diff options
Diffstat (limited to 'src/backend/optimizer/prep/preptlist.c')
| -rw-r--r-- | src/backend/optimizer/prep/preptlist.c | 105 |
1 files changed, 50 insertions, 55 deletions
diff --git a/src/backend/optimizer/prep/preptlist.c b/src/backend/optimizer/prep/preptlist.c index fa56c5fc29c..f23d0554e7c 100644 --- a/src/backend/optimizer/prep/preptlist.c +++ b/src/backend/optimizer/prep/preptlist.c @@ -15,7 +15,7 @@ * Portions Copyright (c) 1994, Regents of the University of California * * IDENTIFICATION - * $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.77 2005/06/05 22:32:56 tgl Exp $ + * $PostgreSQL: pgsql/src/backend/optimizer/prep/preptlist.c,v 1.78 2005/10/15 02:49:21 momjian Exp $ * *------------------------------------------------------------------------- */ @@ -45,10 +45,10 @@ static List *expand_targetlist(List *tlist, int command_type, List * preprocess_targetlist(PlannerInfo *root, List *tlist) { - Query *parse = root->parse; - int result_relation = parse->resultRelation; - List *range_table = parse->rtable; - CmdType command_type = parse->commandType; + Query *parse = root->parse; + int result_relation = parse->resultRelation; + List *range_table = parse->rtable; + CmdType command_type = parse->commandType; /* * Sanity check: if there is a result relation, it'd better be a real @@ -63,20 +63,20 @@ preprocess_targetlist(PlannerInfo *root, List *tlist) } /* - * for heap_formtuple to work, the targetlist must match the exact - * order of the attributes. We also need to fill in any missing - * attributes. -ay 10/94 + * for heap_formtuple to work, the targetlist must match the exact order + * of the attributes. We also need to fill in any missing attributes. + * -ay 10/94 */ if (command_type == CMD_INSERT || command_type == CMD_UPDATE) tlist = expand_targetlist(tlist, command_type, result_relation, range_table); /* - * for "update" and "delete" queries, add ctid of the result relation - * into the target list so that the ctid will propagate through - * execution and ExecutePlan() will be able to identify the right - * tuple to replace or delete. This extra field is marked "junk" so - * that it is not stored back into the tuple. + * for "update" and "delete" queries, add ctid of the result relation into + * the target list so that the ctid will propagate through execution and + * ExecutePlan() will be able to identify the right tuple to replace or + * delete. This extra field is marked "junk" so that it is not stored + * back into the tuple. */ if (command_type == CMD_UPDATE || command_type == CMD_DELETE) { @@ -92,9 +92,9 @@ preprocess_targetlist(PlannerInfo *root, List *tlist) true); /* - * For an UPDATE, expand_targetlist already created a fresh tlist. - * For DELETE, better do a listCopy so that we don't destructively - * modify the original tlist (is this really necessary?). + * For an UPDATE, expand_targetlist already created a fresh tlist. For + * DELETE, better do a listCopy so that we don't destructively modify + * the original tlist (is this really necessary?). */ if (command_type == CMD_DELETE) tlist = list_copy(tlist); @@ -103,31 +103,28 @@ preprocess_targetlist(PlannerInfo *root, List *tlist) } /* - * Add TID targets for rels selected FOR UPDATE/SHARE. The executor - * uses the TID to know which rows to lock, much as for UPDATE or - * DELETE. + * Add TID targets for rels selected FOR UPDATE/SHARE. The executor uses + * the TID to know which rows to lock, much as for UPDATE or DELETE. */ if (parse->rowMarks) { ListCell *l; /* - * We've got trouble if the FOR UPDATE/SHARE appears inside - * grouping, since grouping renders a reference to individual - * tuple CTIDs invalid. This is also checked at parse time, - * but that's insufficient because of rule substitution, query - * pullup, etc. + * We've got trouble if the FOR UPDATE/SHARE appears inside grouping, + * since grouping renders a reference to individual tuple CTIDs + * invalid. This is also checked at parse time, but that's + * insufficient because of rule substitution, query pullup, etc. */ CheckSelectLocking(parse, parse->forUpdate); /* - * Currently the executor only supports FOR