Good day!
We have been learning more about postgres recovery, and I have come across a couple questions that google has not satisfactorily answered for me.
1. pg_waldump refuses to dump a WAL saying "fatal: WAL segment size must be a power of two between 1 MB and 1 GB", even though I have successfully used the WALs for PITR. What's the magic trick to get around this fatal error? I tried using a key unwrap function (same as in postgresql.conf) to no avail.
2. As I cannot dump the WALs, how do I determine the LSN or XID of a transaction in the past?
3. When restoring forward, I have found recovery_target_time does not work very well (maybe lack of granularity?), and recovery_target_lsn is better, but pg_current_wal_lsn() only gives me the LSN before a transaction. Is there a way to get the XID of a specific transaction?
4. How would I get the OID of a database and a table when the database is down? I wish to map the filesystem names to database objects after a crash. Is there a tool/app that can parse pg datafiles? I have to assume that if there is not already one, it is not too hard to write such a tool if one has experience with PG file headers and reading the opensource code.
Thanks for your time and attention!
