diff options
Diffstat (limited to 'src/backend/optimizer/prep/preptlist.c')
| -rw-r--r-- | src/backend/optimizer/prep/preptlist.c | 50 |
1 files changed, 8 insertions, 42 deletions
diff --git a/src/backend/optimizer/prep/preptlist.c b/src/backend/optimizer/prep/preptlist.c index a8464a7aa0b..2c97c71472a 100644 --- a/src/backend/optimizer/prep/preptlist.c +++ b/src/backend/optimizer/prep/preptlist.c @@ -3,14 +3,14 @@ * preptlist.c * Routines to preprocess the parse tree target list * - * This module takes care of altering the query targetlist as needed for - * INSERT, UPDATE, and DELETE queries. For INSERT and UPDATE queries, - * the targetlist must contain an entry for each attribute of the target - * relation in the correct order. For both UPDATE and DELETE queries, - * we need a junk targetlist entry holding the CTID attribute --- the - * executor relies on this to find the tuple to be replaced/deleted. - * We may also need junk tlist entries for Vars used in the RETURNING list - * and row ID information needed for EvalPlanQual checking. + * For INSERT and UPDATE queries, the targetlist must contain an entry for + * each attribute of the target relation in the correct order. For all query + * types, we may need to add junk tlist entries for Vars used in the RETURNING + * list and row ID information needed for EvalPlanQual checking. + * + * NOTE: the rewriter's rewriteTargetListIU and rewriteTargetListUD + * routines also do preprocessing of the targetlist. The division of labor + * between here and there is a bit arbitrary and historical. * * * Portions Copyright (c) 1996-2010, PostgreSQL Global Development Group @@ -78,37 +78,6 @@ preprocess_targetlist(PlannerInfo *root, List *tlist) 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. - */ - if (command_type == CMD_UPDATE || command_type == CMD_DELETE) - { - TargetEntry *tle; - Var *var; - - var = makeVar(result_relation, SelfItemPointerAttributeNumber, - TIDOID, -1, 0); - - tle = makeTargetEntry((Expr *) var, - list_length(tlist) + 1, - pstrdup("ctid"), - 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?). - */ - if (command_type == CMD_DELETE) - tlist = list_copy(tlist); - - tlist = lappend(tlist, tle); - } - - /* * Add necessary junk columns for rowmarked rels. These values are needed * for locking of rels selected FOR UPDATE/SHARE, and to do EvalPlanQual * rechecking. While we are at it, store these junk attnos in the @@ -235,9 +204,6 @@ preprocess_targetlist(PlannerInfo *root, List *tlist) * Given a target list as generated by the parser and a result relation, * add targetlist entries for any missing attributes, and ensure the * non-junk attributes appear in proper field order. - * - * NOTE: if you are tempted to put more processing here, consider whether - * it shouldn't go in the rewriter's rewriteTargetList() instead. */ static List * expand_targetlist(List *tlist, int command_type, |