UPDATE/SHARE at top - * level + * Currently the executor only supports FOR UPDATE/SHARE at top level */ if (PlannerQueryLevel > 1) ereport(ERROR, (errcode(ERRCODE_FEATURE_NOT_SUPPORTED), - errmsg("SELECT FOR UPDATE/SHARE is not allowed in subqueries"))); + errmsg("SELECT FOR UPDATE/SHARE is not allowed in subqueries"))); foreach(l, parse->rowMarks) { @@ -185,14 +182,13 @@ expand_targetlist(List *tlist, int command_type, tlist_item = list_head(tlist); /* - * The rewriter should have already ensured that the TLEs are in - * correct order; but we have to insert TLEs for any missing - * attributes. + * The rewriter should have already ensured that the TLEs are in correct + * order; but we have to insert TLEs for any missing attributes. * - * Scan the tuple description in the relation's relcache entry to make - * sure we have all the user attributes in the right order. We assume - * that the rewriter already acquired at least AccessShareLock on the - * relation, so we need no lock here. + * Scan the tuple description in the relation's relcache entry to make sure + * we have all the user attributes in the right order. We assume that the + * rewriter already acquired at least AccessShareLock on the relation, so + * we need no lock here. */ rel = heap_open(getrelid(result_relation, range_table), NoLock); @@ -220,23 +216,22 @@ expand_targetlist(List *tlist, int command_type, * Didn't find a matching tlist entry, so make one. * * For INSERT, generate a NULL constant. (We assume the rewriter - * would have inserted any available default value.) Also, if - * the column isn't dropped, apply any domain constraints that - * might exist --- this is to catch domain NOT NULL. + * would have inserted any available default value.) Also, if the + * column isn't dropped, apply any domain constraints that might + * exist --- this is to catch domain NOT NULL. * - * For UPDATE, generate a Var reference to the existing value of - * the attribute, so that it gets copied to the new tuple. But - * generate a NULL for dropped columns (we want to drop any - * old values). + * For UPDATE, generate a Var reference to the existing value of the + * attribute, so that it gets copied to the new tuple. But + * generate a NULL for dropped columns (we want to drop any old + * values). * - * When generating a NULL constant for a dropped column, we label - * it INT4 (any other guaranteed-to-exist datatype would do as - * well). We can't label it with the dropped column's - * datatype since that might not exist anymore. It does not - * really matter what we claim the type is, since NULL is NULL - * --- its representation is datatype-independent. This could - * perhaps confuse code comparing the finished plan to the - * target relation, however. + * When generating a NULL constant for a dropped column, we label it + * INT4 (any other guaranteed-to-exist datatype would do as well). + * We can't label it with the dropped column's datatype since that + * might not exist anymore. It does not really matter what we + * claim the type is, since NULL is NULL --- its representation is + * datatype-independent. This could perhaps confuse code + * comparing the finished plan to the target relation, however. */ Oid atttype = att_tup->atttypid; int32 atttypmod = att_tup->atttypmod; @@ -305,12 +300,12 @@ expand_targetlist(List *tlist, int command_type, } /* - * The remaining tlist entries should be resjunk; append them all to - * the end of the new tlist, making sure they have resnos higher than - * the last real attribute. (Note: although the rewriter already did - * such renumbering, we have to do it again here in case we are doing - * an UPDATE in a table with dropped columns, or an inheritance child - * table with extra columns.) + * The remaining tlist entries should be resjunk; append them all to the + * end of the new tlist, making sure they have resnos higher than the last + * real attribute. (Note: although the rewriter already did such + * renumbering, we have to do it again here in case we are doing an UPDATE + * in a table with dropped columns, or an inheritance child table with + * extra columns.) */ while (tlist_item) { |