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Re: Write Ahead Logging for Hash Indexes - Mailing list pgsql-hackers

From Jeff Janes
Subject Re: Write Ahead Logging for Hash Indexes
Date
Msg-id CAMkU=1zGcfNTWWxnud8j_p0vb1ENGcngkwqZgPUEnwZmAN+XQw@mail.gmail.com
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In response to Re: Write Ahead Logging for Hash Indexes  (Amit Kapila <amit.kapila16@gmail.com>)
Responses Re: Write Ahead Logging for Hash Indexes  (Amit Kapila <amit.kapila16@gmail.com>)
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On Thu, Sep 15, 2016 at 11:42 PM, Amit Kapila <amit.kapila16@gmail.com> wrote:

Okay, Thanks for pointing out the same.  I have fixed it.  Apart from
that, I have changed _hash_alloc_buckets() to initialize the page
instead of making it completely Zero because of problems discussed in
another related thread [1].  I have also updated README.


with v7 of the concurrent has patch and v4 of the write ahead log patch and the latest relcache patch (I don't know how important that is to reproducing this, I suspect it is not), I once got this error:


38422  00000 2016-09-19 16:25:50.055 PDT:LOG:  database system was interrupted; last known up at 2016-09-19 16:25:49 PDT
38422  00000 2016-09-19 16:25:50.057 PDT:LOG:  database system was not properly shut down; automatic recovery in progress
38422  00000 2016-09-19 16:25:50.057 PDT:LOG:  redo starts at 3F/2200DE90
38422  01000 2016-09-19 16:25:50.061 PDT:WARNING:  page verification failed, calculated checksum 65067 but expected 21260
38422  01000 2016-09-19 16:25:50.061 PDT:CONTEXT:  xlog redo at 3F/22053B50 for Hash/ADD_OVFL_PAGE: bmsize 4096, bmpage_found T
38422  XX001 2016-09-19 16:25:50.071 PDT:FATAL:  invalid page in block 9 of relation base/16384/17334
38422  XX001 2016-09-19 16:25:50.071 PDT:CONTEXT:  xlog redo at 3F/22053B50 for Hash/ADD_OVFL_PAGE: bmsize 4096, bmpage_found T


The original page with the invalid checksum is:

$ od 16384_17334_9
0000000 000032 000000 015420 077347 020404 000000 000030 017760
0000020 017760 020004 000000 000000 000000 000000 000000 000000
0000040 000000 000000 000000 000000 000000 000000 000000 000000
*
0017760 000007 000002 177777 177777 000007 000000 000002 177600
0020000

If I ignore the checksum failure and re-start the system, the page gets restored to be a bitmap page.

Cheers,

Jeff

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