On 16 February 2017 at 14:42, Amit Langote <langote_amit...@lab.ntt.co.jp> wrote: > On 2017/02/16 17:55, Amit Khandekar wrote: >> On 16 February 2017 at 12:57, Amit Langote wrote: >>> On 2017/02/16 15:50, Amit Khandekar wrote: >>>> On 15 February 2017 at 20:26, David Fetter <da...@fetter.org> wrote: >>>>> Does that make sense, and if so, is it super invasive to HINT that? >>>> >>>> Yeah, I think it should be possible to find the root partition with >>> >>> I assume you mean root *partitioned* table. >>> >>>> the help of pg_partitioned_table, >>> >>> The pg_partitioned_table catalog does not store parent-child >>> relationships, just information about the partition key of a table. To >>> get the root partitioned table, you might want to create a recursive >>> version of get_partition_parent(), maybe called >>> get_partition_root_parent(). By the way, get_partition_parent() scans >>> pg_inherits to find the inheritance parent. >> >> Yeah. But we also want to make sure that it's a part of declarative >> partition tree, and not just an inheritance tree ? I am not sure >> whether it is currently possible to have a mix of these two. May be it >> is easy to prevent that from happening. > > It is not possible to mix declarative partitioning and regular > inheritance. So, you cannot have a table in a declarative partitioning > tree that is not a (sub-) partition of the root table.
Ok, then that makes things easy. > >>>> and then run ExecFindPartition() >>>> again using the root. Will check. I am not sure right now how involved >>>> that would turn out to be, but I think that logic would not change the >>>> existing code, so in that sense it is not invasive. >>> >>> I couldn't understand why run ExecFindPartition() again on the root >>> partitioned table, can you clarify? ISTM, we just want to tell the user >>> in the HINT that trying the same update query with root partitioned table >>> might work. I'm not sure if it would work instead to find some >>> intermediate partitioned table (that is, between the root and the one that >>> update query was tried with) to include in the HINT. >> >> What I had in mind was : Give that hint only if there *was* a >> subpartition that could accommodate that row. And if found, we can >> only include the subpartition name. > > Asking to try the update query with the root table sounds like a good > enough hint. Trying to find the exact sub-partition (I assume you mean to > imply sub-tree here) seems like an overkill, IMHO. Yeah ... I was thinking , anyways it's an error condition, so why not let the server spend a bit more CPU and get the right sub-partition for the message. If we decide to write code to find the root partition, then it's just a matter of another function ExecFindPartition(). Also, I was thinking : give the hint *only* if we know there is a right sub-partition. Otherwise, it might distract the user. > > Thanks, > Amit > > -- Thanks, -Amit Khandekar EnterpriseDB Corporation The Postgres Database Company -- Sent via pgsql-hackers mailing list (firstname.lastname@example.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers