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Allow vacuum to perform analyze with shared lock. Update cvs manual.

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This commit is contained in:
Bruce Momjian 2000-05-29 15:44:55 +00:00
parent 091126fa28
commit 659f79be7a
3 changed files with 446 additions and 383 deletions
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6
doc/src/sgml/cvs.sgml
View File

@ -1,5 +1,5 @@
<!-- <!--
$Header: /cvsroot/pgsql/doc/src/sgml/cvs.sgml,v 1.8 2000/05/02 20:01:51 thomas Exp $ $Header: /cvsroot/pgsql/doc/src/sgml/cvs.sgml,v 1.9 2000/05/29 15:44:54 momjian Exp $
CVS code repository CVS code repository
Thomas Lockhart Thomas Lockhart
--> -->
@ -184,7 +184,7 @@ cvs commit
Do an initial login to the <productname>CVS</productname> server: Do an initial login to the <productname>CVS</productname> server:
<programlisting> <programlisting>
$ cvs -d :pserver:anoncvs@postgresql.org:/usr/local/cvsroot login $ cvs -d :pserver:anoncvs@postgresql.org:/home/projects/pgsql/cvsroot login
</programlisting> </programlisting>
You will be prompted for a password; enter '<literal>postgresql</literal>'. You will be prompted for a password; enter '<literal>postgresql</literal>'.
@ -197,7 +197,7 @@ $ cvs -d :pserver:anoncvs@postgresql.org:/usr/local/cvsroot login
<para> <para>
Fetch the <productname>Postgres</productname> sources: Fetch the <productname>Postgres</productname> sources:
<programlisting> <programlisting>
cvs -z3 -d :pserver:anoncvs@postgresql.org:/usr/local/cvsroot co -P pgsql cvs -z3 -d :pserver:anoncvs@postgresql.org:/home/projects/pgsql/cvsroot co -P pgsql
</programlisting> </programlisting>
which installs the <productname>Postgres</productname> sources into a which installs the <productname>Postgres</productname> sources into a

819
src/backend/commands/vacuum.c
View File

@ -8,7 +8,7 @@
* *
* *
* IDENTIFICATION * IDENTIFICATION
* $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.151 2000/05/29 01:55:07 momjian Exp $ * $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.152 2000/05/29 15:44:55 momjian Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
@ -77,15 +77,17 @@ static void vacuum_shutdown(void);
static void vac_vacuum(NameData *VacRelP, bool analyze, List *va_cols); static void vac_vacuum(NameData *VacRelP, bool analyze, List *va_cols);
static VRelList getrels(NameData *VacRelP); static VRelList getrels(NameData *VacRelP);
static void vacuum_rel(Oid relid, bool analyze, List *va_cols); static void vacuum_rel(Oid relid, bool analyze, List *va_cols);
static void analyze_rel(Oid relid, List *va_cols);
static void scan_heap(VRelStats *vacrelstats, Relation onerel, VPageList vacuum_pages, VPageList fraged_pages); static void scan_heap(VRelStats *vacrelstats, Relation onerel, VPageList vacuum_pages, VPageList fraged_pages);
static void repair_frag(VRelStats *vacrelstats, Relation onerel, VPageList vacuum_pages, VPageList fraged_pages, int nindices, Relation *Irel); static void repair_frag(VRelStats *vacrelstats, Relation onerel, VPageList vacuum_pages, VPageList fraged_pages, int nindices, Relation *Irel);
static void vacuum_heap(VRelStats *vacrelstats, Relation onerel, VPageList vpl); static void vacuum_heap(VRelStats *vacrelstats, Relation onerel, VPageList vpl);
static void vacuum_page(Page page, VPageDescr vpd); static void vacuum_page(Page page, VPageDescr vpd);
static void vacuum_index(VPageList vpl, Relation indrel, int num_tuples, int keep_tuples); static void vacuum_index(VPageList vpl, Relation indrel, int num_tuples, int keep_tuples);
static void scan_index(Relation indrel, int num_tuples); static void scan_index(Relation indrel, int num_tuples);
static void attr_stats(Relation onerel, VRelStats *vacrelstats, HeapTuple tuple); static void attr_stats(Relation onerel, int attr_cnt, VacAttrStats *vacattrstats, HeapTuple tuple);
static void bucketcpy(Form_pg_attribute attr, Datum value, Datum *bucket, int *bucket_len); static void bucketcpy(Form_pg_attribute attr, Datum value, Datum *bucket, int *bucket_len);
static void update_stats(Oid relid, int num_pages, int num_tuples, bool hasindex, VRelStats *vacrelstats); static void update_relstats(Oid relid, int num_pages, int num_tuples, bool hasindex, VRelStats *vacrelstats);
static void update_attstats(Oid relid, int natts, VacAttrStats *vacattrstats);
static void del_stats(Oid relid, int attcnt, int *attnums); static void del_stats(Oid relid, int attcnt, int *attnums);
static VPageDescr tid_reaped(ItemPointer itemptr, VPageList vpl); static VPageDescr tid_reaped(ItemPointer itemptr, VPageList vpl);
static void reap_page(VPageList vpl, VPageDescr vpc); static void reap_page(VPageList vpl, VPageDescr vpc);
@ -100,63 +102,7 @@ static int vac_cmp_offno(const void *left, const void *right);
static int vac_cmp_vtlinks(const void *left, const void *right); static int vac_cmp_vtlinks(const void *left, const void *right);
static bool enough_space(VPageDescr vpd, Size len); static bool enough_space(VPageDescr vpd, Size len);
static char *show_rusage(struct rusage * ru0); static char *show_rusage(struct rusage * ru0);
/* CommonSpecialPortal function at the bottom */
/*
* This routines handle a special cross-transaction portal.
