Allan Tong <[EMAIL PROTECTED]> writes: > I'm not sure if this is the right list to send this, but any help > would be appreciated. We recently encountered a problem running > postgres where, after a vacuum, all the data in one of our tables > was gone. Now, I guess technically we don't know for sure if it > was indeed vacuum that caused the data loss, but it seems likely.
The vacuum output shows that it thought it was removing only 27 out of the nearly 700K rows. So I don't think vacuum is directly to blame. However, it would very possibly have rewritten many of the pages in your table, as a byproduct of moving rows, updating tuple commit bits, etc. > ... when I looked at the file contents, it was almost > completely null'ed, so it looks like the data is really gone (though > shouldn't a full vacuum reclaim the space?). You mean the pages were all-zero? It sounds to me like a serious hardware failure, or possibly kernel/filesystem misfeasance. Postgres would certainly not have written zeroes, but apparently what got dropped onto the disk platter was zeroes. Such failures are uncommon, but by no means un-heard-of. I'd suggest running some read/write disk tests to start with. Also check for kernel errata. regards, tom lane ---------------------------(end of broadcast)--------------------------- TIP 5: Have you checked our extensive FAQ? http://www.postgresql.org/docs/faqs/FAQ.html