move item anywhere */
cur_item = i;
cur_page = fraged_pages->pagedesc[cur_item];
cur_buffer = ReadBuffer(onerel, cur_page->blkno);
ToPage = BufferGetPage(cur_buffer);
/* if this page was not used before - clean it */
if (!PageIsEmpty(ToPage) && cur_page->offsets_used == 0)
vacuum_page(ToPage, cur_page);
}
/* copy tuple */
heap_copytuple_with_tuple(&tuple, &newtup);
RelationInvalidateHeapTuple(onerel, &tuple);
/*
* Mark new tuple as moved_in by vacuum and store vacuum XID
* in t_cmin !!!
*/
TransactionIdStore(myXID, (TransactionId *) &(newtup.t_data->t_cmin));
newtup.t_data->t_infomask &=
~(HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID | HEAP_MOVED_OFF);
newtup.t_data->t_infomask |= HEAP_MOVED_IN;
/* add tuple to the page */
newoff = PageAddItem(ToPage, (Item) newtup.t_data, tuple_len,
InvalidOffsetNumber, LP_USED);
if (newoff == InvalidOffsetNumber)
{
elog(ERROR, "\
failed to add item with len = %u to page %u (free space %u, nusd %u, noff %u)",
tuple_len, cur_page->blkno, cur_page->free,
cur_page->offsets_used, cur_page->offsets_free);
}
newitemid = PageGetItemId(ToPage, newoff);
pfree(newtup.t_data);
newtup.t_datamcxt = NULL;
newtup.t_data = (HeapTupleHeader) PageGetItem(ToPage, newitemid);
ItemPointerSet(&(newtup.t_data->t_ctid), cur_page->blkno, newoff);
newtup.t_self = newtup.t_data->t_ctid;
/*
* Mark old tuple as moved_off by vacuum and store vacuum XID
* in t_cmin !!!
*/
TransactionIdStore(myXID, (TransactionId *) &(tuple.t_data->t_cmin));
tuple.t_data->t_infomask &=
~(HEAP_XMIN_COMMITTED | HEAP_XMIN_INVALID | HEAP_MOVED_IN);
tuple.t_data->t_infomask |= HEAP_MOVED_OFF;
cur_page->offsets_used++;
num_moved++;
cur_page->free = ((PageHeader) ToPage)->pd_upper - ((PageHeader) ToPage)->pd_lower;
if (((int) cur_page->blkno) > last_move_dest_block)
last_move_dest_block = cur_page->blkno;
vacpage->offsets[vacpage->offsets_free++] = offnum;
/* insert index' tuples if needed */
if (Irel != (Relation *) NULL)
{
/*
* XXX using CurrentMemoryContext here means
* intra-vacuum memory leak for functional indexes.
* Should fix someday.
*
* XXX This code fails to handle partial indexes!
* Probably should change it to use ExecOpenIndices.