* However it is automatically closed in case of abort.
*/
void
CommonSpecialPortalOpen(void)
{
char *pname;
if (CommonSpecialPortalInUse)
elog(ERROR, "CommonSpecialPortal is in use");
/*
* Create a portal for safe memory across transactions. We need to
* palloc the name space for it because our hash function expects the
* name to be on a longword boundary. CreatePortal copies the name to
* safe storage for us.
*/
pname = pstrdup(VACPNAME);
vac_portal = CreatePortal(pname);
pfree(pname);
/*
* Set flag to indicate that vac_portal must be removed after an error.
* This global variable is checked in the transaction manager on xact
* abort, and the routine CommonSpecialPortalClose() is called if
* necessary.
*/
CommonSpecialPortalInUse = true;
}
void
CommonSpecialPortalClose(void)
{
/* Clear flag first, to avoid recursion if PortalDrop elog's */
CommonSpecialPortalInUse = false;
/*
* Release our portal for cross-transaction memory.
*/
PortalDrop(&vac_portal);
}
PortalVariableMemory
CommonSpecialPortalGetMemory(void)
{
return PortalGetVariableMemory(vac_portal);
}
bool
CommonSpecialPortalIsOpen(void)
{
return CommonSpecialPortalInUse;
}
void void
vacuum(char *vacrel, bool verbose, bool analyze, List *va_spec) vacuum(char *vacrel, bool verbose, bool analyze, List *va_spec)
@ -299,6 +245,11 @@ vac_vacuum(NameData *VacRelP, bool analyze, List *va_cols)
/* vacuum each heap relation */ /* vacuum each heap relation */
for (cur = vrl; cur != (VRelList) NULL; cur = cur->vrl_next) for (cur = vrl; cur != (VRelList) NULL; cur = cur->vrl_next)
vacuum_rel(cur->vrl_relid, analyze, va_cols); vacuum_rel(cur->vrl_relid, analyze, va_cols);
/* analyze separately so locking is minimized */
if (analyze)
for (cur = vrl; cur != (VRelList) NULL; cur = cur->vrl_next)
analyze_rel(cur->vrl_relid, va_cols);
} }
static VRelList static VRelList
@ -410,8 +361,7 @@ getrels(NameData *VacRelP)
static void static void
vacuum_rel(Oid relid, bool analyze, List *va_cols) vacuum_rel(Oid relid, bool analyze, List *va_cols)
{ {
HeapTuple tuple, HeapTuple tuple;
typetuple;
Relation onerel; Relation onerel;
VPageListData vacuum_pages; /* List of pages to vacuum and/or clean VPageListData vacuum_pages; /* List of pages to vacuum and/or clean
* indices */ * indices */
@ -474,125 +424,6 @@ vacuum_rel(Oid relid, bool analyze, List *va_cols)
vacrelstats->num_pages = vacrelstats->num_tuples = 0; vacrelstats->num_pages = vacrelstats->num_tuples = 0;
vacrelstats->hasindex = false; vacrelstats->hasindex = false;
/*
* we can VACUUM ANALYZE any table except pg_statistic; see
* update_stats
*/
if (analyze &&
strcmp(RelationGetRelationName(onerel), StatisticRelationName) != 0)
{
int attr_cnt,
*attnums = NULL;
Form_pg_attribute *attr;
attr_cnt = onerel->rd_att->natts;
attr = onerel->rd_att->attrs;
if (va_cols != NIL)
{
int tcnt = 0;
List *le;
if (length(va_cols) > attr_cnt)
elog(ERROR, "vacuum: too many attributes specified for relation %s",
RelationGetRelationName(onerel));
attnums = (int *) palloc(attr_cnt * sizeof(int));
foreach(le, va_cols)
{
char *col = (char *) lfirst(le);
for (i = 0; i < attr_cnt; i++)
{
if (namestrcmp(&(attr[i]->attname), col) == 0)
break;
}
if (i < attr_cnt) /* found */
attnums[tcnt++] = i;
else
{
elog(ERROR, "vacuum: there is no attribute %s in %s",
col, RelationGetRelationName(onerel));
}
}
attr_cnt = tcnt;
}
vacrelstats->vacattrstats = (VacAttrStats *) palloc(attr_cnt * sizeof(VacAttrStats));
for (i = 0; i < attr_cnt; i++)
{
Operator func_operator;
Form_pg_operator pgopform;
VacAttrStats *stats;
stats = &vacrelstats->vacattrstats[i];
