Re: Unable to startup postgres: Could not read from file "pg_clog/00EC"

On 2020-Feb-05, Nick Renders wrote:

> Is there anything specific I should check in our postgres installation /
> database to make sure it is running ok now? Anyway to see what the
> consequences were of purging that one pg_clog file?

Losing pg_clog files is pretty bad, and should not happen; then again,
this might have been something else (ie. the file was maybe not lost).
That said, wrongly overwriting files is even worse.

By zeroing an existing pg_clog file, you marked a bunch of transactions
as aborted. Your data is now probably inconsistent, if not downright
corrupt. I would be looking for my most recent backup ...

If you're very lucky, your database might be pg_dumpable. I would try
that, followed by restoring it in a separate clean instance and seeing
what happens.

--
Álvaro Herrera https://www.2ndQuadrant.com/
PostgreSQL Development, 24x7 Support, Remote DBA, Training & Services