*/
for (i = 0; i < nindices; i++)
{
FormIndexDatum(indexInfo[i],
&newtup,
tupdesc,
CurrentMemoryContext,
idatum,
inulls);
iresult = index_insert(Irel[i],
idatum,
inulls,
&newtup.t_self,
onerel);
if (iresult)
pfree(iresult);
}
}
} /* walk along page */
if (offnum < maxoff && keep_tuples > 0)
{
OffsetNumber off;
for (off = OffsetNumberNext(offnum);
off <= maxoff;
off = OffsetNumberNext(off))
{
itemid = PageGetItemId(page, off);
if (!ItemIdIsUsed(itemid))
continue;
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
if (tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED)
continue;
if ((TransactionId) tuple.t_data->t_cmin != myXID)
elog(ERROR, "Invalid XID in t_cmin (4)");
if (tuple.t_data->t_infomask & HEAP_MOVED_IN)
elog(ERROR, "HEAP_MOVED_IN was not expected (2)");
if (tuple.t_data->t_infomask & HEAP_MOVED_OFF)
{
/* some chains was moved while */
if (chain_tuple_moved)
{ /* cleaning this page */
Assert(vacpage->offsets_free > 0);
for (i = 0; i < vacpage->offsets_free; i++)
{
if (vacpage->offsets[i] == off)
break;
}
if (i >= vacpage->offsets_free) /* not found */
{
vacpage->offsets[vacpage->offsets_free++] = off;
Assert(keep_tuples > 0);
keep_tuples--;
}
}
else
{
vacpage->offsets[vacpage->offsets_free++] = off;
Assert(keep_tuples > 0);
keep_tuples--;
}
}
}
}
if (vacpage->offsets_free > 0) /* some tuples were moved */
{
if (chain_tuple_moved) /* else - they are ordered */
{
qsort((char *) (vacpage->offsets), vacpage->offsets_free,
sizeof(OffsetNumber), vac_cmp_offno);
}
reap_page(&Nvacpagelist, vacpage);
WriteBuffer(buf);
}
else if (dowrite)
WriteBuffer(buf);
else
ReleaseBuffer(buf);
if (offnum <= maxoff)
break; /* some item(s) left */
} /* walk along relation */
blkno++; /* new number of blocks */
if (cur_buffer != InvalidBuffer)
{
Assert(num_moved > 0);
WriteBuffer(cur_buffer);
}
if (num_moved > 0)
{
/*
* We have to commit our tuple' movings before we'll truncate
* relation, but we shouldn't lose our locks. And so - quick hack:
* flush buffers and record status of current transaction as
* committed, and continue. - vadim 11/13/96
*/
FlushBufferPool();
TransactionIdCommit(myXID);
FlushBufferPool();
}
/*
* Clean uncleaned reaped pages from vacuum_pages list list and set
* xmin committed for inserted tuples
*/
checked_moved = 0;
for (i = 0, curpage = vacuum_pages->pagedesc; i < vacuumed_pages; i++, curpage++)
{
Assert((*curpage)->blkno < (BlockNumber) blkno);
buf = ReadBuffer(onerel, (*curpage)->blkno);
page = BufferGetPage(buf);
if ((*curpage)->offsets_used == 0) /* this page was not used */
{
if (!PageIsEmpty(page))
vacuum_page(page, *curpage);
}
else
/* this page was used */
{
num_tuples = 0;
max_offset = PageGetMaxOffsetNumber(page);
for (newoff = FirstOffsetNumber;
newoff <= max_offset;
newoff = OffsetNumberNext(newoff))
{
itemid = PageGetItemId(page, newoff);
if (!ItemIdIsUsed(itemid))
continue;
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
if ((TransactionId) tuple.t_data->t_cmin != myXID)
elog(ERROR, "Invalid XID in t_cmin (2)");
if (tuple.t_data->t_infomask & HEAP_MOVED_IN)
{
tuple.t_data->t_infomask |= HEAP_XMIN_COMMITTED;
num_tuples++;
}
else if (tuple.t_data->t_infomask & HEAP_MOVED_OFF)
tuple.t_data->t_infomask |= HEAP_XMIN_INVALID;
else
elog(ERROR, "HEAP_MOVED_OFF/HEAP_MOVED_IN was expected");
}
}
Assert((*curpage)->offsets_used == num_tuples);
checked_moved += num_tuples;
}
WriteBuffer(buf);
}
Assert(num_moved == checked_moved);