stats->attr = palloc(ATTRIBUTE_TUPLE_SIZE);
memmove(stats->attr, attr[((attnums) ? attnums[i] : i)], ATTRIBUTE_TUPLE_SIZE);
stats->best = stats->guess1 = stats->guess2 = 0;
stats->max = stats->min = 0;
stats->best_len = stats->guess1_len = stats->guess2_len = 0;
stats->max_len = stats->min_len = 0;
stats->initialized = false;
stats->best_cnt = stats->guess1_cnt = stats->guess1_hits = stats->guess2_hits = 0;
stats->max_cnt = stats->min_cnt = stats->null_cnt = stats->nonnull_cnt = 0;
func_operator = oper("=", stats->attr->atttypid, stats->attr->atttypid, true);
if (func_operator != NULL)
{
pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
fmgr_info(pgopform->oprcode, &(stats->f_cmpeq));
}
else
stats->f_cmpeq.fn_addr = NULL;
func_operator = oper("<", stats->attr->atttypid, stats->attr->atttypid, true);
if (func_operator != NULL)
{
pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
fmgr_info(pgopform->oprcode, &(stats->f_cmplt));
stats->op_cmplt = oprid(func_operator);
}
else
{
stats->f_cmplt.fn_addr = NULL;
stats->op_cmplt = InvalidOid;
}
func_operator = oper(">", stats->attr->atttypid, stats->attr->atttypid, true);
if (func_operator != NULL)
{
pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
fmgr_info(pgopform->oprcode, &(stats->f_cmpgt));
}
else
stats->f_cmpgt.fn_addr = NULL;
typetuple = SearchSysCacheTuple(TYPEOID,
ObjectIdGetDatum(stats->attr->atttypid),
0, 0, 0);
if (HeapTupleIsValid(typetuple))
{
stats->outfunc = ((Form_pg_type) GETSTRUCT(typetuple))->typoutput;
stats->typelem = ((Form_pg_type) GETSTRUCT(typetuple))->typelem;
}
else
{
stats->outfunc = InvalidOid;
stats->typelem = InvalidOid;
}
}
vacrelstats->va_natts = attr_cnt;
/* delete existing pg_statistic rows for relation */
del_stats(relid, ((attnums) ? attr_cnt : 0), attnums);
if (attnums)
pfree(attnums);
}
else
{
vacrelstats->va_natts = 0;
vacrelstats->vacattrstats = (VacAttrStats *) NULL;
}
GetXmaxRecent(&XmaxRecent); GetXmaxRecent(&XmaxRecent);
/* scan it */ /* scan it */
@ -631,7 +462,7 @@ vacuum_rel(Oid relid, bool analyze, List *va_cols)
vacuum_index(&vacuum_pages, Irel[i], vacrelstats->num_tuples, 0); vacuum_index(&vacuum_pages, Irel[i], vacrelstats->num_tuples, 0);
} }
else else
/* just scan indices to update statistic */ /* just scan indices to update statistic */
{ {
for (i = 0; i < nindices; i++) for (i = 0; i < nindices; i++)
scan_index(Irel[i], vacrelstats->num_tuples); scan_index(Irel[i], vacrelstats->num_tuples);
@ -662,17 +493,197 @@ vacuum_rel(Oid relid, bool analyze, List *va_cols)
pfree(fraged_pages.vpl_pagedesc); pfree(fraged_pages.vpl_pagedesc);
} }
/* update statistics in pg_class */
update_stats(vacrelstats->relid, vacrelstats->num_pages,
vacrelstats->num_tuples, vacrelstats->hasindex, vacrelstats);
/* all done with this class, but hold lock until commit */ /* all done with this class, but hold lock until commit */
heap_close(onerel, NoLock); heap_close(onerel, NoLock);
/* update statistics in pg_class */
update_relstats(vacrelstats->relid, vacrelstats->num_pages,
vacrelstats->num_tuples, vacrelstats->hasindex, vacrelstats);
/* next command frees attribute stats */ /* next command frees attribute stats */
CommitTransactionCommand(); CommitTransactionCommand();
} }
/*
* analyze_rel() -- analyze relation
*/
static void
analyze_rel(Oid relid, List *va_cols)
{
HeapTuple tuple,
typetuple;
Relation onerel;
int32 i;
int attr_cnt,
*attnums = NULL;
Form_pg_attribute *attr;
VacAttrStats *vacattrstats;
HeapScanDesc scan;
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);
/*
* We can VACUUM ANALYZE any table except pg_statistic.
