Alvaro Herrera <alvhe...@alvh.no-ip.org> writes: > We got a very strange nbtree corruption report some time ago. This was > a btree index on a vey high churn table -- entries are updated and > deleted very quickly, so the index grows very large and also shrinks > quickly (AFAICT this is a work queue of sorts).
> The most strange thing of all is that there was this error: > ERROR: left link changed unexpectedly in block 3378 of index "index_name" > CONTEXT: automatic vacuum of table "table_name" > This was reported not once, but several dozens of times, by each new > autovacuum worker that tried to vacuum the table. > As far as I can see, there is just no way for this to happen ... much > less happen repeatedly. It's not hard to believe that that would happen repeatedly given a corrupted set of sibling links, eg deletable page A links left to page B, which links right to C, which links right to A. The question is how the index got into such a state. A dropped update during a page split would explain it (ie, B used to be A's left sibling, then at some point B got split into B and C, but A's left-link never got updated on disk). I wonder how reliable their disk+filesystem is ... regards, tom lane -- Sent via pgsql-hackers mailing list (pgsql-hackers@postgresql.org) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-hackers