Thread: query failing with out of memory error message.
Hello all, I have a seemingly corrupt row in a table and wanted to look at it's contents. when I try to query it I get the following... db=# select * from some_table offset 411069 limit 1; ERROR: invalid memory alloc request size 4294967293 but when I select individual fields within the record I get data. Is there a way to read this row from the datafile to examine it closer? -- Joe Maldonado jmaldonado@webehosting.biz
"Joe Maldonado" <jmaldonado@webehosting.biz> writes:
> I have a seemingly corrupt row in a table and wanted to look at it's
> contents.
> when I try to query it I get the following...
> db=# select * from some_table offset 411069 limit 1;
> ERROR: invalid memory alloc request size 4294967293
> but when I select individual fields within the record I get data.
That's odd ... I'd certainly expect one or the other field of the table
to show that failure.
> Is there a way to read this row from the datafile to examine it closer?
Select "ctid" from the troublesome row to determine its block and item
number, then dump out that block with pg_filedump. If there is data
corruption it'll usually be possible to see it in the pg_filedump dump.
Another line of attack is to attach to the backend process with gdb and
set a breakpoint at errfinish (or elog if a pre-7.4 backend), and then
get a stack trace back from the error report. This will help narrow
down exactly where the bogus allocation request is coming from.
regards, tom lane
On Tue, 29 Jun 2004 22:50:56 -0400, Tom Lane <tgl@sss.pgh.pa.us> wrote: Thanks! Where can I find a version of gp_filedump compatible with 7.4? > "Joe Maldonado" <jmaldonado@webehosting.biz> writes: >> I have a seemingly corrupt row in a table and wanted to look at it's >> contents. >> when I try to query it I get the following... > >> db=# select * from some_table offset 411069 limit 1; >> ERROR: invalid memory alloc request size 4294967293 > >> but when I select individual fields within the record I get data. > > That's odd ... I'd certainly expect one or the other field of the table > to show that failure. > >> Is there a way to read this row from the datafile to examine it closer? > > Select "ctid" from the troublesome row to determine its block and item > number, then dump out that block with pg_filedump. If there is data > corruption it'll usually be possible to see it in the pg_filedump dump. > > Another line of attack is to attach to the backend process with gdb and > set a breakpoint at errfinish (or elog if a pre-7.4 backend), and then > get a stack trace back from the error report. This will help narrow > down exactly where the bogus allocation request is coming from. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 4: Don't 'kill -9' the postmaster -- -- Joe Maldonado jmaldonado@webehosting.biz
"Joe Maldonado" <jmaldonado@webehosting.biz> writes: > Where can I find a version of pg_filedump compatible with 7.4? http://sources.redhat.com/rhdb/ regards, tom lane