* see update_relstats
*/
if (!HeapTupleIsValid(tuple) ||
strcmp(NameStr(((Form_pg_class) GETSTRUCT(tuple))->relname),
StatisticRelationName) == 0)
{
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, AccessShareLock);
#ifndef NO_SECURITY
if (!pg_ownercheck(GetPgUserName(), RelationGetRelationName(onerel),
RELNAME))
{
/* we already did an elog during vacuum
elog(NOTICE, "Skipping \"%s\" --- only table owner can VACUUM it",
RelationGetRelationName(onerel));
*/
heap_close(onerel, AccessExclusiveLock);
CommitTransactionCommand();
return;
}
#endif
attr_cnt = onerel->rd_att->natts;
attr = onerel->rd_att->attrs;
if (va_cols != NIL)
{
int tcnt = 0;
List *le;
if (length(va_cols) > attr_cnt)
elog(ERROR, "vacuum: too many attributes specified for relation %s",
RelationGetRelationName(onerel));
attnums = (int *) palloc(attr_cnt * sizeof(int));
foreach(le, va_cols)
{
char *col = (char *) lfirst(le);
for (i = 0; i < attr_cnt; i++)
{
if (namestrcmp(&(attr[i]->attname), col) == 0)
break;
}
if (i < attr_cnt) /* found */
attnums[tcnt++] = i;
else
{
elog(ERROR, "vacuum: there is no attribute %s in %s",
col, RelationGetRelationName(onerel));
}
}
attr_cnt = tcnt;
}
vacattrstats = (VacAttrStats *) palloc(attr_cnt * sizeof(VacAttrStats));
for (i = 0; i < attr_cnt; i++)
{
Operator func_operator;
Form_pg_operator pgopform;
VacAttrStats *stats;
stats = &vacattrstats[i];
stats->attr = palloc(ATTRIBUTE_TUPLE_SIZE);
memmove(stats->attr, attr[((attnums) ? attnums[i] : i)], ATTRIBUTE_TUPLE_SIZE);
stats->best = stats->guess1 = stats->guess2 = 0;
stats->max = stats->min = 0;
stats->best_len = stats->guess1_len = stats->guess2_len = 0;
stats->max_len = stats->min_len = 0;
stats->initialized = false;
stats->best_cnt = stats->guess1_cnt = stats->guess1_hits = stats->guess2_hits = 0;
stats->max_cnt = stats->min_cnt = stats->null_cnt = stats->nonnull_cnt = 0;
func_operator = oper("=", stats->attr->atttypid, stats->attr->atttypid, true);
if (func_operator != NULL)
{
pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
fmgr_info(pgopform->oprcode, &(stats->f_cmpeq));
}
else
stats->f_cmpeq.fn_addr = NULL;
func_operator = oper("<", stats->attr->atttypid, stats->attr->atttypid, true);
if (func_operator != NULL)
{
pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
fmgr_info(pgopform->oprcode, &(stats->f_cmplt));
stats->op_cmplt = oprid(func_operator);
}
else
{
stats->f_cmplt.fn_addr = NULL;
stats->op_cmplt = InvalidOid;
}
func_operator = oper(">", stats->attr->atttypid, stats->attr->atttypid, true);
if (func_operator != NULL)
{
pgopform = (Form_pg_operator) GETSTRUCT(func_operator);
fmgr_info(pgopform->oprcode, &(stats->f_cmpgt));
}
else
stats->f_cmpgt.fn_addr = NULL;
typetuple = SearchSysCacheTuple(TYPEOID,
ObjectIdGetDatum(stats->attr->atttypid),
0, 0, 0);
if (HeapTupleIsValid(typetuple))
{
stats->outfunc = ((Form_pg_type) GETSTRUCT(typetuple))->typoutput;
stats->typelem = ((Form_pg_type) GETSTRUCT(typetuple))->typelem;
}
else
{
stats->outfunc = InvalidOid;
stats->typelem = InvalidOid;
}
}
/* delete existing pg_statistic rows for relation */
del_stats(relid, ((attnums) ? attr_cnt : 0), attnums);
scan = heap_beginscan(onerel, false, SnapshotNow, 0, NULL);
while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
attr_stats(onerel, attr_cnt, vacattrstats, tuple);
heap_endscan(scan);
heap_close(onerel, AccessShareLock);
/* update statistics in pg_class */
update_attstats(relid, attr_cnt, vacattrstats);
CommitTransactionCommand();
}
/* /*
* scan_heap() -- scan an open heap relation * scan_heap() -- scan an open heap relation
* *
@ -979,7 +990,6 @@ scan_heap(VRelStats *vacrelstats, Relation onerel,
min_tlen = tuple.t_len; min_tlen = tuple.t_len;
if (tuple.t_len > max_tlen) if (tuple.t_len > max_tlen)
max_tlen = tuple.t_len; max_tlen = tuple.t_len;
attr_stats(onerel, vacrelstats, &tuple);
} }
} }
@ -2106,7 +2116,7 @@ scan_index(Relation indrel, int num_tuples)
/* now update statistics in pg_class */ /* now update statistics in pg_class */
