Horton

Re: pgsql: Add parallel-aware hash joins.

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

View thread View on postgr.es
From: Tom Lane <tgl@sss.pgh.pa.us>
To: Robert Haas <robertmhaas@gmail.com>
Cc: Thomas Munro <thomas.munro@enterprisedb.com>, Andres Freund <andres@anarazel.de>, "pgsql-hackers@postgresql.org" <pgsql-hackers@postgresql.org>
Date: 2018-01-04T17:11:37Z
Lists: pgsql-hackers 
Robert Haas <robertmhaas@gmail.com> writes:
> On Thu, Jan 4, 2018 at 11:00 AM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
>> Also, what the devil is happening on skink?

> So, skink is apparently dying during shutdown of a user-connected
> backend, and specifically the one that executed the 'tablespace' test.

Well, yeah, valgrind is burping: the postmaster log is full of

==10544== VALGRINDERROR-BEGIN
==10544== Syscall param epoll_pwait(sigmask) points to unaddressable byte(s)
==10544==    at 0x7011490: epoll_pwait (epoll_pwait.c:42)
==10544==    by 0x4BF40B: WaitEventSetWaitBlock (latch.c:1048)
==10544==    by 0x4BF40B: WaitEventSetWait (latch.c:1000)
==10544==    by 0x3C0B3B: secure_read (be-secure.c:166)
==10544==    by 0x3CCD9E: pq_recvbuf (pqcomm.c:963)
==10544==    by 0x3CDA07: pq_getbyte (pqcomm.c:1006)
==10544==    by 0x4E2A2D: SocketBackend (postgres.c:339)
==10544==    by 0x4E444E: ReadCommand (postgres.c:512)
==10544==    by 0x4E7588: PostgresMain (postgres.c:4085)
==10544==    by 0x4641D0: BackendRun (postmaster.c:4412)
==10544==    by 0x467308: BackendStartup (postmaster.c:4084)
==10544==    by 0x4675F7: ServerLoop (postmaster.c:1757)
==10544==    by 0x4689D4: PostmasterMain (postmaster.c:1365)
==10544==  Address 0x0 is not stack'd, malloc'd or (recently) free'd
==10544== 
==10544== VALGRINDERROR-END

But (a) this is happening in multiple branches, and (b) we've not
changed anything near that code in awhile.  I think something broke
in valgrind itself.

			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.