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Fix contrib/postgres_fdw's handling of column defaults.

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Adopt the position that only locally-defined defaults matter.  Any defaults
defined in the remote database do not affect insertions performed through
a foreign table (unless they are for columns not known to the foreign
table).  While it'd arguably be more useful to permit remote defaults to be
used, making that work in a consistent fashion requires far more work than
seems possible for 9.3.
This commit is contained in:
Tom Lane
2013-03-12 18:58:13 -04:00
parent a0c6dfeecf
commit 50c19fc76f
5 changed files with 205 additions and 202 deletions
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43
contrib/postgres_fdw/postgres_fdw.c
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@ -1023,6 +1023,8 @@ postgresPlanForeignModify(PlannerInfo *root,
int subplan_index)
{
CmdType operation = plan->operation;
RangeTblEntry *rte = planner_rt_fetch(resultRelation, root);
Relation rel;
StringInfoData sql;
List *targetAttrs = NIL;
List *returningList = NIL;
@ -1030,15 +1032,33 @@ postgresPlanForeignModify(PlannerInfo *root,
initStringInfo(&sql);
/*
* Construct a list of the columns that are to be assigned during INSERT
* or UPDATE. We should transmit only these columns, for performance and
* to respect any DEFAULT values the remote side may have for other
* columns. (XXX this will need some re-thinking when we support default
* expressions for foreign tables.)
* Core code already has some lock on each rel being planned, so we can
* use NoLock here.
*/
if (operation == CMD_INSERT || operation == CMD_UPDATE)
rel = heap_open(rte->relid, NoLock);
/*
* In an INSERT, we transmit all columns that are defined in the foreign
* table. In an UPDATE, we transmit only columns that were explicitly
* targets of the UPDATE, so as to avoid unnecessary data transmission.
* (We can't do that for INSERT since we would miss sending default values
* for columns not listed in the source statement.)
*/
if (operation == CMD_INSERT)
{
TupleDesc tupdesc = RelationGetDescr(rel);
int attnum;
for (attnum = 1; attnum <= tupdesc->natts; attnum++)
{
Form_pg_attribute attr = tupdesc->attrs[attnum - 1];
if (!attr->attisdropped)
targetAttrs = lappend_int(targetAttrs, attnum);
}
}
else if (operation == CMD_UPDATE)
{
RangeTblEntry *rte = planner_rt_fetch(resultRelation, root);
Bitmapset *tmpset = bms_copy(rte->modifiedCols);
AttrNumber col;
@ -1063,21 +1083,24 @@ postgresPlanForeignModify(PlannerInfo *root,
switch (operation)
{
case CMD_INSERT:
deparseInsertSql(&sql, root, resultRelation,
deparseInsertSql(&sql, root, resultRelation, rel,
targetAttrs, returningList);
break;
case CMD_UPDATE:
deparseUpdateSql(&sql, root, resultRelation,
deparseUpdateSql(&sql, root, resultRelation, rel,
targetAttrs, returningList);
break;
case CMD_DELETE:
deparseDeleteSql(&sql, root, resultRelation, returningList);
deparseDeleteSql(&sql, root, resultRelation, rel,
returningList);
break;
default:
elog(ERROR, "unexpected operation: %d", (int) operation);
break;
}
heap_close(rel, NoLock);
/*
* Build the fdw_private list that will be available to the executor.
* Items in the list must match enum FdwModifyPrivateIndex, above.