Hi, Pavel! On Fri, May 17, 2024 at 2:02 PM Pavel Borisov <pashkin.e...@gmail.com> wrote: > On Fri, 17 May 2024 at 14:05, Alexander Korotkov <aekorot...@gmail.com> wrote: >> >> On Tue, May 14, 2024 at 5:49 PM Justin Pryzby <pry...@telsasoft.com> wrote: >> > On Thu, May 09, 2024 at 12:51:32AM +0300, Alexander Korotkov wrote: >> > > > > However, parent's table extended statistics already covers all its >> > > > > children. >> > > > >> > > > => That's the wrong explanation. It's not that "stats on the parent >> > > > table cover its children". It's that there are two types of stats: >> > > > stats for the "table hierarchy" and stats for the individual table. >> > > > That's true for single-column stats as well as for extended stats. >> > > > In both cases, that's indicated by the inh flag in the code and in the >> > > > catalog. >> > > > >> > > > The right explanation is that extended stats on partitioned tables are >> > > > not similar to indexes. Indexes on parent table are nothing other than >> > > > a mechanism to create indexes on the child tables. That's not true for >> > > > stats. >> > > > >> > > > See also my prior messages >> > > > ZiJW1g2nbQs9ekwK@pryzbyj2023 >> > > > Zi5Msg74C61DjJKW@pryzbyj2023 >> > > >> > > Yes, I understand that parents pg_statistic entry with stainherit == >> > > true includes statistics for the children. I tried to express this by >> > > word "covers". But you're right, this is the wrong explanation. >> > > >> > > Can I, please, ask you to revise the patch? >> > >> > I tried to make this clear but it'd be nice if someone (Tomas/Alvaro?) >> > would check that this says what's wanted. >> >> Thank you! >> >> I've assembled the patches with the pending fixes. >> 0001 – The patch by Dmitry Koval for fixing detection of name >> collision in SPLIT partition operation. Also, I found that name >> collision detection doesn't work well for MERGE partitions. I've >> added fix for that to this patch as well. >> 0002 -– Patch for skipping copy of extended statistics. I would >> appreciate more feedback about wording, but I'd like to get a correct >> behavior into the source tree sooner. If the docs and/or comments >> need further improvements, we can fix that later. >> >> I'm going to push both if no objections. > > Thank you for working on this patch set! > > Some minor things: > 0001: > partition_split.sql > 157 +-- Check that detection, that the new partition has the same name as one > of > 158 +-- the merged partitions, works correctly for temporary partitions > Test for split with comment for merge. Maybe better something like: > "Split partition of a temporary table when one of the partitions after split > has the same name as the partition being split"
Thank you, fixed as proposed. > 0002: > analgous -> analogous (maybe better using "like" instead of "analogous to") > heirarchy -> hierarchy Changed "are not analgous to" to "don't behave like". > alter_table.sgml: > Maybe in documentation it's better not to provide reasoning, just state how > it works: > for consistency with <command>CREATE TABLE PARTITION OF</command> -> similar > to <command>CREATE TABLE PARTITION OF</command> I'd like to keep this. This is the question, which should naturally arise when you read: "Why this is not just INCLUDING ALL?" ------ Regards, Alexander Korotkov Supabase
v3-0001-Fix-the-name-collision-detection-in-MERGE-SPLIT-p.patch
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v3-0002-Don-t-copy-extended-statistics-during-MERGE-SPLIT.patch
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