vacuum-reltuples-fix-v3.patch

diff --git a/contrib/pgstattuple/pgstatapprox.c b/contrib/pgstattuple/pgstatapprox.c
index 5bf0613..68211c6 100644
*** a/contrib/pgstattuple/pgstatapprox.c
--- b/contrib/pgstattuple/pgstatapprox.c
*************** statapprox_heap(Relation rel, output_typ
*** 68,74 ****
  	Buffer		vmbuffer = InvalidBuffer;
  	BufferAccessStrategy bstrategy;
  	TransactionId OldestXmin;
- 	uint64		misc_count = 0;
  
  	OldestXmin = GetOldestXmin(rel, PROCARRAY_FLAGS_VACUUM);
  	bstrategy = GetAccessStrategy(BAS_BULKREAD);
--- 68,73 ----
*************** statapprox_heap(Relation rel, output_typ
*** 153,177 ****
  			tuple.t_tableOid = RelationGetRelid(rel);
  
  			/*
! 			 * We count live and dead tuples, but we also need to add up
! 			 * others in order to feed vac_estimate_reltuples.
  			 */
  			switch (HeapTupleSatisfiesVacuum(&tuple, OldestXmin, buf))
  			{
- 				case HEAPTUPLE_RECENTLY_DEAD:
- 					misc_count++;
- 					/* Fall through */
- 				case HEAPTUPLE_DEAD:
- 					stat->dead_tuple_len += tuple.t_len;
- 					stat->dead_tuple_count++;
- 					break;
  				case HEAPTUPLE_LIVE:
  					stat->tuple_len += tuple.t_len;
  					stat->tuple_count++;
  					break;
! 				case HEAPTUPLE_INSERT_IN_PROGRESS:
! 				case HEAPTUPLE_DELETE_IN_PROGRESS:
! 					misc_count++;
  					break;
  				default:
  					elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
--- 152,172 ----
  			tuple.t_tableOid = RelationGetRelid(rel);
  
  			/*
! 			 * We follow VACUUM's lead in counting INSERT_IN_PROGRESS and
! 			 * DELETE_IN_PROGRESS tuples as "live".
  			 */
  			switch (HeapTupleSatisfiesVacuum(&tuple, OldestXmin, buf))
  			{
  				case HEAPTUPLE_LIVE:
+ 				case HEAPTUPLE_INSERT_IN_PROGRESS:
+ 				case HEAPTUPLE_DELETE_IN_PROGRESS:
  					stat->tuple_len += tuple.t_len;
  					stat->tuple_count++;
  					break;
! 				case HEAPTUPLE_DEAD:
! 				case HEAPTUPLE_RECENTLY_DEAD:
! 					stat->dead_tuple_len += tuple.t_len;
! 					stat->dead_tuple_count++;
  					break;
  				default:
  					elog(ERROR, "unexpected HeapTupleSatisfiesVacuum result");
*************** statapprox_heap(Relation rel, output_typ
*** 184,191 ****
  
  	stat->table_len = (uint64) nblocks * BLCKSZ;
  
  	stat->tuple_count = vac_estimate_reltuples(rel, false, nblocks, scanned,
! 											   stat->tuple_count + misc_count);
  
  	/*
  	 * Calculate percentages if the relation has one or more pages.
--- 179,190 ----
  
  	stat->table_len = (uint64) nblocks * BLCKSZ;
  
+ 	/*
+ 	 * Extrapolate the live-tuple count to the whole table in the same way
+ 	 * that VACUUM does.  (XXX shouldn't we also extrapolate tuple_len?)
+ 	 */
  	stat->tuple_count = vac_estimate_reltuples(rel, false, nblocks, scanned,
! 											   stat->tuple_count);
  
  	/*
  	 * Calculate percentages if the relation has one or more pages.
diff --git a/doc/src/sgml/catalogs.sgml b/doc/src/sgml/catalogs.sgml
index ef60a58..87bba31 100644
*** a/doc/src/sgml/catalogs.sgml
--- b/doc/src/sgml/catalogs.sgml
*************** SCRAM-SHA-256$<replaceable>&lt;iteration
*** 1739,1746 ****
        <entry><type>float4</type></entry>
        <entry></entry>
        <entry>
!        Number of rows in the table.  This is only an estimate used by the
!        planner.  It is updated by <command>VACUUM</command>,
         <command>ANALYZE</command>, and a few DDL commands such as
         <command>CREATE INDEX</command>.
        </entry>
--- 1739,1746 ----
        <entry><type>float4</type></entry>
        <entry></entry>
        <entry>
!        Number of live rows in the table.  This is only an estimate used by
!        the planner.  It is updated by <command>VACUUM</command>,
         <command>ANALYZE</command>, and a few DDL commands such as
         <command>CREATE INDEX</command>.
        </entry>
diff --git a/src/backend/commands/vacuum.c b/src/backend/commands/vacuum.c
index cbd6e9b..067034d 100644
*** a/src/backend/commands/vacuum.c
--- b/src/backend/commands/vacuum.c
*************** vacuum_set_xid_limits(Relation rel,
*** 771,776 ****
--- 771,779 ----
   *		we take the old value of pg_class.reltuples as a measurement of the
   *		tuple density in the unscanned pages.
   *
+  *		Note: scanned_tuples should count only *live* tuples, since
+  *		pg_class.reltuples is defined that way.
+  *
   *		This routine is shared by VACUUM and ANALYZE.
   */
  double
diff --git a/src/backend/commands/vacuumlazy.c b/src/backend/commands/vacuumlazy.c
index 6587db7..ed14db2 100644
*** a/src/backend/commands/vacuumlazy.c
--- b/src/backend/commands/vacuumlazy.c
*************** typedef struct LVRelStats
*** 115,122 ****
  	BlockNumber frozenskipped_pages;	/* # of frozen pages we skipped */
  	BlockNumber tupcount_pages; /* pages whose tuples we counted */
  	double		scanned_tuples; /* counts only tuples on tupcount_pages */
! 	double		old_rel_tuples; /* previous value of pg_class.reltuples */
  	double		new_rel_tuples; /* new estimated total # of tuples */
  	double		new_dead_tuples;	/* new estimated total # of dead tuples */
  	BlockNumber pages_removed;
  	double		tuples_deleted;
--- 115,123 ----
  	BlockNumber frozenskipped_pages;	/* # of frozen pages we skipped */
  	BlockNumber tupcount_pages; /* pages whose tuples we counted */
  	double		scanned_tuples; /* counts only tuples on tupcount_pages */
! 	double		old_live_tuples;	/* previous value of pg_class.reltuples */
  	double		new_rel_tuples; /* new estimated total # of tuples */
+ 	double		new_live_tuples;	/* new estimated total # of live tuples */
  	double		new_dead_tuples;	/* new estimated total # of dead tuples */
  	BlockNumber pages_removed;
  	double		tuples_deleted;
*************** lazy_vacuum_rel(Relation onerel, int opt
*** 196,202 ****
  	TransactionId xidFullScanLimit;
  	MultiXactId mxactFullScanLimit;
  	BlockNumber new_rel_pages;
- 	double		new_rel_tuples;
  	BlockNumber new_rel_allvisible;
  	double		new_live_tuples;
  	TransactionId new_frozen_xid;
--- 197,202 ----
*************** lazy_vacuum_rel(Relation onerel, int opt
*** 245,251 ****
  	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
  
  	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
! 	vacrelstats->old_rel_tuples = onerel->rd_rel->reltuples;
  	vacrelstats->num_index_scans = 0;
  	vacrelstats->pages_removed = 0;
  	vacrelstats->lock_waiter_detected = false;
--- 245,251 ----
  	vacrelstats = (LVRelStats *) palloc0(sizeof(LVRelStats));
  
  	vacrelstats->old_rel_pages = onerel->rd_rel->relpages;
! 	vacrelstats->old_live_tuples = onerel->rd_rel->reltuples;
  	vacrelstats->num_index_scans = 0;
  	vacrelstats->pages_removed = 0;
  	vacrelstats->lock_waiter_detected = false;
*************** lazy_vacuum_rel(Relation onerel, int opt
*** 311,321 ****
  	 * since then we don't know for certain that all tuples have a newer xmin.
  	 */
  	new_rel_pages = vacrelstats->rel_pages;
! 	new_rel_tuples = vacrelstats->new_rel_tuples;
  	if (vacrelstats->tupcount_pages == 0 && new_rel_pages > 0)
  	{
  		new_rel_pages = vacrelstats->old_rel_pages;
! 		new_rel_tuples = vacrelstats->old_rel_tuples;
  	}
  
