>>=# EXPLAIN (VERBOSE, ANALYZE) SELECT * FROM test WHERE id1 = 1 AND id3 = 101; >> QUERY PLAN >> >>------------------------------------------------------------------------------------------------------------------------------- >> Index Scan using test_idx on ikedamsh.test (cost=0.42..12630.10 rows=1 >>width=18) (actual time=0.175..279.819 rows=1 loops=1) >> Output: id1, id2, id3, value >> Index Cond: (test.id1 = 1) -- Change the output. Show only >>the bound quals. >> Index Filter: (test.id3 = 101) -- New. Output quals which are >>not used as the bound quals >> Rows Removed by Index Filter: 499999 -- New. Output when ANALYZE option >>is specified >> Planning Time: 0.354 ms >> Execution Time: 279.908 ms >> (7 rows) > > I don't think we want to split these clauses. Index Cond should indicate the > conditions applied > to the index scan. Bound quals should be listed separately even though they > will have an > intersection with Index Cond. I am not sure whether Index Filter is the right > name, > maybe Index Bound Cond: But I don't know this area enough to make a final > call.
OK, I understood that it's better to only add new ones. I think "Index Filter" fits other than "Index Bound Cond" if we introduce "Rows Removed By Index Filter". > About Rows Removed by Index Filter: it's good to provide a number when > ANALYZE is > specified, but it will be also better to specify what was estimated. We do > that for (cost snd rows etc.) > but doing that somewhere in the plan output may not have a precedent. I think > we should try that > and see what others think. It's interesting! It’s an idea that can be applied not only to multi-column indexes, right? I will consider the implementation and discuss it in a new thread. However, I would like to focus on the feature to output information about multi-column indexes at first. Regards, -- Masahiro Ikeda NTT DATA CORPORATION