elog(MESSAGE_LEVEL, "Rel %s: Pages: %u --> %u; Tuple(s) moved: %u. %s",
RelationGetRelationName(onerel),
nblocks, blkno, num_moved,
show_rusage(&ru0));
if (Nvacpagelist.num_pages > 0)
{
/* vacuum indices again if needed */
if (Irel != (Relation *) NULL)
{
VacPage *vpleft,
*vpright,
vpsave;
/* re-sort Nvacpagelist.pagedesc */
for (vpleft = Nvacpagelist.pagedesc,
vpright = Nvacpagelist.pagedesc + Nvacpagelist.num_pages - 1;
vpleft < vpright; vpleft++, vpright--)
{
vpsave = *vpleft;
*vpleft = *vpright;
*vpright = vpsave;
}
Assert(keep_tuples >= 0);
for (i = 0; i < nindices; i++)
vacuum_index(&Nvacpagelist, Irel[i],
vacrelstats->num_tuples, keep_tuples);
}
/* clean moved tuples from last page in Nvacpagelist list */
if (vacpage->blkno == (BlockNumber) (blkno - 1) &&
vacpage->offsets_free > 0)
{
buf = ReadBuffer(onerel, vacpage->blkno);
page = BufferGetPage(buf);
num_tuples = 0;
for (offnum = FirstOffsetNumber;
offnum <= maxoff;
offnum = OffsetNumberNext(offnum))
{
itemid = PageGetItemId(page, offnum);
if (!ItemIdIsUsed(itemid))
continue;
tuple.t_datamcxt = NULL;
tuple.t_data = (HeapTupleHeader) PageGetItem(page, itemid);
if (!(tuple.t_data->t_infomask & HEAP_XMIN_COMMITTED))
{
if ((TransactionId) tuple.t_data->t_cmin != myXID)
elog(ERROR, "Invalid XID in t_cmin (3)");
if (tuple.t_data->t_infomask & HEAP_MOVED_OFF)
{
itemid->lp_flags &= ~LP_USED;
num_tuples++;
}
else
elog(ERROR, "HEAP_MOVED_OFF was expected (2)");
}
}
Assert(vacpage->offsets_free == num_tuples);
PageRepairFragmentation(page);
WriteBuffer(buf);
}
/* now - free new list of reaped pages */
curpage = Nvacpagelist.pagedesc;
for (i = 0; i < Nvacpagelist.num_pages; i++, curpage++)
pfree(*curpage);
pfree(Nvacpagelist.pagedesc);
}
/* truncate relation, after flushing any dirty pages out to disk */
if (blkno < nblocks)
{
i = FlushRelationBuffers(onerel, blkno);
if (i < 0)
elog(FATAL, "VACUUM (repair_frag): FlushRelationBuffers returned %d", i);
blkno = smgrtruncate(DEFAULT_SMGR, onerel, blkno);
Assert(blkno >= 0);
vacrelstats->num_pages = blkno; /* set new number of blocks */
}
if (Irel != (Relation *) NULL) /* pfree index' allocations */
{
close_indices(nindices, Irel);
pfree(indexInfo);
}
pfree(vacpage);
if (vacrelstats->vtlinks != NULL)
pfree(vacrelstats->vtlinks);
}
/*
* vacuum_heap() -- free dead tuples
*
* This routine marks dead tuples as unused and truncates relation
* if there are "empty" end-blocks.
*/
static void
vacuum_heap(VRelStats *vacrelstats, Relation onerel, VacPageList vacuum_pages)
{
Buffer buf;
Page page;
VacPage *vacpage;
int nblocks;
int i;
nblocks = vacuum_pages->num_pages;
nblocks -= vacuum_pages->empty_end_pages; /* nothing to do with
* them */
for (i = 0, vacpage = vacuum_pages->pagedesc; i < nblocks; i++, vacpage++)
{
if ((*vacpage)->offsets_free > 0)
{
buf = ReadBuffer(onerel, (*vacpage)->blkno);
page = BufferGetPage(buf);
vacuum_page(page, *vacpage);
WriteBuffer(buf);
}
}
/* truncate relation if there are some empty end-pages */
if (vacuum_pages->empty_end_pages > 0)
{
Assert(vacrelstats->num_pages >= vacuum_pages->empty_end_pages);
nblocks = vacrelstats->num_pages - vacuum_pages->empty_end_pages;
elog(MESSAGE_LEVEL, "Rel %s: Pages: %u --> %u.",
RelationGetRelationName(onerel),
vacrelstats->num_pages, nblocks);
/*
* We have to flush "empty" end-pages (if changed, but who knows
* it) before truncation
*
* XXX is FlushBufferPool() still needed here?
