mirror/postgresql
2
0
Fork 0
mirror of https://git.postgresql.org/git/postgresql.git synced 2024-12-21 08:29:39 +08:00
Code Issues Packages Projects Releases Wiki Activity

Make UtilityContainsQuery recurse until it finds a non-utility Query.

Browse Source 
The callers of UtilityContainsQuery want it to return a non-utility Query
if it returns anything at all.  However, since we made CREATE TABLE
AS/SELECT INTO into a utility command instead of a variant of SELECT,
a command like "EXPLAIN SELECT INTO" results in two nested utility
statements.  So what we need UtilityContainsQuery to do is drill down
to the bottom non-utility Query.

I had thought of this possibility in setrefs.c, and fixed it there by
looping around the UtilityContainsQuery call; but overlooked that the call
sites in plancache.c have a similar issue.  In those cases it's
notationally inconvenient to provide an external loop, so let's redefine
UtilityContainsQuery as recursing down to a non-utility Query instead.

Noted by Rushabh Lathia.  This is a somewhat cleaned-up version of his
proposed patch.
This commit is contained in:
Tom Lane 2012-06-27 23:18:30 -04:00
parent f786715412
commit bde689f809
2 changed files with 21 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
src/backend/optimizer/plan/setrefs.c
View File

@ -1937,7 +1937,7 @@ extract_query_dependencies_walker(Node *node, PlannerInfo *context)
Query *query = (Query *) node;
ListCell *lc;
while (query->commandType == CMD_UTILITY)
if (query->commandType == CMD_UTILITY)
{
/*
* Ignore utility statements, except those (such as EXPLAIN) that

26
src/backend/tcop/utility.c
View File

@ -1351,25 +1351,39 @@ QueryReturnsTuples(Query *parsetree)
* UtilityContainsQuery
* Return the contained Query, or NULL if there is none
*
* Certain utility statements, such as EXPLAIN, contain a Query.
* Certain utility statements, such as EXPLAIN, contain a plannable Query.
* This function encapsulates knowledge of exactly which ones do.
* We assume it is invoked only on already-parse-analyzed statements
* (else the contained parsetree isn't a Query yet).
*
* In some cases (currently, only EXPLAIN of CREATE TABLE AS/SELECT INTO),
* potentially Query-containing utility statements can be nested. This
* function will drill down to a non-utility Query, or return NULL if none.
*/
Query *
UtilityContainsQuery(Node *parsetree)
{
Query *qry;
switch (nodeTag(parsetree))
{
case T_ExplainStmt:
Assert(IsA(((ExplainStmt *) parsetree)->query, Query));
return (Query *) ((ExplainStmt *) parsetree)->query;
qry = (Query *) ((ExplainStmt *) parsetree)->query;
Assert(IsA(qry, Query));
if (qry->commandType == CMD_UTILITY)
return UtilityContainsQuery(qry->utilityStmt);
return qry;
case T_CreateTableAsStmt:
/* might or might not contain a Query ... */
if (IsA(((CreateTableAsStmt *) parsetree)->query, Query))
return (Query *) ((CreateTableAsStmt *) parsetree)->query;
Assert(IsA(((CreateTableAsStmt *) parsetree)->query, ExecuteStmt));
qry = (Query *) ((CreateTableAsStmt *) parsetree)->query;
if (IsA(qry, Query))
{
/* Recursion currently can't be necessary here */
Assert(qry->commandType != CMD_UTILITY);
return qry;
}
Assert(IsA(qry, ExecuteStmt));
return NULL;
default: