Re: Please help to speed up UPDATE statement - Mailing list pgsql-general

The following statement runs VERY slowly on large tables.

Any idea how to speed it up ?

UPDATE rid SET dokumnr=NULL WHERE
  dokumnr NOT IN (SELECT dokumnr FROM dok);

Tables:

CREATE TABLE dok ( dokumnr INTEGER,
           CONSTRAINT dok_pkey PRIMARY KEY (dokumnr) );

CREATE TABLE rid ( dokumnr INTEGER  );
CREATE INDEX rid_dokumnr_idx ON rid (dokumnr);

Andrus

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