*/
FlushBufferPool();
i = FlushRelationBuffers(onerel, nblocks);
if (i < 0)
elog(FATAL, "VACUUM (vacuum_heap): FlushRelationBuffers returned %d", i);
nblocks = smgrtruncate(DEFAULT_SMGR, onerel, nblocks);
Assert(nblocks >= 0);
vacrelstats->num_pages = nblocks; /* set new number of
* blocks */
}
}
/*
* vacuum_page() -- free dead tuples on a page
* and repair its fragmentation.
*/
static void
vacuum_page(Page page, VacPage vacpage)
{
ItemId itemid;
int i;
/* There shouldn't be any tuples moved onto the page yet! */
Assert(vacpage->offsets_used == 0);
for (i = 0; i < vacpage->offsets_free; i++)
{
itemid = &(((PageHeader) page)->pd_linp[vacpage->offsets[i] - 1]);
itemid->lp_flags &= ~LP_USED;
}
PageRepairFragmentation(page);
}
/*
* _scan_index() -- scan one index relation to update statistic.
*
*/
static void
scan_index(Relation indrel, int num_tuples)
{
RetrieveIndexResult res;
IndexScanDesc iscan;
int nitups;
int nipages;
struct rusage ru0;
getrusage(RUSAGE_SELF, &ru0);
/* walk through the entire index */
iscan = index_beginscan(indrel, false, 0, (ScanKey) NULL);
nitups = 0;
while ((res = index_getnext(iscan, ForwardScanDirection))
!= (RetrieveIndexResult) NULL)
{
nitups++;
pfree(res);
}
index_endscan(iscan);
/* now update statistics in pg_class */
nipages = RelationGetNumberOfBlocks(indrel);
update_relstats(RelationGetRelid(indrel), nipages, nitups, false, NULL);
elog(MESSAGE_LEVEL, "Index %s: Pages %u; Tuples %u. %s",
RelationGetRelationName(indrel), nipages, nitups,
show_rusage(&ru0));
if (nitups != num_tuples)
elog(NOTICE, "Index %s: NUMBER OF INDEX' TUPLES (%u) IS NOT THE SAME AS HEAP' (%u).\
\n\tRecreate the index.",
RelationGetRelationName(indrel), nitups, num_tuples);
}
/*
* vacuum_index() -- vacuum one index relation.
*
* Vpl is the VacPageList of the heap we're currently vacuuming.
* It's locked. Indrel is an index relation on the vacuumed heap.
* We don't set locks on the index relation here, since the indexed
* access methods support locking at different granularities.
* We let them handle it.
*
* Finally, we arrange to update the index relation's statistics in
* pg_class.
*/
static void
vacuum_index(VacPageList vacpagelist, Relation indrel, int num_tuples, int keep_tuples)
{
RetrieveIndexResult res;
IndexScanDesc iscan;
ItemPointer heapptr;
int tups_vacuumed;
int num_index_tuples;
int num_pages;
VacPage vp;
struct rusage ru0;
getrusage(RUSAGE_SELF, &ru0);
/* walk through the entire index */
iscan = index_beginscan(indrel, false, 0, (ScanKey) NULL);
tups_vacuumed = 0;
num_index_tuples = 0;
while ((res = index_getnext(iscan, ForwardScanDirection))
!= (RetrieveIndexResult) NULL)
{
heapptr = &res->heap_iptr;
if ((vp = tid_reaped(heapptr, vacpagelist)) != (VacPage) NULL)
{
#ifdef NOT_USED
elog(DEBUG, "<%x,%x> -> <%x,%x>",
ItemPointerGetBlockNumber(&(res->index_iptr)),
ItemPointerGetOffsetNumber(&(res->index_iptr)),
ItemPointerGetBlockNumber(&(res->heap_iptr)),
ItemPointerGetOffsetNumber(&(res->heap_iptr)));
#endif
if (vp->offsets_free == 0)
{
elog(NOTICE, "Index %s: pointer to EmptyPage (blk %u off %u) - fixing",
RelationGetRelationName(indrel),
vp->blkno, ItemPointerGetOffsetNumber(heapptr));
}
++tups_vacuumed;
index_delete(indrel, &res->index_iptr);
}
else
num_index_tuples++;
pfree(res);
}
index_endscan(iscan);
/* now update statistics in pg_class */
num_pages = RelationGetNumberOfBlocks(indrel);
update_relstats(RelationGetRelid(indrel), num_pages, num_index_tuples, false, NULL);
elog(MESSAGE_LEVEL, "Index %s: Pages %u; Tuples %u: Deleted %u. %s",
RelationGetRelationName(indrel), num_pages,
num_index_tuples - keep_tuples, tups_vacuumed,
show_rusage(&ru0));
if (num_index_tuples != num_tuples + keep_tuples)
elog(NOTICE, "Index %s: NUMBER OF INDEX' TUPLES (%u) IS NOT THE SAME AS HEAP' (%u).\
\n\tRecreate the index.",
RelationGetRelationName(indrel), num_index_tuples, num_tuples);
}
/*
* tid_reaped() -- is a particular tid reaped?
