*
*
* IDENTIFICATION
- * $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.158 2000/05/29 17:11:58 momjian Exp $
+ * $Header: /cvsroot/pgsql/src/backend/commands/vacuum.c,v 1.159 2000/05/29 17:40:43 momjian Exp $
*
*-------------------------------------------------------------------------
#include "access/genam.h"
#include "access/heapam.h"
-#include "access/xact.h"
#include "catalog/catalog.h"
#include "catalog/catname.h"
#include "catalog/index.h"
-#include "catalog/indexing.h"
-#include "catalog/pg_operator.h"
-#include "catalog/pg_statistic.h"
-#include "catalog/pg_type.h"
#include "commands/vacuum.h"
#include "miscadmin.h"
-#include "parser/parse_oper.h"
#include "storage/sinval.h"
#include "storage/smgr.h"
#include "tcop/tcopprot.h"
static TransactionId XmaxRecent;
-#define swapLong(a,b) {long tmp; tmp=a; a=b; b=tmp;}
-#define swapInt(a,b) {int tmp; tmp=a; a=b; b=tmp;}
-#define swapDatum(a,b) {Datum tmp; tmp=a; a=b; b=tmp;}
-#define VacAttrStatsEqValid(stats) ( stats->f_cmpeq.fn_addr != NULL )
-#define VacAttrStatsLtGtValid(stats) ( stats->f_cmplt.fn_addr != NULL && \
- stats->f_cmpgt.fn_addr != NULL && \
- RegProcedureIsValid(stats->outfunc) )
-
-
/* 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);
-static void analyze_rel(Oid relid, List *anal_cols2);
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 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 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 VacPage tid_reaped(ItemPointer itemptr, VacPageList vacpagelist);
static void reap_page(VacPageList vacpagelist, VacPage vacpage);
static void vpage_insert(VacPageList vacpagelist, VacPage vpnew);
vacuum_rel(cur->vrl_relid, analyze);
/* analyze separately so locking is minimized */
if (analyze)
- analyze_rel(cur->vrl_relid, anal_cols2);
+ analyze_rel(cur->vrl_relid, anal_cols2, MESSAGE_LEVEL);
}
}
CommitTransactionCommand();
}
-/*
- * analyze_rel() -- analyze relation
- */
-static void
-analyze_rel(Oid relid, List *anal_cols2)
-{
- 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;
- }
-
- 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
-
- elog(MESSAGE_LEVEL, "Analyzing...");
-
- attr_cnt = onerel->rd_att->natts;
- attr = onerel->rd_att->attrs;
-
- if (anal_cols2 != NIL)
- {
- int tcnt = 0;
- List *le;
-
- if (length(anal_cols2) > attr_cnt)
- elog(ERROR, "vacuum: too many attributes specified for relation %s",
- RelationGetRelationName(onerel));
- attnums = (int *) palloc(attr_cnt * sizeof(int));
- foreach(le, anal_cols2)
- {
- 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
*
}
-/*
- * attr_stats() -- compute column statistics used by the optimzer
- *
- * We compute the column min, max, null and non-null counts.
- * Plus we attempt to find the count of the value that occurs most
- * frequently in each column. These figures are used to compute
- * the selectivity of the column.
- *
- * We use a three-bucked cache to get the most frequent item.
- * The 'guess' buckets count hits. A cache miss causes guess1
- * to get the most hit 'guess' item in the most recent cycle, and
- * the new item goes into guess2. Whenever the total count of hits
- * of a 'guess' entry is larger than 'best', 'guess' becomes 'best'.
- *
- * This method works perfectly for columns with unique values, and columns
- * with only two unique values, plus nulls.
- *
- * It becomes less perfect as the number of unique values increases and
- * their distribution in the table becomes more random.
