Обсуждение: pqReadData() -- backend closed the channel unexpectedly.
I have a bit of an odd problem with an update statement. I have a table logs2 at 35 columns wide and a miserly 193 rows. I also have a table testtime at 4 columns wide and 2.2 million rows. When I run the following sql I get a success on testtime and a failure of "pqReadData() -- backend closed the channel unexpectedly on logs2". update <either tablename> set time2 = to_timestamp(time, 'HH24:MI:SS'); This is quite confusing to me, I have a success on updating a 2.2 million row table and a failure on a 193 row table (the smaller data set is a subset of the 2.2 million row selection). Both tables are fresh, built with a select into statement, a variety of other queries work fine with these tables. The machine has a gig of ram and a 800mb shared buffer. The sort buffer set to 16mb. What is causing this problem? How can I figure this out? I have some theories on what might be going wrong. The sort buffers are probably too small (I am working on getting my hands on the root password so I can play with this). There is some problem with version 7.0.3 that is causing the back end to drop out, but I have seen no postings on that possibility. So any advice on how to trace this problem down would be great. -Jeff Barrett
"Jeff Barrett" <jbarrett@familynetwork.com> writes: > I get a success on testtime and a failure of "pqReadData() -- backend > closed the channel unexpectedly on logs2". > update <either tablename> set time2 = to_timestamp(time, 'HH24:MI:SS'); Any NULL values in the time column? ISTR to_timestamp fails on NULLs in pre-7.1 releases. Try upgrading. regards, tom lane
Checked that out, every row has a value and the values are properly formatted. Seems like this may be an issue of not enough ram in the server. The only problem I have with that diagnosis is that I do not get an out of memory error, I just loose the back end. Thanks, Jeff "Tom Lane" <tgl@sss.pgh.pa.us> wrote in message news:12678.991063302@sss.pgh.pa.us... > "Jeff Barrett" <jbarrett@familynetwork.com> writes: > > I get a success on testtime and a failure of "pqReadData() -- backend > > closed the channel unexpectedly on logs2". > > > update <either tablename> set time2 = to_timestamp(time, 'HH24:MI:SS'); > > Any NULL values in the time column? ISTR to_timestamp fails on NULLs in > pre-7.1 releases. Try upgrading. > > regards, tom lane > > ---------------------------(end of broadcast)--------------------------- > TIP 2: you can get off all lists at once with the unregister command > (send "unregister YourEmailAddressHere" to majordomo@postgresql.org)
"Jeff Barrett" <jbarrett@familynetwork.com> writes: > Checked that out, every row has a value and the values are properly > formatted. Seems like this may be an issue of not enough ram in the server. If it's a memory leak issue, my advice is still to upgrade to 7.1. regards, tom lane