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Revert misguided change to postgres_fdw FOR UPDATE/SHARE code.

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In commit 462bd95705, I changed postgres_fdw
to rely on get_plan_rowmark() instead of get_parse_rowmark().  I still
think that's a good idea in the long run, but as Etsuro Fujita pointed out,
it doesn't work today because planner.c forces PlanRowMarks to have
markType = ROW_MARK_COPY for all foreign tables.  There's no urgent reason
to change this in the back branches, so let's just revert that part of
yesterday's commit rather than trying to design a better solution under
time pressure.

Also, add a regression test case showing what postgres_fdw does with FOR
UPDATE/SHARE.  I'd blithely assumed there was one already, else I'd have
realized yesterday that this code didn't work.
This commit is contained in:
Tom Lane
2014-12-12 12:41:52 -05:00
parent f2e20542da
commit 1a1fb46da4
3 changed files with 45 additions and 10 deletions
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33
contrib/postgres_fdw/expected/postgres_fdw.out
View File

@@ -231,6 +231,39 @@ SELECT * FROM ft1 t1 WHERE t1.c1 = 101 AND t1.c6 = '1' AND t1.c7 >= '1';
101 | 1 | 00101 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1 | 1 | foo
(1 row)
-- with FOR UPDATE/SHARE
EXPLAIN (VERBOSE, COSTS false) SELECT * FROM ft1 t1 WHERE c1 = 101 FOR UPDATE;
QUERY PLAN
----------------------------------------------------------------------------------------------------------------
LockRows
Output: c1, c2, c3, c4, c5, c6, c7, c8, t1.*
-> Foreign Scan on public.ft1 t1
Output: c1, c2, c3, c4, c5, c6, c7, c8, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 101)) FOR UPDATE
(5 rows)
SELECT * FROM ft1 t1 WHERE c1 = 101 FOR UPDATE;
c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8
-----+----+-------+------------------------------+--------------------------+----+------------+-----
101 | 1 | 00101 | Fri Jan 02 00:00:00 1970 PST | Fri Jan 02 00:00:00 1970 | 1 | 1 | foo
(1 row)
EXPLAIN (VERBOSE, COSTS false) SELECT * FROM ft1 t1 WHERE c1 = 102 FOR SHARE;
QUERY PLAN
---------------------------------------------------------------------------------------------------------------
LockRows
Output: c1, c2, c3, c4, c5, c6, c7, c8, t1.*
-> Foreign Scan on public.ft1 t1
Output: c1, c2, c3, c4, c5, c6, c7, c8, t1.*
Remote SQL: SELECT "C 1", c2, c3, c4, c5, c6, c7, c8 FROM "S 1"."T 1" WHERE (("C 1" = 102)) FOR SHARE
(5 rows)
SELECT * FROM ft1 t1 WHERE c1 = 102 FOR SHARE;
c1 | c2 | c3 | c4 | c5 | c6 | c7 | c8
-----+----+-------+------------------------------+--------------------------+----+------------+-----
102 | 2 | 00102 | Sat Jan 03 00:00:00 1970 PST | Sat Jan 03 00:00:00 1970 | 2 | 2 | foo
(1 row)
-- aggregate
SELECT COUNT(*) FROM ft1 t1;
count

17
contrib/postgres_fdw/postgres_fdw.c
View File

@@ -817,7 +817,7 @@ postgresGetForeignPlan(PlannerInfo *root,
}
else
{
PlanRowMark *rc = get_plan_rowmark(root->rowMarks, baserel->relid);
RowMarkClause *rc = get_parse_rowmark(root->parse, baserel->relid);
if (rc)
{
@@ -830,18 +830,15 @@ postgresGetForeignPlan(PlannerInfo *root,
* complete information about, and (b) it wouldn't work anyway on
* older remote servers. Likewise, we don't worry about NOWAIT.
*/
switch (rc->markType)
switch (rc->strength)
{
case ROW_MARK_EXCLUSIVE:
case ROW_MARK_NOKEYEXCLUSIVE:
appendStringInfoString(&sql, " FOR UPDATE");
break;
case ROW_MARK_SHARE:
case ROW_MARK_KEYSHARE:
case LCS_FORKEYSHARE:
case LCS_FORSHARE:
appendStringInfoString(&sql, " FOR SHARE");
break;
default:
/* nothing needed */
case LCS_FORNOKEYUPDATE:
case LCS_FORUPDATE:
appendStringInfoString(&sql, " FOR UPDATE");
break;
}
}

5
contrib/postgres_fdw/sql/postgres_fdw.sql
View File

@@ -145,6 +145,11 @@ SELECT * FROM ft1 WHERE false;
-- with WHERE clause
EXPLAIN (VERBOSE, COSTS false) SELECT * FROM ft1 t1 WHERE t1.c1 = 101 AND t1.c6 = '1' AND t1.c7 >= '1';
SELECT * FROM ft1 t1 WHERE t1.c1 = 101 AND t1.c6 = '1' AND t1.c7 >= '1';
-- with FOR UPDATE/SHARE
EXPLAIN (VERBOSE, COSTS false) SELECT * FROM ft1 t1 WHERE c1 = 101 FOR UPDATE;
SELECT * FROM ft1 t1 WHERE c1 = 101 FOR UPDATE;
EXPLAIN (VERBOSE, COSTS false) SELECT * FROM ft1 t1 WHERE c1 = 102 FOR SHARE;
SELECT * FROM ft1 t1 WHERE c1 = 102 FOR SHARE;
-- aggregate
SELECT COUNT(*) FROM ft1 t1;
-- join two tables