Thread: Help on WAL needed!

Help on WAL needed!

From
Namrata
Date:
Hi,

I want to know about the WAL. How it is used in postgreSQL and how it is implemented and how data is recovered using
WAL?

Is there any provision for fault tolerance provided in postgreSQL?

Is there any versioning of data provided in postgreSQL when we alter the table contentes ( say If I add new column to
thetable and after some time if 
I don't want new column. I want my previous table contents. Can I get it using the versioning of the data? )

Thanks in advance.
Namrata.

Re: Help on WAL needed!

From
Peter Eisentraut
Date:
Namrata writes:

> I want to know about the WAL. How it is used in postgreSQL and how it is implemented and how data is recovered using
WAL?

-> Administrator's Guide

> Is there any provision for fault tolerance provided in postgreSQL?

If you mean "hardware fault": not really.

> Is there any versioning of data provided in postgreSQL when we alter the table contentes ( say If I add new column to
thetable and after some time if 
> I don't want new column. I want my previous table contents. Can I get it using the versioning of the data? )

"Time travel" was removed several years ago, and I don't think it ever
covered schema changes.  You can do this with triggers, there should be an
example somewhere in contrib, IIRC.

--
Peter Eisentraut   peter_e@gmx.net   http://funkturm.homeip.net/~peter