nipages = RelationGetNumberOfBlocks(indrel); nipages = RelationGetNumberOfBlocks(indrel);
update_stats(RelationGetRelid(indrel), nipages, nitups, false, NULL); update_relstats(RelationGetRelid(indrel), nipages, nitups, false, NULL);
elog(MESSAGE_LEVEL, "Index %s: Pages %u; Tuples %u. %s", elog(MESSAGE_LEVEL, "Index %s: Pages %u; Tuples %u. %s",
RelationGetRelationName(indrel), nipages, nitups, RelationGetRelationName(indrel), nipages, nitups,
@ -2183,7 +2193,7 @@ vacuum_index(VPageList vpl, Relation indrel, int num_tuples, int keep_tuples)
/* now update statistics in pg_class */ /* now update statistics in pg_class */
num_pages = RelationGetNumberOfBlocks(indrel); num_pages = RelationGetNumberOfBlocks(indrel);
update_stats(RelationGetRelid(indrel), num_pages, num_index_tuples, false, NULL); update_relstats(RelationGetRelid(indrel), num_pages, num_index_tuples, false, NULL);
elog(MESSAGE_LEVEL, "Index %s: Pages %u; Tuples %u: Deleted %u. %s", elog(MESSAGE_LEVEL, "Index %s: Pages %u; Tuples %u: Deleted %u. %s",
RelationGetRelationName(indrel), num_pages, RelationGetRelationName(indrel), num_pages,
@ -2263,11 +2273,9 @@ tid_reaped(ItemPointer itemptr, VPageList vpl)
* *
*/ */
static void static void
attr_stats(Relation onerel, VRelStats *vacrelstats, HeapTuple tuple) attr_stats(Relation onerel, int attr_cnt, VacAttrStats *vacattrstats, HeapTuple tuple)
{ {
int i, int i;
attr_cnt = vacrelstats->va_natts;
VacAttrStats *vacattrstats = vacrelstats->vacattrstats;
TupleDesc tupDesc = onerel->rd_att; TupleDesc tupDesc = onerel->rd_att;
Datum value; Datum value;
bool isnull; bool isnull;
@ -2387,7 +2395,7 @@ bucketcpy(Form_pg_attribute attr, Datum value, Datum *bucket, int *bucket_len)
} }
/* /*
* update_stats() -- update statistics for one relation * update_relstats() -- update statistics for one relation
* *
* Statistics are stored in several places: the pg_class row for the * Statistics are stored in several places: the pg_class row for the
* relation has stats about the whole relation, the pg_attribute rows * relation has stats about the whole relation, the pg_attribute rows
@ -2408,29 +2416,15 @@ bucketcpy(Form_pg_attribute attr, Datum value, Datum *bucket, int *bucket_len)
* Updating pg_class's own statistics would be especially tricky. * Updating pg_class's own statistics would be especially tricky.
* Of course, this only works for fixed-size never-null columns, but * Of course, this only works for fixed-size never-null columns, but
* these are. * these are.
*
* Updates of pg_attribute statistics are handled in the same way
* for the same reasons.
*
* To keep things simple, we punt for pg_statistic, and don't try
* to compute or store rows for pg_statistic itself in pg_statistic.
* This could possibly be made to work, but it's not worth the trouble.
*/ */
static void static void
update_stats(Oid relid, int num_pages, int num_tuples, bool hasindex, update_relstats(Oid relid, int num_pages, int num_tuples, bool hasindex,
VRelStats *vacrelstats) VRelStats *vacrelstats)
{ {
Relation rd, Relation rd;
ad,
sd;
HeapScanDesc scan;
HeapTupleData rtup; HeapTupleData rtup;
HeapTuple ctup, HeapTuple ctup;
atup,
stup;
Form_pg_class pgcform; Form_pg_class pgcform;
ScanKeyData askey;
Form_pg_attribute attp;
Buffer buffer; Buffer buffer;
/* /*
@ -2461,202 +2455,217 @@ update_stats(Oid relid, int num_pages, int num_tuples, bool hasindex,
WriteBuffer(buffer); WriteBuffer(buffer);
heap_close(rd, RowExclusiveLock); heap_close(rd, RowExclusiveLock);
}
if (vacrelstats != NULL && vacrelstats->va_natts > 0) /*
* update_attstats() -- update attribute statistics for one relation
*
* Updates of pg_attribute statistics are handled by over-write.
* for reasons described above.
*
* To keep things simple, we punt for pg_statistic, and don't try
* to compute or store rows for pg_statistic itself in pg_statistic.
* This could possibly be made to work, but it's not worth the trouble.
