On 4th of March, Alvaro Herrera committed patch: auto_explain: Add logging of trigger execution Author: Kyotaro HORIGUCHI Reviewed-by: Jaime Casanova

In previous posts in this series, I talked about how to read EXPLAIN output, and what each line (operation/node) means. Now, in the final post, I will try to explain how it happens that Pg chooses "Operation X" over "Operation Y".

On 7th of February, Robert Haas committed patch: Sometimes it may be useful to get actual row counts out of EXPLAIN (ANALYZE) without paying the cost of timing every node entry/exit. With this patch, you can say EXPLAIN (ANALYZE, TIMING OFF) to get ...

On 22nd of September, Tom Lane committed patch: Make EXPLAIN ANALYZE report the numbers of rows rejected by filter steps. This provides information about the numbers of tuples that were visited but not returned by table scans, as well as the numbers of ...

September 9th, 2010 by depesz | Tags: , , , | 19 comments »

This question (and its variants) show quite often on #postgresql on IRC. People get sequential scans, and are worried that it's slow and bad. So, I hope that this blogpost will shed some light on the subject why indexes are being ...

Robert Haas wrote, and Tom Lane committed (on 2nd of August) patch which adds interesting capability: Log Message: ----------- Add ALTER TABLE ... ALTER COLUMN ... SET STATISTICS DISTINCT   Robert Haas Log message is rather terse, so what does it exactly do?