On 9/19/16 2:29 AM, Knels, Udo wrote:
The difference is that V9.1 uses Nested Loop and the index table_a_pk. V9.2 and higher don’t use the index.
First thing I'd try is running a manual ANALYZE; on the upgraded database; the 9.2 plan you showed seems to be using default values, so it thinks it's going to get 100 rows when it's only getting a few.
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