*/
static void
update_attstats(Oid relid, int natts, VacAttrStats *vacattrstats)
{
Relation ad,
sd;
HeapScanDesc scan;
HeapTuple atup,
stup;
ScanKeyData askey;
Form_pg_attribute attp;
ad = heap_openr(AttributeRelationName, RowExclusiveLock);
sd = heap_openr(StatisticRelationName, RowExclusiveLock);
/* Find pg_attribute rows for this relation */
ScanKeyEntryInitialize(&askey, 0, Anum_pg_attribute_attrelid,
F_INT4EQ, relid);
scan = heap_beginscan(ad, false, SnapshotNow, 1, &askey);
while (HeapTupleIsValid(atup = heap_getnext(scan, 0)))
{ {
VacAttrStats *vacattrstats = vacrelstats->vacattrstats; int i;
int natts = vacrelstats->va_natts; VacAttrStats *stats;
ad = heap_openr(AttributeRelationName, RowExclusiveLock); attp = (Form_pg_attribute) GETSTRUCT(atup);
sd = heap_openr(StatisticRelationName, RowExclusiveLock); if (attp->attnum <= 0) /* skip system attributes for now */
continue;
/* Find pg_attribute rows for this relation */ for (i = 0; i < natts; i++)
ScanKeyEntryInitialize(&askey, 0, Anum_pg_attribute_attrelid,
F_INT4EQ, relid);
scan = heap_beginscan(ad, false, SnapshotNow, 1, &askey);
while (HeapTupleIsValid(atup = heap_getnext(scan, 0)))
{ {
int i; if (attp->attnum == vacattrstats[i].attr->attnum)
VacAttrStats *stats; break;
}
if (i >= natts)
continue; /* skip attr if no stats collected */
stats = &(vacattrstats[i]);
attp = (Form_pg_attribute) GETSTRUCT(atup); if (VacAttrStatsEqValid(stats))
if (attp->attnum <= 0) /* skip system attributes for now */ {
continue; float32data selratio; /* average ratio of rows selected
* for a random constant */
for (i = 0; i < natts; i++) /* Compute disbursion */
if (stats->nonnull_cnt == 0 && stats->null_cnt == 0)
{ {
if (attp->attnum == vacattrstats[i].attr->attnum)
break; /*
* empty relation, so put a dummy value in
* attdisbursion
*/
selratio = 0;
} }
if (i >= natts) else if (stats->null_cnt <= 1 && stats->best_cnt == 1)
continue; /* skip attr if no stats collected */
stats = &(vacattrstats[i]);
if (VacAttrStatsEqValid(stats))
{ {
float32data selratio; /* average ratio of rows selected /*
* for a random constant */ * looks like we have a unique-key attribute --- flag
* this with special -1.0 flag value.
/* Compute disbursion */ *
if (stats->nonnull_cnt == 0 && stats->null_cnt == 0) * The correct disbursion is 1.0/numberOfRows, but since
* the relation row count can get updated without
* recomputing disbursion, we want to store a
* "symbolic" value and figure 1.0/numberOfRows on the
* fly.
*/
selratio = -1;
}
else
{
if (VacAttrStatsLtGtValid(stats) &&
stats->min_cnt + stats->max_cnt == stats->nonnull_cnt)
{ {
/* /*
* empty relation, so put a dummy value in * exact result when there are just 1 or 2
* attdisbursion * values...
*/ */
selratio = 0; double min_cnt_d = stats->min_cnt,
} max_cnt_d = stats->max_cnt,
else if (stats->null_cnt <= 1 && stats->best_cnt == 1) null_cnt_d = stats->null_cnt;
{ double total = ((double) stats->nonnull_cnt) + null_cnt_d;
/* selratio = (min_cnt_d * min_cnt_d + max_cnt_d * max_cnt_d + null_cnt_d * null_cnt_d) / (total * total);
* looks like we have a unique-key attribute --- flag
* this with special -1.0 flag value.
*
* The correct disbursion is 1.0/numberOfRows, but since
* the relation row count can get updated without
* recomputing disbursion, we want to store a
* "symbolic" value and figure 1.0/numberOfRows on the
* fly.
*/
selratio = -1;
} }
else else
{ {
if (VacAttrStatsLtGtValid(stats) && double most = (double) (stats->best_cnt > stats->null_cnt ? stats->best_cnt : stats->null_cnt);
stats->min_cnt + stats->max_cnt == stats->nonnull_cnt) double total = ((double) stats->nonnull_cnt) + ((double) stats->null_cnt);
{
/* /*
* exact result when there are just 1 or 2 * we assume count of other values are 20% of best
* values... * count in table
*/ */
double min_cnt_d = stats->min_cnt, selratio = (most * most + 0.20 * most * (total - most)) / (total * total);
max_cnt_d = stats->max_cnt,
null_cnt_d = stats->null_cnt;
double total = ((double) stats->nonnull_cnt) + null_cnt_d;
selratio = (min_cnt_d * min_cnt_d + max_cnt_d * max_cnt_d + null_cnt_d * null_cnt_d) / (total * total);
}
else
{
double most = (double) (stats->best_cnt > stats->null_cnt ? stats->best_cnt : stats->null_cnt);
double total = ((double) stats->nonnull_cnt) + ((double) stats->null_cnt);
/*
* we assume count of other values are 20% of best
* count in table
*/
selratio = (most * most + 0.20 * most * (total - most)) / (total * total);
}
/* Make sure calculated values are in-range */
if (selratio < 0.0)
selratio = 0.0;
else if (selratio > 1.0)
selratio = 1.0;
} }
/* Make sure calculated values are in-range */
if (selratio < 0.0)
selratio = 0.0;
else if (selratio > 1.0)
selratio = 1.0;
}
/* overwrite the existing statistics in the tuple */ /* overwrite the existing statistics in the tuple */
attp->attdisbursion = selratio; attp->attdisbursion = selratio;
/* invalidate the tuple in the cache and write the buffer */ /* invalidate the tuple in the cache and write the buffer */
RelationInvalidateHeapTuple(ad, atup); RelationInvalidateHeapTuple(ad, atup);
WriteNoReleaseBuffer(scan->rs_cbuf); WriteNoReleaseBuffer(scan->rs_cbuf);
/* /*
* Create pg_statistic tuples for the relation, if we have * Create pg_statistic tuples for the relation, if we have
* gathered the right data. del_stats() previously * gathered the right data. del_stats() previously
* deleted all the pg_statistic tuples for the rel, so we * deleted all the pg_statistic tuples for the rel, so we
* just have to insert new ones here. * just have to insert new ones here.
