Re: [COMMITTERS] pgsql: Improve memory management for external sorts.

On Fri, Mar 18, 2016 at 2:25 PM, Andres Freund <andres@anarazel.de> wrote:
> On 2016-03-17 20:11:00 +0000, Robert Haas wrote:
>> Improve memory management for external sorts.
>>
>> Introduce a new memory context which stores tuple data, and reset it
>> at the end of each merge pass; this helps avoid memory fragmentation
>> and, consequently, overallocation.  Also, for the final merge patch,
>> eliminate memory context chunk header overhead entirely by allocating
>> all of the memory used for buffering tuples during the merge in a
>> single chunk.  Since this modestly increases the number of tuples we
>> can store, grow the memtuples array a bit so that we're less likely to
>> run short of slots there.
>>
>> Peter Geoghegan.  Review and testing of patches in this series by
>> Jeff Janes, Greg Stark, Mithun Cy, and me.
>
> Cross compiling for windows results in:
> /home/andres/src/postgresql/src/backend/utils/sort/tuplesort.c: In function ‘beginmerge’:
> /home/andres/src/postgresql/src/backend/utils/sort/tuplesort.c:2695:34: warning: format ‘%ld’ expects argument of
type‘long int’, but argument 4 has type ‘int64 {aka long long int}’ [-Wformat=] 
>      elog(LOG, "tape %d initially used %ld KB of %ld KB batch "
>                                   ^
> /home/andres/src/postgresql/src/backend/utils/sort/tuplesort.c:2695:34: warning: format ‘%ld’ expects argument of
type‘long int’, but argument 5 has type ‘int64 {aka long long int}’ [-Wformat=] 
> config.status: creating src/interfaces/ecpg/include/ecpg_config.h
>
> /home/andres/src/postgresql/src/backend/utils/sort/tuplesort.c: In
> function ‘beginmerge’:
> /home/andres/src/postgresql/src/backend/utils/sort/tuplesort.c:2695:34:
> warning: format ‘%ld’ expects argument of type ‘long int’, but argument
> 4 has type ‘int64 {aka long long int}’ [-Wformat=]
>      elog(LOG, "tape %d initially used %ld KB of %ld KB batch "
>
> Which seems like a valid complain on a LLP64 platform (i.e. where long
> is 32bit) like windows.

Oops.  Thanks for the report.  Does this fix it?

--
Robert Haas
EnterpriseDB: http://www.enterprisedb.com
The Enterprise PostgreSQL Company