diff options
| author | Peter Eisentraut <peter_e@gmx.net> | 2017-02-17 19:32:15 -0500 |
|---|---|---|
| committer | Peter Eisentraut <peter_e@gmx.net> | 2017-02-17 19:32:15 -0500 |
| commit | e3a58c8835a2cd428b8534dd8df30a7cb96c976b (patch) | |
| tree | 94ca7efc1a9bd155b501f197ea810463498573db /src | |
| parent | 68f3dbc5525a7e78290f7dee8a74f66d5fa738d6 (diff) | |
Optimize query for information_schema.constraint_column_usage
The way the old query was written prevented some join optimizations
because the join conditions were hidden inside a CASE expression. With
a large number of constraints, the query became unreasonably slow. The
new query performs much better.
From: Alexey Bashtanov <bashtanov@imap.cc>
Reviewed-by: Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>
Diffstat (limited to 'src')
| -rw-r--r-- | src/backend/catalog/information_schema.sql | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/src/backend/catalog/information_schema.sql b/src/backend/catalog/information_schema.sql index 9a53003ecff..51795cd6ded 100644 --- a/src/backend/catalog/information_schema.sql +++ b/src/backend/catalog/information_schema.sql @@ -801,8 +801,8 @@ CREATE VIEW constraint_column_usage AS WHERE nr.oid = r.relnamespace AND r.oid = a.attrelid AND nc.oid = c.connamespace - AND (CASE WHEN c.contype = 'f' THEN r.oid = c.confrelid AND a.attnum = ANY (c.confkey) - ELSE r.oid = c.conrelid AND a.attnum = ANY (c.conkey) END) + AND r.oid = CASE c.contype WHEN 'f' THEN c.confrelid ELSE c.conrelid END + AND a.attnum = ANY (CASE c.contype WHEN 'f' THEN c.confkey ELSE c.conkey END) AND NOT a.attisdropped AND c.contype IN ('p', 'u', 'f') AND r.relkind IN ('r', 'P') |