*
* vacpagelist->VacPage_array is sorted in right order.
*/
static VacPage
tid_reaped(ItemPointer itemptr, VacPageList vacpagelist)
{
OffsetNumber ioffno;
OffsetNumber *voff;
VacPage vp,
*vpp;
VacPageData vacpage;
vacpage.blkno = ItemPointerGetBlockNumber(itemptr);
ioffno = ItemPointerGetOffsetNumber(itemptr);
vp = &vacpage;
vpp = (VacPage *) vac_find_eq((void *) (vacpagelist->pagedesc),
vacpagelist->num_pages, sizeof(VacPage), (void *) &vp,
vac_cmp_blk);
if (vpp == (VacPage *) NULL)
return (VacPage) NULL;
vp = *vpp;
/* ok - we are on true page */
if (vp->offsets_free == 0)
{ /* this is EmptyPage !!! */
return vp;
}
voff = (OffsetNumber *) vac_find_eq((void *) (vp->offsets),
vp->offsets_free, sizeof(OffsetNumber), (void *) &ioffno,
vac_cmp_offno);
if (voff == (OffsetNumber *) NULL)
return (VacPage) NULL;
return vp;
}
/*
* update_relstats() -- update statistics for one relation
*
* Statistics are stored in several places: the pg_class row for the
* relation has stats about the whole relation, the pg_attribute rows
* for each attribute store "disbursion", and there is a pg_statistic
* row for each (non-system) attribute. (Disbursion probably ought to
* be moved to pg_statistic, but it's not worth doing unless there's
* another reason to have to change pg_attribute.) Disbursion and
* pg_statistic values are only updated by VACUUM ANALYZE, but we
* always update the stats in pg_class.
*
* This routine works for both index and heap relation entries in
* pg_class. We violate no-overwrite semantics here by storing new
* values for the statistics columns directly into the pg_class
* tuple that's already on the page. The reason for this is that if
* we updated these tuples in the usual way, vacuuming pg_class itself
* wouldn't work very well --- by the time we got done with a vacuum
* cycle, most of the tuples in pg_class would've been obsoleted.
* Updating pg_class's own statistics would be especially tricky.
* Of course, this only works for fixed-size never-null columns, but
* these are.
*/
static void
update_relstats(Oid relid, int num_pages, int num_tuples, bool hasindex,
VRelStats *vacrelstats)
{
Relation rd;
HeapTupleData rtup;
HeapTuple ctup;
Form_pg_class pgcform;
Buffer buffer;
/*
* update number of tuples and number of pages in pg_class
*/
rd = heap_openr(RelationRelationName, RowExclusiveLock);
ctup = SearchSysCacheTupleCopy(RELOID,
ObjectIdGetDatum(relid),
0, 0, 0);
if (!HeapTupleIsValid(ctup))
elog(ERROR, "pg_class entry for relid %u vanished during vacuuming",
relid);
/* get the buffer cache tuple */
rtup.t_self = ctup->t_self;
heap_fetch(rd, SnapshotNow, &rtup, &buffer);
heap_freetuple(ctup);
/* overwrite the existing statistics in the tuple */
pgcform = (Form_pg_class) GETSTRUCT(&rtup);
pgcform->reltuples = num_tuples;
pgcform->relpages = num_pages;
pgcform->relhasindex = hasindex;
/* invalidate the tuple in the cache and write the buffer */
RelationInvalidateHeapTuple(rd, &rtup);
WriteBuffer(buffer);
heap_close(rd, RowExclusiveLock);
}
/*
* reap_page() -- save a page on the array of reaped pages.
