Attached is a rebased and cleaned-up version of these patches, with more comments, refactorings etc. Justin and Zhihong, can you take a look?
0001 - Ignore extended statistics for inheritance trees
0002 - Build inherited extended stats on partitioned tables
Those are mostly just Justin's patches, with more detailed comments and updated commit message. I've considered moving the rel->inh check to statext_clauselist_selectivity, and then removing the check from dependencies and MCV. But I decided no to do that, because someone might be calling those functions directly (even if that's very unlikely).
The one thing bugging me a bit is that the regression test checks only a GROUP BY query. It'd be nice to add queries testing MCV/dependencies too, but that seems tricky because most queries will use per-partitions stats.
0003 - Add stxdinherit flag to pg_statistic_ext_data
This is the patch for master, allowing to build stats for both inherits flag values. It adds the flag to pg_stats_ext_exprs view to, reworked how we deal with iterating both flags etc. I've adopted most of the Justin's fixup patches, except that in plancat.c I've refactored how we load the stats to process keys/expressions just once.
It has the same issue with regression test using just a GROUP BY query, but if we add a test to 0001/0002, that'll fix this too.
0004 - Refactor parent ACL check
Not sure about this - I doubt saving 30 rows in an 8kB file is really worth it. Maybe it is, but then maybe we should try cleaning up the other ACL checks in this file too? Seems mostly orthogonal to this thread, though.
Hi,
For patch 3, in commit message:
and there no clear winner. -> and there is no clear winner.
and it seem wasteful -> and it seems wasteful
The there may be -> There may be
+ /* skip statistics with mismatching stxdinherit value */ + if (stat->inherit != rte->inh)
Should a log be added for the above case ?
+ * Determine if we'redealing with inheritance tree.