* *
* Note vacuum_rel() has seen to it that we won't come here * Note vacuum_rel() has seen to it that we won't come here
* when vacuuming pg_statistic itself. * when vacuuming pg_statistic itself.
*/
if (VacAttrStatsLtGtValid(stats) && stats->initialized)
{
float32data nullratio;
float32data bestratio;
FmgrInfo out_function;
char *out_string;
double best_cnt_d = stats->best_cnt,
null_cnt_d = stats->null_cnt,
nonnull_cnt_d = stats->nonnull_cnt; /* prevent overflow */
Datum values[Natts_pg_statistic];
char nulls[Natts_pg_statistic];
nullratio = null_cnt_d / (nonnull_cnt_d + null_cnt_d);
bestratio = best_cnt_d / (nonnull_cnt_d + null_cnt_d);
fmgr_info(stats->outfunc, &out_function);
for (i = 0; i < Natts_pg_statistic; ++i)
nulls[i] = ' ';
/* ----------------
* initialize values[]
* ----------------
*/ */
if (VacAttrStatsLtGtValid(stats) && stats->initialized) i = 0;
values[i++] = (Datum) relid; /* starelid */
values[i++] = (Datum) attp->attnum; /* staattnum */
values[i++] = (Datum) stats->op_cmplt; /* staop */
/* hack: this code knows float4 is pass-by-ref */
values[i++] = PointerGetDatum(&nullratio); /* stanullfrac */
values[i++] = PointerGetDatum(&bestratio); /* stacommonfrac */
out_string = (*fmgr_faddr(&out_function)) (stats->best, stats->typelem, stats->attr->atttypmod);
values[i++] = PointerGetDatum(textin(out_string)); /* stacommonval */
pfree(out_string);
out_string = (*fmgr_faddr(&out_function)) (stats->min, stats->typelem, stats->attr->atttypmod);
values[i++] = PointerGetDatum(textin(out_string)); /* staloval */
pfree(out_string);
out_string = (char *) (*fmgr_faddr(&out_function)) (stats->max, stats->typelem, stats->attr->atttypmod);
values[i++] = PointerGetDatum(textin(out_string)); /* stahival */
pfree(out_string);
stup = heap_formtuple(sd->rd_att, values, nulls);
/* ----------------
* Watch out for oversize tuple, which can happen if
* all three of the saved data values are long.
* Our fallback strategy is just to not store the
* pg_statistic tuple at all in that case. (We could
* replace the values by NULLs and still store the
* numeric stats, but presently selfuncs.c couldn't
* do anything useful with that case anyway.)
*
* We could reduce the probability of overflow, but not
* prevent it, by storing the data values as compressed
* text; is that worth doing? The problem should go
* away whenever long tuples get implemented...
* ----------------
*/
if (MAXALIGN(stup->t_len) <= MaxTupleSize)
{ {
float32data nullratio; /* OK, store tuple and update indexes too */
float32data bestratio; Relation irelations[Num_pg_statistic_indices];
FmgrInfo out_function;
char *out_string;
double best_cnt_d = stats->best_cnt,
null_cnt_d = stats->null_cnt,
nonnull_cnt_d = stats->nonnull_cnt; /* prevent overflow */
Datum values[Natts_pg_statistic];
char nulls[Natts_pg_statistic];
nullratio = null_cnt_d / (nonnull_cnt_d + null_cnt_d); heap_insert(sd, stup);
bestratio = best_cnt_d / (nonnull_cnt_d + null_cnt_d); CatalogOpenIndices(Num_pg_statistic_indices, Name_pg_statistic_indices, irelations);
CatalogIndexInsert(irelations, Num_pg_statistic_indices, sd, stup);
fmgr_info(stats->outfunc, &out_function); CatalogCloseIndices(Num_pg_statistic_indices, irelations);
for (i = 0; i < Natts_pg_statistic; ++i)
nulls[i] = ' ';
/* ----------------
* initialize values[]
* ----------------
*/
i = 0;
values[i++] = (Datum) relid; /* starelid */
values[i++] = (Datum) attp->attnum; /* staattnum */
values[i++] = (Datum) stats->op_cmplt; /* staop */
/* hack: this code knows float4 is pass-by-ref */
values[i++] = PointerGetDatum(&nullratio); /* stanullfrac */
values[i++] = PointerGetDatum(&bestratio); /* stacommonfrac */
out_string = (*fmgr_faddr(&out_function)) (stats->best, stats->typelem, stats->attr->atttypmod);
values[i++] = PointerGetDatum(textin(out_string)); /* stacommonval */
pfree(out_string);
out_string = (*fmgr_faddr(&out_function)) (stats->min, stats->typelem, stats->attr->atttypmod);
values[i++] = PointerGetDatum(textin(out_string)); /* staloval */
pfree(out_string);
out_string = (char *) (*fmgr_faddr(&out_function)) (stats->max, stats->typelem, stats->attr->atttypmod);
values[i++] = PointerGetDatum(textin(out_string)); /* stahival */
pfree(out_string);
stup = heap_formtuple(sd->rd_att, values, nulls);
/* ----------------
* Watch out for oversize tuple, which can happen if
* all three of the saved data values are long.