*
* As a side effect of the way that the vacuuming loop for a given
* relation works, higher pages come after lower pages in the array
* (and highest tid on a page is last).
*/
static void
reap_page(VacPageList vacpagelist, VacPage vacpage)
{
VacPage newvacpage;
/* allocate a VacPageData entry */
newvacpage = (VacPage) palloc(sizeof(VacPageData) + vacpage->offsets_free * sizeof(OffsetNumber));
/* fill it in */
if (vacpage->offsets_free > 0)
memmove(newvacpage->offsets, vacpage->offsets, vacpage->offsets_free * sizeof(OffsetNumber));
newvacpage->blkno = vacpage->blkno;
newvacpage->free = vacpage->free;
newvacpage->offsets_used = vacpage->offsets_used;
newvacpage->offsets_free = vacpage->offsets_free;
/* insert this page into vacpagelist list */
vpage_insert(vacpagelist, newvacpage);
}
static void
vpage_insert(VacPageList vacpagelist, VacPage vpnew)
{
#define PG_NPAGEDESC 1024
/* allocate a VacPage entry if needed */
if (vacpagelist->num_pages == 0)
{
vacpagelist->pagedesc = (VacPage *) palloc(PG_NPAGEDESC * sizeof(VacPage));
vacpagelist->num_allocated_pages = PG_NPAGEDESC;
}
else if (vacpagelist->num_pages >= vacpagelist->num_allocated_pages)
{
vacpagelist->num_allocated_pages *= 2;
vacpagelist->pagedesc = (VacPage *) repalloc(vacpagelist->pagedesc, vacpagelist->num_allocated_pages * sizeof(VacPage));
}
vacpagelist->pagedesc[vacpagelist->num_pages] = vpnew;
(vacpagelist->num_pages)++;
}
static void *
vac_find_eq(void *bot, int nelem, int size, void *elm,
int (*compar) (const void *, const void *))
{
int res;
int last = nelem - 1;
int celm = nelem / 2;
bool last_move,
first_move;
last_move = first_move = true;
for (;;)
{
if (first_move == true)
{
res = compar(bot, elm);
if (res > 0)
return NULL;
if (res == 0)
return bot;
first_move = false;
}
if (last_move == true)
{
res = compar(elm, (void *) ((char *) bot + last * size));
if (res > 0)
return NULL;
if (res == 0)
return (void *) ((char *) bot + last * size);
last_move = false;
}
res = compar(elm, (void *) ((char *) bot + celm * size));
if (res == 0)
return (void *) ((char *) bot + celm * size);
if (res < 0)
{
if (celm == 0)
return NULL;
last = celm - 1;
celm = celm / 2;
last_move = true;
continue;
}
if (celm == last)
return NULL;
last = last - celm - 1;
bot = (void *) ((char *) bot + (celm + 1) * size);
celm = (last + 1) / 2;
first_move = true;
}
}
static int
vac_cmp_blk(const void *left, const void *right)
{
BlockNumber lblk,
rblk;
lblk = (*((VacPage *) left))->blkno;
rblk = (*((VacPage *) right))->blkno;
if (lblk < rblk)
return -1;
if (lblk == rblk)
return 0;
return 1;
}
static int
vac_cmp_offno(const void *left, const void *right)
{
if (*(OffsetNumber *) left < *(OffsetNumber *) right)
return -1;
if (*(OffsetNumber *) left == *(OffsetNumber *) right)
return 0;
return 1;
}
static int
vac_cmp_vtlinks(const void *left, const void *right)
{
if (((VTupleLink) left)->new_tid.ip_blkid.bi_hi <
((VTupleLink) right)->new_tid.ip_blkid.bi_hi)
return -1;
if (((VTupleLink) left)->new_tid.ip_blkid.bi_hi >
