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Allow foreign tables to participate in inheritance.

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Foreign tables can now be inheritance children, or parents.  Much of the
system was already ready for this, but we had to fix a few things of
course, mostly in the area of planner and executor handling of row locks.

As side effects of this, allow foreign tables to have NOT VALID CHECK
constraints (and hence to accept ALTER ... VALIDATE CONSTRAINT), and to
accept ALTER SET STORAGE and ALTER SET WITH/WITHOUT OIDS.  Continuing to
disallow these things would've required bizarre and inconsistent special
cases in inheritance behavior.  Since foreign tables don't enforce CHECK
constraints anyway, a NOT VALID one is a complete no-op, but that doesn't
mean we shouldn't allow it.  And it's possible that some FDWs might have
use for SET STORAGE or SET WITH OIDS, though doubtless they will be no-ops
for most.

An additional change in support of this is that when a ModifyTable node
has multiple target tables, they will all now be explicitly identified
in EXPLAIN output, for example:

 Update on pt1  (cost=0.00..321.05 rows=3541 width=46)
   Update on pt1
   Foreign Update on ft1
   Foreign Update on ft2
   Update on child3
   ->  Seq Scan on pt1  (cost=0.00..0.00 rows=1 width=46)
   ->  Foreign Scan on ft1  (cost=100.00..148.03 rows=1170 width=46)
   ->  Foreign Scan on ft2  (cost=100.00..148.03 rows=1170 width=46)
   ->  Seq Scan on child3  (cost=0.00..25.00 rows=1200 width=46)

This was done mainly to provide an unambiguous place to attach "Remote SQL"
fields, but it is useful for inherited updates even when no foreign tables
are involved.

Shigeru Hanada and Etsuro Fujita, reviewed by Ashutosh Bapat and Kyotaro
Horiguchi, some additional hacking by me
This commit is contained in:
Tom Lane
2015-03-22 13:53:11 -04:00
parent 8ac356cde3
commit cb1ca4d800
29 changed files with 1764 additions and 188 deletions
Download Patch File Download Diff File Expand all files Collapse all files

80
src/backend/optimizer/plan/planner.c
View File

@ -2224,35 +2224,7 @@ preprocess_rowmarks(PlannerInfo *root)
newrc = makeNode(PlanRowMark);
newrc->rti = newrc->prti = rc->rti;
newrc->rowmarkId = ++(root->glob->lastRowMarkId);
if (rte->relkind == RELKIND_FOREIGN_TABLE)
{
/* For now, we force all foreign tables to use ROW_MARK_COPY */
newrc->markType = ROW_MARK_COPY;
}
else
{
/* regular table, apply the appropriate lock type */
switch (rc->strength)
{
case LCS_NONE:
/* we intentionally throw an error for LCS_NONE */
elog(ERROR, "unrecognized LockClauseStrength %d",
(int) rc->strength);
break;
case LCS_FORKEYSHARE:
newrc->markType = ROW_MARK_KEYSHARE;
break;
case LCS_FORSHARE:
newrc->markType = ROW_MARK_SHARE;
break;
case LCS_FORNOKEYUPDATE:
newrc->markType = ROW_MARK_NOKEYEXCLUSIVE;
break;
case LCS_FORUPDATE:
newrc->markType = ROW_MARK_EXCLUSIVE;
break;
}
}
newrc->markType = select_rowmark_type(rte, rc->strength);
newrc->allMarkTypes = (1 << newrc->markType);
newrc->strength = rc->strength;
newrc->waitPolicy = rc->waitPolicy;
@ -2277,12 +2249,7 @@ preprocess_rowmarks(PlannerInfo *root)
newrc = makeNode(PlanRowMark);
newrc->rti = newrc->prti = i;
newrc->rowmarkId = ++(root->glob->lastRowMarkId);
/* real tables support REFERENCE, anything else needs COPY */
if (rte->rtekind == RTE_RELATION &&
rte->relkind != RELKIND_FOREIGN_TABLE)
newrc->markType = ROW_MARK_REFERENCE;
else
newrc->markType = ROW_MARK_COPY;
newrc->markType = select_rowmark_type(rte, LCS_NONE);
newrc->allMarkTypes = (1 << newrc->markType);
newrc->strength = LCS_NONE;
newrc->waitPolicy = LockWaitBlock; /* doesn't matter */
@ -2294,6 +2261,49 @@ preprocess_rowmarks(PlannerInfo *root)
root->rowMarks = prowmarks;
}
/*
* Select RowMarkType to use for a given table
*/
RowMarkType
select_rowmark_type(RangeTblEntry *rte, LockClauseStrength strength)
{
if (rte->rtekind != RTE_RELATION)
{
/* If it's not a table at all, use ROW_MARK_COPY */
return ROW_MARK_COPY;
}
else if (rte->relkind == RELKIND_FOREIGN_TABLE)
{
/* For now, we force all foreign tables to use ROW_MARK_COPY */
return ROW_MARK_COPY;
}
else
{
/* Regular table, apply the appropriate lock type */
switch (strength)
{
case LCS_NONE:
/* don't need tuple lock, only ability to re-fetch the row */
return ROW_MARK_REFERENCE;
break;
case LCS_FORKEYSHARE:
return ROW_MARK_KEYSHARE;
break;
case LCS_FORSHARE:
return ROW_MARK_SHARE;
break;
case LCS_FORNOKEYUPDATE:
return ROW_MARK_NOKEYEXCLUSIVE;
break;
case LCS_FORUPDATE:
return ROW_MARK_EXCLUSIVE;
break;
}
elog(ERROR, "unrecognized LockClauseStrength %d", (int) strength);
return ROW_MARK_EXCLUSIVE; /* keep compiler quiet */
}
}
/*
* preprocess_limit - do pre-estimation for LIMIT and/or OFFSET clauses
*

10
src/backend/optimizer/prep/prepunion.c
View File

@ -1337,12 +1337,13 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
/*
* Build an RTE for the child, and attach to query's rangetable list.
* We copy most fields of the parent's RTE, but replace relation OID,
* and set inh = false. Also, set requiredPerms to zero since all
* required permissions checks are done on the original RTE.
* We copy most fields of the parent's RTE, but replace relation OID
* and relkind, and set inh = false. Also, set requiredPerms to zero
* since all required permissions checks are done on the original RTE.
*/
childrte = copyObject(rte);
childrte->relid = childOID;
childrte->relkind = newrelation->rd_rel->relkind;
childrte->inh = false;
childrte->requiredPerms = 0;
parse->rtable = lappend(parse->rtable, childrte);
@ -1388,7 +1389,8 @@ expand_inherited_rtentry(PlannerInfo *root, RangeTblEntry *rte, Index rti)
newrc->rti = childRTindex;
newrc->prti = rti;
newrc->rowmarkId = oldrc->rowmarkId;
newrc->markType = oldrc->markType;
/* Reselect rowmark type, because relkind might not match parent */
newrc->markType = select_rowmark_type(childrte, oldrc->strength);
newrc->allMarkTypes = (1 << newrc->markType);
newrc->strength = oldrc->strength;
newrc->waitPolicy = oldrc->waitPolicy;