Re: Planning time is high in Postgres 11.5 Compared with Postgres 10.11

Hi Pavel,

Collation " en_US.UTF-8" is same on both databases. Infact both the v10 and
V11 databases are on same machine.

Can you please let us know if i need to check anything..

Thanks,
Avinash

On Tue, Dec 17, 2019 at 11:50 AM Pavel Stehule <[email protected]>
wrote:

>
>
> út 17. 12. 2019 v 7:11 odesílatel avinash varma <[email protected]>
> napsal:
>
>> Hi Tom,
>>
>>   You didn't answer the question:
>>
>> >> First thing to do is to look into pg_stats and see how large those
>> >> arrays actually are in each case ...
>>
>> We reproduced issue with sample tables "child" and "core", moreover these
>> tables  doesn't contains any data in it in both postgresql 10 & 11.
>>
>> select count(1) from child --0
>> select count(1) from core --0
>>
>> I did analyzed both the tables using the below command and after which i
>> ran the below explain analyze and took the perf report.
>>
>> Vacuum analyze child;
>> vacuum analyze core;
>>
>> Both configuration parameters are identical in V10 & V11. But we observe
>> high planning time in V11 when compared with V10.
>>
>> PostDB11=# explain analyze  SELECT --DISTINCT kc.childid AS rlid,
>> PostDB11-#     kc.id AS rlrightid--,
>> PostDB11-#    -- 0 AS rlproxytype
>> PostDB11-#    FROM child kc
>> PostDB11-#   WHERE NOT (EXISTS ( SELECT 1
>> PostDB11(#            FROM core
>> PostDB11(#           WHERE kc.id = core.groupid));
>>
>>
>> Postgres 10
>>
>> -bash-4.2$ perf report -g
>> Samples: 6K of event 'cpu-clock:uhH', Event count (approx.): 1541000000
>>   Children      Self  Command   Shared Object          Symbol
>>
>>
>>
>>
>> *+   13.72%     0.00%  postgres  [unknown]              [.]
>> 0000000000000000+    5.34%     0.08%  postgres  libc-2.17.so
>> <http://libc-2.17.so>           [.] __vsnprintf_chk+    4.62%     1.52%
>>  postgres  libc-2.17.so <http://libc-2.17.so>           [.] vfprintf+
>>  4.59%     4.59%  postgres  postgres               [.] SearchCatCache+
>>  4.12%     0.00%  postgres  [unknown]              [.] 0x0000000001d86000*
>> +    4.09%     4.09%  postgres  postgres               [.] base_yyparse
>> +    2.09%     0.00%  postgres  [unknown]              [.]
>> 0x312e2e32362e3135
>> +    2.04%     2.03%  postgres  postgres               [.]
>> hash_search_with_hash_value
>>      1.83%     1.83%  postgres  libc-2.17.so           [.] __strcmp_sse42
>> +    1.78%     0.00%  postgres  [unknown]              [.]
>> 0x0000000001d83638
>> +    1.74%     0.00%  postgres  [unknown]              [.]
>> 0x0000000000cb3260
>> +    1.49%     1.43%  postgres  libc-2.17.so           [.]
>> __GI___printf_fp_l
>>
>>
>>
>> Postgres 11
>>
>>
>> bash-4.2$ perf report -g
>> Samples: 235K of event 'cpu-clock:uhH', Event count (approx.): 58888750000
>>   Children      Self  Command   Shared Object       Symbol
>> +   37.73%    37.73%  postgres  postgres            [.] FunctionCall2Coll
>> +   28.57%    28.57%  postgres  postgres            [.] eqjoinsel
>> +   13.94%    13.94%  postgres  postgres            [.] int8eq
>> +    5.68%     5.68%  postgres  postgres            [.]
>> eqjoinsel_semi.isra.3
>> +    1.78%     0.14%  postgres  libc-2.17.so        [.] __clock_gettime
>> +    1.76%     1.76%  postgres  postgres            [.] pglz_decompress
>> +    1.68%     1.68%  postgres  [vdso]              [.]
>> __vdso_clock_gettime
>> +    1.43%     0.00%  postgres  [unknown]           [.] 0000000000000000
>> +    1.22%     0.00%  postgres  postgres            [.] TTSOpsVirtual+0x0
>> +    0.93%     0.00%  postgres  postgres            [.]
>> TTSOpsBufferHeapTuple+0x0
>> +    0.72%     0.00%  postgres  [unknown]           [.] 0x00000000026bb0d0
>>      0.44%     0.44%  postgres  postgres            [.] deconstruct_array
>>
>> Thanks,
>> Avinash
>>
>
> is same collation in both databases?
>
> Maybe there are some issues in virtualization
>
> Pavel
>


-- 
Thanks & Regards,

Avinash.