((VTupleLink) right)->new_tid.ip_blkid.bi_hi)
return 1;
/* bi_hi-es are equal */
if (((VTupleLink) left)->new_tid.ip_blkid.bi_lo <
((VTupleLink) right)->new_tid.ip_blkid.bi_lo)
return -1;
if (((VTupleLink) left)->new_tid.ip_blkid.bi_lo >
((VTupleLink) right)->new_tid.ip_blkid.bi_lo)
return 1;
/* bi_lo-es are equal */
if (((VTupleLink) left)->new_tid.ip_posid <
((VTupleLink) right)->new_tid.ip_posid)
return -1;
if (((VTupleLink) left)->new_tid.ip_posid >
((VTupleLink) right)->new_tid.ip_posid)
return 1;
return 0;
}
static void
get_indices(Relation relation, int *nindices, Relation **Irel)
{
List *indexoidlist,
*indexoidscan;
int i;
indexoidlist = RelationGetIndexList(relation);
*nindices = length(indexoidlist);
if (*nindices > 0)
*Irel = (Relation *) palloc(*nindices * sizeof(Relation));
else
*Irel = NULL;
i = 0;
foreach(indexoidscan, indexoidlist)
{
Oid indexoid = lfirsti(indexoidscan);
(*Irel)[i] = index_open(indexoid);
i++;
}
freeList(indexoidlist);
}
static void
close_indices(int nindices, Relation *Irel)
{
if (Irel == (Relation *) NULL)
return;
while (nindices--)
index_close(Irel[nindices]);
pfree(Irel);
}
/*
* Obtain IndexInfo data for each index on the rel
*/
static IndexInfo **
get_index_desc(Relation onerel, int nindices, Relation *Irel)
{
IndexInfo **indexInfo;
int i;
HeapTuple cachetuple;
indexInfo = (IndexInfo **) palloc(nindices * sizeof(IndexInfo *));
for (i = 0; i < nindices; i++)
{
cachetuple = SearchSysCacheTuple(INDEXRELID,
ObjectIdGetDatum(RelationGetRelid(Irel[i])),
0, 0, 0);
if (!HeapTupleIsValid(cachetuple))
elog(ERROR, "get_index_desc: index %u not found",
RelationGetRelid(Irel[i]));
indexInfo[i] = BuildIndexInfo(cachetuple);
}
return indexInfo;
}
static bool
enough_space(VacPage vacpage, Size len)
{
len = MAXALIGN(len);
if (len > vacpage->free)
return false;
if (vacpage->offsets_used < vacpage->offsets_free) /* there are free
* itemid(s) */
return true; /* and len <= free_space */
/* ok. noff_usd >= noff_free and so we'll have to allocate new itemid */
if (len + MAXALIGN(sizeof(ItemIdData)) <= vacpage->free)
return true;
return false;
}
/*
* Compute elapsed time since ru0 usage snapshot, and format into
* a displayable string. Result is in a static string, which is
* tacky, but no one ever claimed that the Postgres backend is
* threadable...
*/
static char *
show_rusage(struct rusage * ru0)
{
static char result[64];
struct rusage ru1;
getrusage(RUSAGE_SELF, &ru1);
if (ru1.ru_stime.tv_usec < ru0->ru_stime.tv_usec)
{
ru1.ru_stime.tv_sec--;
ru1.ru_stime.tv_usec += 1000000;
}
if (ru1.ru_utime.tv_usec < ru0->ru_utime.tv_usec)
{
ru1.ru_utime.tv_sec--;
ru1.ru_utime.tv_usec += 1000000;
}
snprintf(result, sizeof(result),
"CPU %d.%02ds/%d.%02du sec.",
(int) (ru1.ru_stime.tv_sec - ru0->ru_stime.tv_sec),
(int) (ru1.ru_stime.tv_usec - ru0->ru_stime.tv_usec) / 10000,
(int) (ru1.ru_utime.tv_sec - ru0->ru_utime.tv_sec),
(int) (ru1.ru_utime.tv_usec - ru0->ru_utime.tv_usec) / 10000);
return result;
}
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