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Re: Massive parallel queue table causes index deterioration, but REINDEX fails with deadlocks. - Mailing list pgsql-performance

From Jeff Janes
Subject Re: Massive parallel queue table causes index deterioration, but REINDEX fails with deadlocks.
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Msg-id CAMkU=1x4Pxe3vD5NhSisRgOVbF=8MBA9JA2CU-Lgcuit6uQhNg@mail.gmail.com
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In response to Massive parallel queue table causes index deterioration, but REINDEX fails with deadlocks.  (Gunther <raj@gusw.net>)
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On Sat, Feb 23, 2019 at 4:06 PM Gunther <raj@gusw.net> wrote:

the dequeue operation is essentially this:

BEGIN

SELECT jobId, action
  FROM Queue 
  WHERE pending  FOR UPDATE SKIP LOCKED

There is no LIMIT shown.  Wouldn't the first thread to start up just lock all the rows and everyone else would starve?

Cheers,

Jeff
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