| From: | Justin Pryzby <pryzby(at)telsasoft(dot)com> |
|---|---|
| To: | Zhang Mingli <zmlpostgres(at)gmail(dot)com> |
| Cc: | pgsql-hackers(at)lists(dot)postgresql(dot)org, Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us> |
| Subject: | Re: [patch]HashJoin crash |
| Date: | 2022-08-13 19:17:46 |
| Message-ID: | 20220813191746.GI26198@telsasoft.com |
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| Thread: | |
| Lists: | pgsql-hackers |
+ Tom Lane
On Fri, Aug 12, 2022 at 11:05:06PM +0800, Zhang Mingli wrote:
> I got a coredump when using hash join on a Postgres derived Database(Greenplum DB).
> And I find a way to reproduce it on Postgres.
>
> Root cause:
>
> In ExecChooseHashTableSize(), commit b154ee63bb uses func pg_nextpower2_size_t
> whose param must not be 0.
>
> sbuckets = pg_nextpower2_size_t(hash_table_bytes / bucket_size);
>
> There is a potential risk that hash_table_bytes < bucket_size in some corner cases.
>
> Reproduce sql:
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