A few days ago my MacBook crashed. I had to erase the harddisk and restore the data from the latest Time Machine backup. After a few hours reading a book my MacBook worked as though nothing had happened – except the postgres server. On OS X the log files can be found in /Library/PostgreSQL/8.4/data/pg_log
I looked in the newest log file with
sudo less /Library/PostgreSQL/8.4/data/pg_log/postgresql-2014-01-14_152823.log
and found a PANIC log message
2014-01-14 15:28:23 CET LOG: record with zero length at 19/3DA0E2C0 2014-01-14 15:28:23 CET LOG: invalid primary checkpoint record 2014-01-14 15:28:23 CET LOG: record with zero length at 19/3DA0E27C 2014-01-14 15:28:23 CET LOG: invalid secondary checkpoint record 2014-01-14 15:28:23 CET PANIC: could not locate a valid checkpoint record
If you want to analyse the transaction log switch user to postgres and use
sudo su - postgres /Library/PostgreSQL/8.4/bin/pg_resetxlog /Library/PostgreSQL/8.4/data
In my case the transaction log was corrupt and the data didn’t matter. So I used -f to force reset
/Library/PostgreSQL/8.4/bin/pg_resetxlog -f /Library/PostgreSQL/8.4/data
See also this discussion at stackoverflow
REWOO Blog 