- *
- */
-static void
-attr_stats(Relation onerel, int attr_cnt, VacAttrStats *vacattrstats, HeapTuple tuple)
-{
- int i;
- TupleDesc tupDesc = onerel->rd_att;
- Datum value;
- bool isnull;
-
- for (i = 0; i < attr_cnt; i++)
- {
- VacAttrStats *stats = &vacattrstats[i];
- bool value_hit = true;
-
-#ifdef _DROP_COLUMN_HACK__
- if (COLUMN_IS_DROPPED(stats->attr))
- continue;
-#endif /* _DROP_COLUMN_HACK__ */
- value = heap_getattr(tuple,
- stats->attr->attnum, tupDesc, &isnull);
-
- if (!VacAttrStatsEqValid(stats))
- continue;
-
- if (isnull)
- stats->null_cnt++;
- else
- {
- stats->nonnull_cnt++;
- if (stats->initialized == false)
- {
- bucketcpy(stats->attr, value, &stats->best, &stats->best_len);
- /* best_cnt gets incremented later */
- bucketcpy(stats->attr, value, &stats->guess1, &stats->guess1_len);
- stats->guess1_cnt = stats->guess1_hits = 1;
- bucketcpy(stats->attr, value, &stats->guess2, &stats->guess2_len);
- stats->guess2_hits = 1;
- if (VacAttrStatsLtGtValid(stats))
- {
- bucketcpy(stats->attr, value, &stats->max, &stats->max_len);
- bucketcpy(stats->attr, value, &stats->min, &stats->min_len);
- }
- stats->initialized = true;
- }
- if (VacAttrStatsLtGtValid(stats))
- {
- if ((*fmgr_faddr(&stats->f_cmplt)) (value, stats->min))
- {
- bucketcpy(stats->attr, value, &stats->min, &stats->min_len);
- stats->min_cnt = 0;
- }
- if ((*fmgr_faddr(&stats->f_cmpgt)) (value, stats->max))
- {
- bucketcpy(stats->attr, value, &stats->max, &stats->max_len);
- stats->max_cnt = 0;
- }
- if ((*fmgr_faddr(&stats->f_cmpeq)) (value, stats->min))
- stats->min_cnt++;
- else if ((*fmgr_faddr(&stats->f_cmpeq)) (value, stats->max))
- stats->max_cnt++;
- }
- if ((*fmgr_faddr(&stats->f_cmpeq)) (value, stats->best))
- stats->best_cnt++;
- else if ((*fmgr_faddr(&stats->f_cmpeq)) (value, stats->guess1))
- {
- stats->guess1_cnt++;
- stats->guess1_hits++;
- }
- else if ((*fmgr_faddr(&stats->f_cmpeq)) (value, stats->guess2))
- stats->guess2_hits++;
- else
- value_hit = false;
-
- if (stats->guess2_hits > stats->guess1_hits)
- {
- swapDatum(stats->guess1, stats->guess2);
- swapInt(stats->guess1_len, stats->guess2_len);
- swapLong(stats->guess1_hits, stats->guess2_hits);
- stats->guess1_cnt = stats->guess1_hits;
- }
- if (stats->guess1_cnt > stats->best_cnt)
- {
- swapDatum(stats->best, stats->guess1);
- swapInt(stats->best_len, stats->guess1_len);
- swapLong(stats->best_cnt, stats->guess1_cnt);
- stats->guess1_hits = 1;
- stats->guess2_hits = 1;
- }
- if (!value_hit)
- {
- bucketcpy(stats->attr, value, &stats->guess2, &stats->guess2_len);
- stats->guess1_hits = 1;
- stats->guess2_hits = 1;
- }
- }
- }
- return;
-}
-
-/*
- * bucketcpy() -- update pg_class statistics for one relation
- *
- */
-static void
-bucketcpy(Form_pg_attribute attr, Datum value, Datum *bucket, int *bucket_len)
-{
- if (attr->attbyval && attr->attlen != -1)
- *bucket = value;
- else
- {
- int len = (attr->attlen != -1 ? attr->attlen : VARSIZE(value));
-
- if (len > *bucket_len)
- {
- if (*bucket_len != 0)
- pfree(DatumGetPointer(*bucket));
- *bucket = PointerGetDatum(palloc(len));
- *bucket_len = len;
- }
- memmove(DatumGetPointer(*bucket), DatumGetPointer(value), len);
- }
-}
-
/*
* update_relstats() -- update statistics for one relation
*
heap_close(rd, RowExclusiveLock);
}
