On Fri, Dec 9, 2016 at 9:46 AM, Sreekanth Palluru <sree4pg@xxxxxxxxx> wrote: > Hi , > I am working on page corruption issue want to know if below scenario is > possible > > 1) Insert command from client , I understand heap_insert is called from > heampam.c > 2) Let us say table is full and relation is extended and added a new block > 3) Tuple is inserted into new page for the block RelationPutHeapTuple/hio.c > 4) Later WAL record is inserted through recptr = XLogInsert(RM_HEAP_ID, > info); > 5) Then backend update the PageHeader with WAL LSN details PageSetLSN(page, > recptr); > > If my server got crashed after step 4) is there a possibility that after > postgres database restart I get below error when I access the relation or > vacuum is run on this relation or taking backup through pg_dump ? > ERROR: invalid page header in block 204 of relation base/16413/16900 ? So the block is corrupted. You may want to move to another server. > or > Postgres can automatically recover the page without throwing any error ? At crash recovery, Postgres would redo things from a point where everything was consistent on disk. If this corrupted page made it to disk, there is not much that can be done except restoring from a backup. You could as well zero_damaged_pages to help here, but you would lose the data on this page, still you would be able to perform pg_dump and get back as much data as you can. At the same time, corruption can spread as well as if that's a hardware problem, so you are just seeing the beginning of a series of problems. -- Michael -- Sent via pgsql-general mailing list (pgsql-general@xxxxxxxxxxxxxx) To make changes to your subscription: http://www.postgresql.org/mailpref/pgsql-general
