Re: expanding inheritance in partition bound order
Amit Langote <langote_amit_f8@lab.ntt.co.jp>
From: Amit Langote <Langote_Amit_f8@lab.ntt.co.jp>
To: Amit Khandekar <amitdkhan.pg@gmail.com>
Cc: Robert Haas <robertmhaas@gmail.com>,
Ashutosh Bapat <ashutosh.bapat@enterprisedb.com>,
Pg Hackers <pgsql-hackers@postgresql.org>
Date: 2017-09-11T09:56:22Z
Lists: pgsql-hackers
Attachments
- 0001-Decouple-RelationGetPartitionDispatchInfo-from-execu.patch (text/plain) patch 0001
- 0002-Make-RelationGetPartitionDispatch-expansion-order-de.patch (text/plain) patch 0002
Hi Amit, On 2017/09/11 16:16, Amit Khandekar wrote: > Thanks Amit for the patch. I am still reviewing it, but meanwhile > below are a few comments so far ... Thanks for the review. > + next_parted_idx += (list_length(*pds) - next_parted_idx - 1); > > I think this can be replaced just by : > + next_parted_idx = list_length(*pds) - 1; > Or, how about removing this variable next_parted_idx altogether ? > Instead, we can just do this : > pd->indexes[i] = -(1 + list_length(*pds)); That seems like the simplest possible way to do it. > + next_leaf_idx += (list_length(*leaf_part_oids) - next_leaf_idx); > > Didn't understand why next_leaf_idx needs to be updated in case when > the current partrelid is partitioned. I think it should be incremented > only for leaf partitions, no ? Or for that matter, again, how about > removing the variable 'next_leaf_idx' and doing this : > *leaf_part_oids = lappend_oid(*leaf_part_oids, partrelid); > pd->indexes[i] = list_length(*leaf_part_oids) - 1; Yep. Attached updated patch does it that way for both partitioned table indexes and leaf partition indexes. Thanks for pointing it out. > ----------- > > * For every partitioned table in the tree, starting with the root > * partitioned table, add its relcache entry to parted_rels, while also > * queuing its partitions (in the order in which they appear in the > * partition descriptor) to be looked at later in the same loop. This is > * a bit tricky but works because the foreach() macro doesn't fetch the > * next list element until the bottom of the loop. > > I think the above comment needs to be modified with something > explaining the relevant changed code. For e.g. there is no > parted_rels, and the "tricky" part was there earlier because of the > list being iterated and at the same time being appended. > > ------------ I think I forgot to update this comment. > I couldn't see the existing comments like "Indexes corresponding to > the internal partitions are multiplied by" anywhere in the patch. I > think those comments are still valid, and important. Again, I failed to keep this comment. Anyway, I reworded the comments a bit to describe what the code is doing more clearly. Hope you find it so too. Thanks, Amit
Commits
-
Make RelationGetPartitionDispatchInfo expand depth-first.
- 77b6b5e9ceca 11.0 landed
-
Expand partitioned tables in PartDesc order.
- 30833ba154e0 11.0 landed
-
Don't lock tables in RelationGetPartitionDispatchInfo.
- 7c0ca2900f7c 10.0 landed
- 54cde0c4c058 11.0 landed
-
Speed up dropping tables with many partitions.
- c1e0e7e1d790 10.0 cited