Movatterモバイル変換

[0]ホーム
URL:

Skip to content

Navigation Menu

Sign in
Appearance settings

Search code, repositories, users, issues, pull requests...

Provide feedback

We read every piece of feedback, and take your input very seriously.

Saved searches

Use saved searches to filter your results more quickly

 Sign up
Appearance settings

Commitb88ef20

Browse files
committed
postgres_fdw: Refactor deparsing code for locking clauses.
The upcoming patch to allow join pushdown in postgres_fdw needs to usethis code multiple times, which requires moving it to deparse.c. Thatseems like a good idea anyway, so do that now both on general principleand to simplify the future patch.Inspired by a patch by Shigeru Hanada and Ashutosh Bapat, but I didit a little differently than what that patch did.
1 parentfbe5a3f commitb88ef20

File tree

3 files changed

+64
-49
lines changed

3 files changed

+64
-49
lines changed

‎contrib/postgres_fdw/deparse.c

Lines changed: 60 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -45,7 +45,9 @@
4545
#include"catalog/pg_type.h"
4646
#include"commands/defrem.h"
4747
#include"nodes/nodeFuncs.h"
48+
#include"nodes/plannodes.h"
4849
#include"optimizer/clauses.h"
50+
#include"optimizer/prep.h"
4951
#include"optimizer/var.h"
5052
#include"parser/parsetree.h"
5153
#include"utils/builtins.h"
@@ -807,6 +809,64 @@ deparseTargetList(StringInfo buf,
807809
appendStringInfoString(buf,"NULL");
808810
}
809811

812+
/*
813+
* Deparse the appropriate locking clause (FOR SELECT or FOR SHARE) for a
814+
* given relation.
815+
*/
816+
void
817+
deparseLockingClause(StringInfobuf,PlannerInfo*root,RelOptInfo*rel)
818+
{
819+
/*
820+
* Add FOR UPDATE/SHARE if appropriate. We apply locking during the
821+
* initial row fetch, rather than later on as is done for local tables.
822+
* The extra roundtrips involved in trying to duplicate the local
823+
* semantics exactly don't seem worthwhile (see also comments for
824+
* RowMarkType).
825+
*
826+
* Note: because we actually run the query as a cursor, this assumes that
827+
* DECLARE CURSOR ... FOR UPDATE is supported, which it isn't before 8.3.
828+
*/
829+
if (rel->relid==root->parse->resultRelation&&
830+
(root->parse->commandType==CMD_UPDATE||
831+
root->parse->commandType==CMD_DELETE))
832+
{
833+
/* Relation is UPDATE/DELETE target, so use FOR UPDATE */
834+
appendStringInfoString(buf," FOR UPDATE");
835+
}
836+
else
837+
{
838+
PlanRowMark*rc=get_plan_rowmark(root->rowMarks,rel->relid);
839+
840+
if (rc)
841+
{
842+
/*
843+
* Relation is specified as a FOR UPDATE/SHARE target, so handle
844+
* that. (But we could also see LCS_NONE, meaning this isn't a
845+
* target relation after all.)
846+
*
847+
* For now, just ignore any [NO] KEY specification, since (a) it's
848+
* not clear what that means for a remote table that we don't have
849+
* complete information about, and (b) it wouldn't work anyway on
850+
* older remote servers. Likewise, we don't worry about NOWAIT.
851+
*/
852+
switch (rc->strength)
853+
{
854+
caseLCS_NONE:
855+
/* No locking needed */
856+
break;
857+
caseLCS_FORKEYSHARE:
858+
caseLCS_FORSHARE:
859+
appendStringInfoString(buf," FOR SHARE");
860+
break;
861+
caseLCS_FORNOKEYUPDATE:
862+
caseLCS_FORUPDATE:
863+
appendStringInfoString(buf," FOR UPDATE");
864+
break;
865+
}
866+
}
867+
}
868+
}
869+
810870
/*
811871
* Deparse WHERE clauses in given list of RestrictInfos and append them to buf.
812872
*

‎contrib/postgres_fdw/postgres_fdw.c

Lines changed: 2 additions & 49 deletions
Original file line numberDiff line numberDiff line change
@@ -1013,55 +1013,8 @@ postgresGetForeignPlan(PlannerInfo *root,
10131013
if (best_path->path.pathkeys)
10141014
appendOrderByClause(&sql,root,baserel,best_path->path.pathkeys);
10151015

1016-
/*
1017-
* Add FOR UPDATE/SHARE if appropriate. We apply locking during the
1018-
* initial row fetch, rather than later on as is done for local tables.
1019-
* The extra roundtrips involved in trying to duplicate the local
1020-
* semantics exactly don't seem worthwhile (see also comments for
1021-
* RowMarkType).
1022-
*
1023-
* Note: because we actually run the query as a cursor, this assumes that
1024-
* DECLARE CURSOR ... FOR UPDATE is supported, which it isn't before 8.3.
1025-
*/
1026-
if (baserel->relid==root->parse->resultRelation&&
1027-
(root->parse->commandType==CMD_UPDATE||
1028-
root->parse->commandType==CMD_DELETE))
1029-
{
1030-
/* Relation is UPDATE/DELETE target, so use FOR UPDATE */
1031-
appendStringInfoString(&sql," FOR UPDATE");
1032-
}
1033-
else
1034-
{
1035-
PlanRowMark*rc=get_plan_rowmark(root->rowMarks,baserel->relid);
1036-
1037-
if (rc)
1038-
{
1039-
/*
1040-
* Relation is specified as a FOR UPDATE/SHARE target, so handle
1041-
* that. (But we could also see LCS_NONE, meaning this isn't a
1042-
* target relation after all.)
1043-
*
1044-
* For now, just ignore any [NO] KEY specification, since (a) it's
1045-
* not clear what that means for a remote table that we don't have
1046-
* complete information about, and (b) it wouldn't work anyway on
1047-
* older remote servers. Likewise, we don't worry about NOWAIT.
1048-
*/
1049-
switch (rc->strength)
1050-
{
1051-
caseLCS_NONE:
1052-
/* No locking needed */
1053-
break;
1054-
caseLCS_FORKEYSHARE:
1055-
caseLCS_FORSHARE:
1056-
appendStringInfoString(&sql," FOR SHARE");
1057-
break;
1058-
caseLCS_FORNOKEYUPDATE:
1059-
caseLCS_FORUPDATE:
1060-
appendStringInfoString(&sql," FOR UPDATE");
1061-
break;
1062-
}
1063-
}
1064-
}
1016+
/* Add any necessary FOR UPDATE/SHARE. */
1017+
deparseLockingClause(&sql,root,baserel);
10651018

10661019
/*
10671020
* Build the fdw_private list that will be available to the executor.

‎contrib/postgres_fdw/postgres_fdw.h

Lines changed: 2 additions & 0 deletions
Original file line numberDiff line numberDiff line change
@@ -88,6 +88,8 @@ extern void deparseSelectSql(StringInfo buf,
8888
RelOptInfo*baserel,
8989
Bitmapset*attrs_used,
9090
List**retrieved_attrs);
91+
externvoiddeparseLockingClause(StringInfobuf,
92+
PlannerInfo*root,RelOptInfo*rel);
9193
externvoidappendWhereClause(StringInfobuf,
9294
PlannerInfo*root,
9395
RelOptInfo*baserel,

0 commit comments

Comments
 (0)
[8]ページ先頭
©2009-2025 Movatter.jp