-/*
- * 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)))
- {
- int i;
- VacAttrStats *stats;
-
- attp = (Form_pg_attribute) GETSTRUCT(atup);
- if (attp->attnum <= 0) /* skip system attributes for now */
- continue;
-
- for (i = 0; i < natts; i++)
- {
- if (attp->attnum == vacattrstats[i].attr->attnum)
- break;
- }
- if (i >= natts)
- continue; /* skip attr if no stats collected */
- stats = &(vacattrstats[i]);
-
- if (VacAttrStatsEqValid(stats))
- {
- float32data selratio; /* average ratio of rows selected
- * for a random constant */
-
- /* Compute disbursion */
- if (stats->nonnull_cnt == 0 && stats->null_cnt == 0)
- {
-
- /*
- * empty relation, so put a dummy value in
- * attdisbursion
- */
- selratio = 0;
- }
- else if (stats->null_cnt <= 1 && stats->best_cnt == 1)
- {
- /*
- * 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
- {
- if (VacAttrStatsLtGtValid(stats) &&
- stats->min_cnt + stats->max_cnt == stats->nonnull_cnt)
- {
-
- /*
- * exact result when there are just 1 or 2
- * values...
- */
- double min_cnt_d = stats->min_cnt,
- 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;
- }
-
- /* overwrite the existing statistics in the tuple */
- attp->attdisbursion = selratio;
-
- /* invalidate the tuple in the cache and write the buffer */
- RelationInvalidateHeapTuple(ad, atup);
- WriteNoReleaseBuffer(scan->rs_cbuf);
-
- /*
- * Create pg_statistic tuples for the relation, if we have
- * gathered the right data. del_stats() previously
- * deleted all the pg_statistic tuples for the rel, so we
- * just have to insert new ones here.
- *
- * Note vacuum_rel() has seen to it that we won't come here
- * 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[]
- * ----------------
- */
- 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);
- }
- }
- }
- heap_endscan(scan);
- /* close rels, but hold locks till upcoming commit */
- heap_close(ad, NoLock);
- heap_close(sd, NoLock);
-}
-
-/*
- * del_stats() -- delete pg_statistic rows for a relation
- *
- * If a list of attribute numbers is given, only zap stats for those attrs.
- */
-static void
-del_stats(Oid relid, int attcnt, int *attnums)
-{
- Relation pgstatistic;
- HeapScanDesc scan;
- HeapTuple tuple;
- ScanKeyData key;
-
- pgstatistic = heap_openr(StatisticRelationName, RowExclusiveLock);
-
- ScanKeyEntryInitialize(&key, 0x0, Anum_pg_statistic_starelid,
- F_OIDEQ, ObjectIdGetDatum(relid));
- scan = heap_beginscan(pgstatistic, false, SnapshotNow, 1, &key);
-
- while (HeapTupleIsValid(tuple = heap_getnext(scan, 0)))
- {
- if (attcnt > 0)
- {
- Form_pg_statistic pgs = (Form_pg_statistic) GETSTRUCT(tuple);
- int i;
-
- for (i = 0; i < attcnt; i++)
- {
- if (pgs->staattnum == attnums[i] + 1)
- break;
- }
- if (i >= attcnt)
- continue; /* don't delete it */
- }
- heap_delete(pgstatistic, &tuple->t_self, NULL);
- }
-
- heap_endscan(scan);
-
- /*
- * Close rel, but *keep* lock; we will need to reacquire it later, so
- * there's a possibility of deadlock against another VACUUM process if
- * we let go now. Keeping the lock shouldn't delay any common
- * operation other than an attempted VACUUM of pg_statistic itself.
- */
- heap_close(pgstatistic, NoLock);
-}
-
/*
* reap_page() -- save a page on the array of reaped pages.
*
projects / postgresql / commitdiff