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Integrate autovacuum functionality into the backend. There's still a

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few loose ends to be dealt with, but it seems to work.  Alvaro Herrera,
based on the contrib code by Matthew O'Connor.
This commit is contained in:
Tom Lane
2005-07-14 05:13:45 +00:00
parent f2bf2d2dc5
commit 29094193f5
25 changed files with 1678 additions and 90 deletions
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55
src/backend/commands/analyze.c
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@ -8,7 +8,7 @@
*
*
* IDENTIFICATION
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.86 2005/05/06 17:24:53 tgl Exp $
* $PostgreSQL: pgsql/src/backend/commands/analyze.c,v 1.87 2005/07/14 05:13:39 tgl Exp $
*
*-------------------------------------------------------------------------
*/
@ -29,6 +29,7 @@
#include "parser/parse_expr.h"
#include "parser/parse_oper.h"
#include "parser/parse_relation.h"
#include "pgstat.h"
#include "utils/acl.h"
#include "utils/builtins.h"
#include "utils/datum.h"
@ -77,7 +78,7 @@ static void compute_index_stats(Relation onerel, double totalrows,
MemoryContext col_context);
static VacAttrStats *examine_attribute(Relation onerel, int attnum);
static int acquire_sample_rows(Relation onerel, HeapTuple *rows,
int targrows, double *totalrows);
int targrows, double *totalrows, double *totaldeadrows);
static double random_fract(void);
static double init_selection_state(int n);
static double get_next_S(double t, int n, double *stateptr);
@ -108,7 +109,8 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt)
AnlIndexData *indexdata;
int targrows,
numrows;
double totalrows;
double totalrows,
totaldeadrows;
HeapTuple *rows;
if (vacstmt->verbose)
@ -309,6 +311,14 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt)
*/
if (attr_cnt <= 0 && !analyzableindex)
{
/*
* We report that the table is empty; this is just so that the
* autovacuum code doesn't go nuts trying to get stats about
* a zero-column table.
*/
if (!vacstmt->vacuum)
pgstat_report_analyze(RelationGetRelid(onerel), 0, 0);
vac_close_indexes(nindexes, Irel, AccessShareLock);
relation_close(onerel, AccessShareLock);
return;
@ -340,7 +350,8 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt)
* Acquire the sample rows
*/
rows = (HeapTuple *) palloc(targrows * sizeof(HeapTuple));
numrows = acquire_sample_rows(onerel, rows, targrows, &totalrows);
numrows = acquire_sample_rows(onerel, rows, targrows,
&totalrows, &totaldeadrows);
/*
* Compute the statistics. Temporary results during the calculations
@ -423,6 +434,10 @@ analyze_rel(Oid relid, VacuumStmt *vacstmt)
totalindexrows,
false);
}
/* report results to the stats collector, too */
pgstat_report_analyze(RelationGetRelid(onerel), totalrows,
totaldeadrows);
}
/* Done with indexes */
@ -752,23 +767,25 @@ BlockSampler_Next(BlockSampler bs)
* the number of different blocks represented by the sample tends to be
* too small. We can live with that for now. Improvements are welcome.
*
* We also estimate the total number of rows in the table, and return that
* into *totalrows. An important property of this sampling method is that
* because we do look at a statistically unbiased set of blocks, we should
* get an unbiased estimate of the average number of live rows per block.
* The previous sampling method put too much credence in the row density near
* the start of the table.
* We also estimate the total numbers of live and dead rows in the table,
* and return them into *totalrows and *totaldeadrows, respectively.
*
* An important property of this sampling method is that because we do
* look at a statistically unbiased set of blocks, we should get
* unbiased estimates of the average numbers of live and dead rows per
* block. The previous sampling method put too much credence in the row
* density near the start of the table.
*
* The returned list of tuples is in order by physical position in the table.
* (We will rely on this later to derive correlation estimates.)
*/
static int
acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
double *totalrows)
double *totalrows, double *totaldeadrows)
{
int numrows = 0; /* # rows collected */
double liverows = 0; /* # rows seen */
double deadrows = 0;
double deadrows = 0; /* # dead rows seen */
double rowstoskip = -1; /* -1 means not set yet */
BlockNumber totalblocks;
BlockSamplerData bs;
@ -864,11 +881,7 @@ acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
}
else
{
/*
* Count dead rows, but not empty slots. This information
* is currently not used, but it seems likely we'll want
* it someday.
*/
/* Count dead rows, but not empty slots */
if (targtuple.t_data != NULL)
deadrows += 1;
}
@ -890,12 +903,18 @@ acquire_sample_rows(Relation onerel, HeapTuple *rows, int targrows,
qsort((void *) rows, numrows, sizeof(HeapTuple), compare_rows);
/*
* Estimate total number of live rows in relation.
* Estimate total numbers of rows in relation.
*/
if (bs.m > 0)
{
*totalrows = floor((liverows * totalblocks) / bs.m + 0.5);
*totaldeadrows = floor((deadrows * totalblocks) / bs.m + 0.5);
}
else
{
*totalrows = 0.0;
*totaldeadrows = 0.0;
}
/*
* Emit some interesting relation info