Re: Querying w/ join slow for large/many child tables

On 1/29/19 6:49 PM, Wells Oliver wrote:
> I have a primary parent table with a child table per week of the year
> for each week back through 2015. There are a lot of child tables. Each
> week's child table has maybe  80-110m rows.
>
> When I join to the parent table on a column, it's very slow, but when I
> manually specify the specific week's child table, it's quite fast, e.g.
>
> Slow:
> select * from foo
> join schema.mytable on foo.col = mytable.col
>
> vs. fast:
> select * from foo
> join schema.mytable_2015_wk33 as mytable on foo.col = mytable.col
>
> What's the resolution to make querying the table faster in terms of it
> finding the appropriate child table? Is it putting an index on `col` on
> each child table? Some other thing?

https://wiki.postgresql.org/wiki/Slow_Query_Questions

>
> Thank you.
>
> --
> Wells Oliver
> wells(dot)oliver(at)gmail(dot)com <mailto:wellsoliver(at)gmail(dot)com>

--
Adrian Klaver
adrian(dot)klaver(at)aklaver(dot)com