  	visibilitymap_count(onerel, &new_rel_allvisible, NULL);
--- 311,321 ----
  	 * since then we don't know for certain that all tuples have a newer xmin.
  	 */
  	new_rel_pages = vacrelstats->rel_pages;
! 	new_live_tuples = vacrelstats->new_live_tuples;
  	if (vacrelstats->tupcount_pages == 0 && new_rel_pages > 0)
  	{
  		new_rel_pages = vacrelstats->old_rel_pages;
! 		new_live_tuples = vacrelstats->old_live_tuples;
  	}
  
  	visibilitymap_count(onerel, &new_rel_allvisible, NULL);
*************** lazy_vacuum_rel(Relation onerel, int opt
*** 327,333 ****
  
  	vac_update_relstats(onerel,
  						new_rel_pages,
! 						new_rel_tuples,
  						new_rel_allvisible,
  						vacrelstats->hasindex,
  						new_frozen_xid,
--- 327,333 ----
  
  	vac_update_relstats(onerel,
  						new_rel_pages,
! 						new_live_tuples,
  						new_rel_allvisible,
  						vacrelstats->hasindex,
  						new_frozen_xid,
*************** lazy_vacuum_rel(Relation onerel, int opt
*** 335,344 ****
  						false);
  
  	/* report results to the stats collector, too */
- 	new_live_tuples = new_rel_tuples - vacrelstats->new_dead_tuples;
- 	if (new_live_tuples < 0)
- 		new_live_tuples = 0;	/* just in case */
- 
  	pgstat_report_vacuum(RelationGetRelid(onerel),
  						 onerel->rd_rel->relisshared,
  						 new_live_tuples,
--- 335,340 ----
*************** lazy_scan_heap(Relation onerel, int opti
*** 1275,1284 ****
  	vacrelstats->new_dead_tuples = nkeep;
  
  	/* now we can compute the new value for pg_class.reltuples */
! 	vacrelstats->new_rel_tuples = vac_estimate_reltuples(onerel, false,
! 														 nblocks,
! 														 vacrelstats->tupcount_pages,
! 														 num_tuples);
  
  	/*
  	 * Release any remaining pin on visibility map page.
--- 1271,1284 ----
  	vacrelstats->new_dead_tuples = nkeep;
  
  	/* now we can compute the new value for pg_class.reltuples */
! 	vacrelstats->new_live_tuples = vac_estimate_reltuples(onerel, false,
! 														  nblocks,
! 														  vacrelstats->tupcount_pages,
! 														  num_tuples - nkeep);
! 
! 	/* indexes probably care more about the total number of heap entries */
! 	vacrelstats->new_rel_tuples =
! 		vacrelstats->new_live_tuples + vacrelstats->new_dead_tuples;
  
  	/*
  	 * Release any remaining pin on visibility map page.
*************** lazy_vacuum_index(Relation indrel,
*** 1614,1620 ****
  	ivinfo.analyze_only = false;
  	ivinfo.estimated_count = true;
  	ivinfo.message_level = elevel;
! 	ivinfo.num_heap_tuples = vacrelstats->old_rel_tuples;
  	ivinfo.strategy = vac_strategy;
  
  	/* Do bulk deletion */
--- 1614,1621 ----
  	ivinfo.analyze_only = false;
  	ivinfo.estimated_count = true;
  	ivinfo.message_level = elevel;
! 	/* We can only provide an approximate value of num_heap_tuples here */
! 	ivinfo.num_heap_tuples = vacrelstats->old_live_tuples;
  	ivinfo.strategy = vac_strategy;
  
  	/* Do bulk deletion */
*************** lazy_cleanup_index(Relation indrel,
*** 1645,1650 ****
--- 1646,1652 ----
  	ivinfo.analyze_only = false;
  	ivinfo.estimated_count = (vacrelstats->tupcount_pages < vacrelstats->rel_pages);
  	ivinfo.message_level = elevel;
+ 	/* Now we can provide a better estimate of total # of surviving tuples */
  	ivinfo.num_heap_tuples = vacrelstats->new_rel_tuples;
  	ivinfo.strategy = vac_strategy;