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| author | Bruce Momjian <bruce@momjian.us> | 2006-02-12 19:31:14 +0000 |
|---|---|---|
| committer | Bruce Momjian <bruce@momjian.us> | 2006-02-12 19:31:14 +0000 |
| commit | 05e27a9c20d4cd9f605e8601ca6b04be9056113e (patch) | |
| tree | 74614ead3fed9c5a2d2efe06f675eb063efbc687 | |
| parent | 7d57a1825f62a67b0eddc65d8618a9043d14f9e8 (diff) | |
| download | postgresql-05e27a9c20d4cd9f605e8601ca6b04be9056113e.tar.gz postgresql-05e27a9c20d4cd9f605e8601ca6b04be9056113e.zip | |
Remove LEFT part of JOIN to pg_roles because of optimizer limitation:
> True, but they're not being used where you'd expect. This seems to be
> something to do with the fact that it's not pg_authid which is being
> accessed, but rather the view pg_roles.
I looked into this and it seems the problem is that the view doesn't
get flattened into the main query because of the has_nullable_targetlist
limitation in prepjointree.c. That's triggered because pg_roles has
'********'::text AS rolpassword
which isn't nullable, meaning it would produce wrong behavior if
referenced above the outer join.
Ultimately, the reason this is a problem is that the planner deals only
in simple Vars while processing joins; it doesn't want to think about
expressions. I'm starting to think that it may be time to fix this,
because I've run into several related restrictions lately, but it seems
like a nontrivial project.
In the meantime, reducing the LEFT JOIN to pg_roles to a JOIN as per
Peter's suggestion seems like the best short-term workaround.
| -rw-r--r-- | src/bin/psql/describe.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/src/bin/psql/describe.c b/src/bin/psql/describe.c index 17ca722f307..1653ae2bdaf 100644 --- a/src/bin/psql/describe.c +++ b/src/bin/psql/describe.c @@ -3,7 +3,7 @@ * * Copyright (c) 2000-2005, PostgreSQL Global Development Group * - * $PostgreSQL: pgsql/src/bin/psql/describe.c,v 1.131 2006/02/12 03:22:19 momjian Exp $ + * $PostgreSQL: pgsql/src/bin/psql/describe.c,v 1.132 2006/02/12 19:31:14 momjian Exp $ */ #include "postgres_fe.h" #include "describe.h" @@ -194,7 +194,7 @@ describeFunctions(const char *pattern, bool verbose) "\nFROM pg_catalog.pg_proc p" "\n LEFT JOIN pg_catalog.pg_namespace n ON n.oid = p.pronamespace" "\n LEFT JOIN pg_catalog.pg_language l ON l.oid = p.prolang" - "\n LEFT JOIN pg_catalog.pg_roles r ON r.oid = p.proowner\n"); + "\n JOIN pg_catalog.pg_roles r ON r.oid = p.proowner\n"); /* * we skip in/out funcs by excluding functions that take or return cstring @@ -367,7 +367,7 @@ listAllDbs(bool verbose) _("Description")); appendPQExpBuffer(&buf, "\nFROM pg_catalog.pg_database d" - "\n LEFT JOIN pg_catalog.pg_roles r ON d.datdba = r.oid\n" + "\n JOIN pg_catalog.pg_roles r ON d.datdba = r.oid\n" "ORDER BY 1;"); res = PSQLexec(buf.data, false); @@ -1485,7 +1485,7 @@ listTables(const char *tabtypes, const char *pattern, bool verbose) appendPQExpBuffer(&buf, "\nFROM pg_catalog.pg_class c" - "\n LEFT JOIN pg_catalog.pg_roles r ON r.oid = c.relowner" + "\n JOIN pg_catalog.pg_roles r ON r.oid = c.relowner" "\n LEFT JOIN pg_catalog.pg_namespace n ON n.oid = c.relnamespace"); if (showIndexes) appendPQExpBuffer(&buf, @@ -1727,7 +1727,7 @@ listSchemas(const char *pattern, bool verbose) _("Access privileges"), _("Description")); appendPQExpBuffer(&buf, - "\nFROM pg_catalog.pg_namespace n LEFT JOIN pg_catalog.pg_roles r\n" + "\nFROM pg_catalog.pg_namespace n JOIN pg_catalog.pg_roles r\n" " ON n.nspowner=r.oid\n" "WHERE (n.nspname !~ '^pg_temp_' OR\n" " n.nspname = (pg_catalog.current_schemas(true))[1])\n"); /* temp schema is first */ |