Re: MultiXact member wraparound protections are disabled - Mailing list pgsql-general

From AnandKumar, Karthik
Subject Re: MultiXact member wraparound protections are disabled
Date
Msg-id 89FE23BC-30E0-4C09-BA66-CE493AC496A7@classmates.com
Whole thread Raw
In response to Re: MultiXact member wraparound protections are disabled  (Alvaro Herrera <alvherre@2ndquadrant.com>)
Responses Re: MultiXact member wraparound protections are disabled  (Alvaro Herrera <alvherre@2ndquadrant.com>)
List pgsql-general
Thanks. We started seeing this error right after a SAN FC re-cable effort - so yes, that would make sense. 
We’ll do a little more digging to see if the 0000 could have gotten removed.
If that’s an older file that we have in our filesystem backups, is it safe to restore from there?




On 10/13/16, 3:30 PM, "Alvaro Herrera" <alvherre@2ndquadrant.com> wrote:

>AnandKumar, Karthik wrote:
>> root@site-db01a:/var/lib/pgsql/cmates/data # ls pg_multixact/members
>> 0000  0001  0002  0003  0004  0005  0006  0007  0008  0009  000A  000B  000C  000D  000E  000F  0010  0011  0012
0013 0014  0015  0016  0017  0018  0019  001A  001B
 
>> root@site-db01a:/var/lib/pgsql/cmates/data # ls pg_multixact/offsets
>> 0001  0002  0003  0004  0005  0006  0007  0008  0009  000A  000B
>
>> postgres@site-db01a:~ $ /usr/pgsql-9.4/bin/pg_controldata /var/lib/pgsql/cmates/data
>
>> Latest checkpoint's NextMultiXactId:  784503
>> Latest checkpoint's NextMultiOffset:  1445264
>> Latest checkpoint's oldestMultiXid:   1
>> Latest checkpoint's oldestMulti's DB: 16457
>
>This looks perfectly normal, except that the pg_multixact/offsets/0000
>file is gone.  oldestMultiXid is 1 so I don't see how could have the
>file gotten removed.  Has this been upgraded recently from a previous
>9.3 or 9.4 version?  There have been bugs in this area but they've been
>fixed now for some time.
>
>The 0000 file could have been removed manually, perhaps?
>
>-- 
>Álvaro Herrera                https://www.2ndQuadrant.com/
>PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services

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