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| author | Michael Paquier <michael@paquier.xyz> | 2020-12-30 21:23:24 +0900 |
|---|---|---|
| committer | Michael Paquier <michael@paquier.xyz> | 2020-12-30 21:23:24 +0900 |
| commit | e665769e6d1e84b6650f53ed297058fc11152f7f (patch) | |
| tree | 82a4f55f692707741f6397cedeb8e02894ac69aa /src/backend/commands/explain.c | |
| parent | 0aa8a01d04c8fe200b7a106878eebc3d0af9105c (diff) | |
| download | postgresql-e665769e6d1e84b6650f53ed297058fc11152f7f.tar.gz postgresql-e665769e6d1e84b6650f53ed297058fc11152f7f.zip | |
Sanitize IF NOT EXISTS in EXPLAIN for CTAS and matviews
IF NOT EXISTS was ignored when specified in an EXPLAIN query for CREATE
MATERIALIZED VIEW or CREATE TABLE AS. Hence, if this clause was
specified, the caller would get a failure if the relation already
exists instead of a success with a NOTICE message.
This commit makes the behavior of IF NOT EXISTS in EXPLAIN consistent
with the non-EXPLAIN'd DDL queries, preventing a failure with IF NOT
EXISTS if the relation to-be-created already exists. The skip is done
before the SELECT query used for the relation is planned or executed,
and a "dummy" plan is generated instead depending on the format used by
EXPLAIN.
Author: Bharath Rupireddy
Reviewed-by: Zhijie Hou, Michael Paquier
Discussion: https://postgr.es/m/CALj2ACVa3oJ9O_wcGd+FtHWZds04dEKcakxphGz5POVgD4wC7Q@mail.gmail.com
Diffstat (limited to 'src/backend/commands/explain.c')
| -rw-r--r-- | src/backend/commands/explain.c | 16 |
1 files changed, 16 insertions, 0 deletions
diff --git a/src/backend/commands/explain.c b/src/backend/commands/explain.c index 43f9b01e833..d797b5f53e0 100644 --- a/src/backend/commands/explain.c +++ b/src/backend/commands/explain.c @@ -435,6 +435,22 @@ ExplainOneUtility(Node *utilityStmt, IntoClause *into, ExplainState *es, CreateTableAsStmt *ctas = (CreateTableAsStmt *) utilityStmt; List *rewritten; + /* + * Check if the relation exists or not. This is done at this stage to + * avoid query planning or execution. + */ + if (CreateTableAsRelExists(ctas)) + { + if (ctas->objtype == OBJECT_TABLE) + ExplainDummyGroup("CREATE TABLE AS", NULL, es); + else if (ctas->objtype == OBJECT_MATVIEW) + ExplainDummyGroup("CREATE MATERIALIZED VIEW", NULL, es); + else + elog(ERROR, "unexpected object type: %d", + (int) ctas->objtype); + return; + } + rewritten = QueryRewrite(castNode(Query, copyObject(ctas->query))); Assert(list_length(rewritten) == 1); ExplainOneQuery(linitial_node(Query, rewritten), |