database/postgres
1
0
Fork 0
mirror of https://github.com/postgres/postgres.git synced 2025-06-27 23:21:58 +03:00
Code Activity

Don't scan partitioned tables.

Browse Source 
Partitioned tables do not contain any data; only their unpartitioned
descendents need to be scanned.  However, the partitioned tables still
need to be locked, even though they're not scanned.  To make that
work, Append and MergeAppend relations now need to carry a list of
(unscanned) partitioned relations that must be locked, and InitPlan
must lock all partitioned result relations.

Aside from the obvious advantage of avoiding some work at execution
time, this has two other advantages.  First, it may improve the
planner's decision-making in some cases since the empty relation
might throw things off.  Second, it paves the way to getting rid of
the storage for partitioned tables altogether.

Amit Langote, reviewed by me.

Discussion: http://postgr.es/m/6837c359-45c4-8044-34d1-736756335a15@lab.ntt.co.jp
This commit is contained in:
Robert Haas
2017-03-21 09:48:04 -04:00
parent d5286aa905
commit d3cc37f1d8
27 changed files with 537 additions and 164 deletions
Download Patch File Download Diff File Expand all files Collapse all files

19
src/backend/executor/nodeModifyTable.c
View File

@ -45,6 +45,7 @@
#include "foreign/fdwapi.h"
#include "miscadmin.h"
#include "nodes/nodeFuncs.h"
#include "parser/parsetree.h"
#include "storage/bufmgr.h"
#include "storage/lmgr.h"
#include "utils/builtins.h"
@ -1725,8 +1726,20 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
estate->es_result_relation_info = saved_resultRelInfo;
/* The root table RT index is at the head of the partitioned_rels list */
if (node->partitioned_rels)
{
Index root_rti;
Oid root_oid;
root_rti = linitial_int(node->partitioned_rels);
root_oid = getrelid(root_rti, estate->es_range_table);
rel = heap_open(root_oid, NoLock); /* locked by InitPlan */
}
else
rel = mtstate->resultRelInfo->ri_RelationDesc;
/* Build state for INSERT tuple routing */
rel = mtstate->resultRelInfo->ri_RelationDesc;
if (operation == CMD_INSERT &&
rel->rd_rel->relkind == RELKIND_PARTITIONED_TABLE)
{
@ -1897,6 +1910,10 @@ ExecInitModifyTable(ModifyTable *node, EState *estate, int eflags)
mtstate->ps.ps_ExprContext = NULL;
}
/* Close the root partitioned rel if we opened it above. */
if (rel != mtstate->resultRelInfo->ri_RelationDesc)
heap_close(rel, NoLock);
/*
* If needed, Initialize target list, projection and qual for ON CONFLICT
* DO UPDATE.