Re: Parallel Index Scans

On 12/22/2016 01:35 PM, tushar wrote:
> On 12/22/2016 09:49 AM, Amit Kapila wrote:
>> I think you can focus on the handling of array scan keys for testing.
>> In general, one of my colleagues has shown interest in testing this
>> patch and I think he has tested as well but never posted his findings.
>> I will request him to share his findings and what kind of tests he has
>> done, if any.
> Sure, We (Prabhat and I) have done some testing for this feature 
> internally but never published the test-scripts on this forum. PFA the 
> sql scripts ( along with the expected .out files) we have used for 
> testing for your ready reference.
>
> In addition we had generated the LCOV (code coverage) report and 
> compared the files which are changed for the "Parallel index scan" patch.
> You can see the numbers for  "with patch" V/s "Without patch" (.pdf 
> file is attached)
>
In addition to that, we  run the sqlsmith against PG v10+PIS (parallel 
index scan) patches and found a crash  but that is coming on plain  PG 
v10 (without applying any patches) as well

postgres=# select
            70 as c0,
            pg_catalog.has_server_privilege(
             cast(ref_0.indexdef as text),
             cast(cast(coalesce((select name from pg_catalog.pg_settings 
limit 1 offset 16)
         ,
                null) as text) as text)) as c1,
            pg_catalog.pg_export_snapshot() as c2,
            ref_0.indexdef as c3,
            ref_0.indexname as c4
          from
           pg_catalog.pg_indexes as ref_0
          where (ref_0.tablespace = ref_0.tablespace)
            or (46 = 22)
          limit 103;
TRAP: FailedAssertion("!(keylen < 64)", File: "hashfunc.c", Line: 139)
server closed the connection unexpectedly
     This probably means the server terminated abnormally
     before or while processing the request.
The connection to the server was lost. Attempting reset: 2016-12-23 
11:19:50.627 IST [2314] LOG:  server process (PID 2322) was terminated 
by signal 6: Aborted
2016-12-23 11:19:50.627 IST [2314] DETAIL:  Failed process was running: 
select
                70 as c0,
                pg_catalog.has_server_privilege(
                 cast(ref_0.indexdef as text),
                 cast(cast(coalesce((select name from 
pg_catalog.pg_settings limit 1 offset 16)
             ,
                    null) as text) as text)) as c1,
                pg_catalog.pg_export_snapshot() as c2,
                ref_0.indexdef as c3,
                ref_0.indexname as c4
              from
               pg_catalog.pg_indexes as ref_0
              where (ref_0.tablespace = ref_0.tablespace)
                or (46 = 22)
              limit 103;
2016-12-23 11:19:50.627 IST [2314] LOG:  terminating any other active 
server processes
2016-12-23 11:19:50.627 IST [2319] WARNING:  terminating connection 
because of crash of another server process
2016-12-23 11:19:50.627 IST [2319] DETAIL:  The postmaster has commanded 
this server process to roll back the current transaction and exit, 
because another server process exited abnormally and possibly corrupted 
shared memory.
2016-12-23 11:19:50.627 IST [2319] HINT:  In a moment you should be able 
to reconnect to the database and repeat your command.
2016-12-23 11:19:50.629 IST [2323] FATAL:  the database system is in 
recovery mode
Failed.
!> 2016-12-23 11:19:50.629 IST [2314] LOG:  all server processes 
terminated; reinitializing
2016-12-23 11:19:50.658 IST [2324] LOG:  database system was 
interrupted; last known up at 2016-12-23 11:19:47 IST
2016-12-23 11:19:50.810 IST [2324] LOG:  database system was not 
properly shut down; automatic recovery in progress
2016-12-23 11:19:50.812 IST [2324] LOG:  invalid record length at 
0/155E408: wanted 24, got 0
2016-12-23 11:19:50.812 IST [2324] LOG:  redo is not required
2016-12-23 11:19:50.819 IST [2324] LOG:  MultiXact member wraparound 
protections are now enabled
2016-12-23 11:19:50.822 IST [2314] LOG:  database system is ready to 
accept connections
2016-12-23 11:19:50.822 IST [2328] LOG:  autovacuum launcher started

-- 
regards,tushar