Horton

Re: pgsql: Add parallel-aware hash joins.

Tom Lane <tgl@sss.pgh.pa.us>

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From: Tom Lane <tgl@sss.pgh.pa.us>
To: Andres Freund <andres@anarazel.de>
Cc: Robert Haas <robertmhaas@gmail.com>, Thomas Munro <thomas.munro@enterprisedb.com>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2018-01-04T20:16:15Z
Lists: pgsql-hackers 
Andres Freund <andres@anarazel.de> writes:
> On 2018-01-04 11:20:33 -0800, Andres Freund wrote:
>> Some packages on skink have been upgraded. It appears that there either
>> was a libc or valgrind change that made valgrind not recognize that a
>> pointer of 0 might not point anywhere :(

> ==5718== Invalid write of size 8
> ==5718==    at 0x40E3DD: ExecInterpExpr (execExprInterp.c:1117)
> ==5718==    by 0x40F5E9: ExecInterpExprStillValid (execExprInterp.c:1788)
> ==5718==    by 0xE6B0409: ExecEvalExpr (executor.h:282)

Are those line numbers supposed to match current HEAD?  1117 does not
contain any write AFAICS:

	if (!op->d.iocoerce.finfo_in->fn_strict || str != NULL)

> ==5718== Process terminating with default action of signal 11 (SIGSEGV)
> ==5718==  Access not within mapped region at address 0x20
> ==5718==    at 0x40E3DD: ExecInterpExpr (execExprInterp.c:1117)
> ==5718==    by 0x40F5E9: ExecInterpExprStillValid (execExprInterp.c:1788)

This would be consistent with op->d.iocoerce.finfo_in being NULL, I think,
but there is no way that execExpr.c could have created an EEOP_IOCOERCE
step without filling in the finfo_in pointer.

I think the correct conclusion is that this version of valgrind is
buggy as hell.  I wouldn't clutter our code with suppressions trying
to make it sort-of work.

			regards, tom lane

Commits

  1. Update obsolete sentence in README.parallel.

  2. Rewrite ConditionVariableBroadcast() to avoid live-lock.

  3. Tweak parallel hash join test case in hopes of improving stability.

  4. Rename pg_rewind's copy_file_range() to avoid conflict with new linux syscall.

  5. Fix some minor errors in new PHJ code.

  6. Fix EXPLAIN ANALYZE output for Parallel Hash.

  7. Fix rare assertion failure in parallel hash join.

  8. Cancel CV sleep during subtransaction abort.

  9. Add parallel-aware hash joins.

  10. Fix EXPLAIN ANALYZE of hash join when the leader doesn't participate.

  11. Add some regression tests that exercise hash join code.