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Re: foreign key constraint, planner ignore index.

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Andrew Nesheret wrote:

And if i'm execute same statement without access to nodes table planer chose to use index "fki_nodes"!!!

explain analyze SELECT 1 FROM ONLY "public"."sf_ipv4traffic" x WHERE 2003 OPERATOR(pg_catalog.=) "node" FOR SHARE OF x;

QUERY PLAN ---------------------------------------------------------------------------------------------------------------------------- Index Scan using fki_nodes on sf_ipv4traffic x (cost=0.00..9.65 rows=1 width=6) (actual time=0.019..0.019 rows=0 loops=1)
  Index Cond: (2003 = node)
Total runtime: 0.089 ms
(3 rows)


If you PREPARE .... then EXECUTE the same query, does it still use the index? The only thing I can think of is that the trigger is planning the query to work for any given value and you have a lot of rows with e.g. node=2004.

--
  Richard Huxton
  Archonet Ltd

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