> broadly speaking: > *) function generates same output from inputs regardless of what's > going on in the database, and has no side effects: IMMUTABLE So can I say "if a function is marked IMMUTABLE, then it should never modify database"? Is there any counter example? > *) function reads (only) from tables, or is an immutable function in > most senses but influenced from the GUC (or any other out of scope > thing): STABLE It seems if above is correct, I can say STABLE functions should never modify databases as well. > *) all other cases: VOLATILE (which is btw the default) -- Tatsuo Ishii SRA OSS, Inc. Japan English: http://www.sraoss.co.jp/index_en.php Japanese: http://www.sraoss.co.jp -- Sent via pgsql-performance mailing list (pgsql-performance@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-performance