* Our fallback strategy is just to not store the
* pg_statistic tuple at all in that case. (We could
* replace the values by NULLs and still store the
* numeric stats, but presently selfuncs.c couldn't
* do anything useful with that case anyway.)
*
* We could reduce the probability of overflow, but not
* prevent it, by storing the data values as compressed
* text; is that worth doing? The problem should go
* away whenever long tuples get implemented...
* ----------------
*/
if (MAXALIGN(stup->t_len) <= MaxTupleSize)
{
/* OK, store tuple and update indexes too */
Relation irelations[Num_pg_statistic_indices];
heap_insert(sd, stup);
CatalogOpenIndices(Num_pg_statistic_indices, Name_pg_statistic_indices, irelations);
CatalogIndexInsert(irelations, Num_pg_statistic_indices, sd, stup);
CatalogCloseIndices(Num_pg_statistic_indices, irelations);
}
/* release allocated space */
pfree(DatumGetPointer(values[Anum_pg_statistic_stacommonval - 1]));
pfree(DatumGetPointer(values[Anum_pg_statistic_staloval - 1]));
pfree(DatumGetPointer(values[Anum_pg_statistic_stahival - 1]));
heap_freetuple(stup);
} }
/* release allocated space */
pfree(DatumGetPointer(values[Anum_pg_statistic_stacommonval - 1]));
pfree(DatumGetPointer(values[Anum_pg_statistic_staloval - 1]));
pfree(DatumGetPointer(values[Anum_pg_statistic_stahival - 1]));
heap_freetuple(stup);
} }
} }
heap_endscan(scan);
/* close rels, but hold locks till upcoming commit */
heap_close(ad, NoLock);
heap_close(sd, NoLock);
} }
heap_endscan(scan);
/* close rels, but hold locks till upcoming commit */
heap_close(ad, NoLock);
heap_close(sd, NoLock);
} }
/* /*
@ -2867,6 +2876,62 @@ vac_cmp_vtlinks(const void *left, const void *right)
} }
/*
* This routines handle a special cross-transaction portal.
* However it is automatically closed in case of abort.
*/
void
CommonSpecialPortalOpen(void)
{
char *pname;
if (CommonSpecialPortalInUse)
elog(ERROR, "CommonSpecialPortal is in use");
/*
* Create a portal for safe memory across transactions. We need to
* palloc the name space for it because our hash function expects the
* name to be on a longword boundary. CreatePortal copies the name to
* safe storage for us.
*/
pname = pstrdup(VACPNAME);
vac_portal = CreatePortal(pname);
pfree(pname);
/*
* Set flag to indicate that vac_portal must be removed after an error.
* This global variable is checked in the transaction manager on xact
* abort, and the routine CommonSpecialPortalClose() is called if
* necessary.
*/
CommonSpecialPortalInUse = true;
}
void
CommonSpecialPortalClose(void)
{
/* Clear flag first, to avoid recursion if PortalDrop elog's */
CommonSpecialPortalInUse = false;
/*
* Release our portal for cross-transaction memory.
*/
PortalDrop(&vac_portal);
}
PortalVariableMemory
CommonSpecialPortalGetMemory(void)
{
return PortalGetVariableMemory(vac_portal);
}
bool
CommonSpecialPortalIsOpen(void)
{
return CommonSpecialPortalInUse;
}
static void static void
get_indices(Oid relid, int *nindices, Relation **Irel) get_indices(Oid relid, int *nindices, Relation **Irel)
{ {

4
src/include/commands/vacuum.h
View File

@ -7,7 +7,7 @@
* Portions Copyright (c) 1996-2000, PostgreSQL, Inc * Portions Copyright (c) 1996-2000, PostgreSQL, Inc
* Portions Copyright (c) 1994, Regents of the University of California * Portions Copyright (c) 1994, Regents of the University of California
* *
* $Id: vacuum.h,v 1.27 2000/04/12 17:16:32 momjian Exp $ * $Id: vacuum.h,v 1.28 2000/05/29 15:44:55 momjian Exp $
* *
*------------------------------------------------------------------------- *-------------------------------------------------------------------------
*/ */
@ -125,8 +125,6 @@ typedef struct VRelStats
Size min_tlen; Size min_tlen;
Size max_tlen; Size max_tlen;
bool hasindex; bool hasindex;
int va_natts; /* number of attrs being analyzed */
VacAttrStats *vacattrstats;
int num_vtlinks; int num_vtlinks;
VTupleLink vtlinks; VTupleLink vtlinks;
} VRelStats; } VRelStats;