Re: SortMem...

mchron(at)aueb(dot)gr wrote:
> Hi
> in the function ExecChooseHashTableSize()
> (~/src/backend/executor/nodeHash.c)
> are determined the bytes of the hash table. The correspondent code is:
>
> /*
> * Target in-memory hashtablesize in SortMem kilobytes
> */
> hash_table_bytes = SortMem *1024L
>
> (~/src/include/miscadmin.h)
> extern DLLIMPORT int SortMem;
>
> What SortMem represents? Where is evaluated and what is its value?
>
> I want to create 2 hash tables. One for the inner and one for the outer rel.
> What should be the hash_table_bytes in that case?

SortMem is a config value found in your postgresql.conf or using SHOW
SORTMEM.

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