Re: block-level incremental backup

Hi,

One of my colleague at EDB, Rajkumar Raghuwanshi, while testing this
feature reported an issue. He reported that if a full base-backup is
taken, and then created a database, and then took an incremental backup,
combining full backup with incremental backup is then failing.

I had a look over this issue and observed that when the new database is
created, the catalog files are copied as-is into the new directory
corresponding to a newly created database. And as they are just copied,
the LSN on those pages are not changed. Due to this incremental backup
thinks that its an existing file and thus do not copy the blocks from
these new files, leading to the failure.

I have surprised to know that even though we are creating new files from
old files, we kept the LSN unmodified. I didn't see any other parameter
in basebackup which tells that this is a new file from last LSN or
something.

I tried looking for any other DDL doing similar stuff like creating a new
page with existing LSN. But I could not find any other commands than
CREATE DATABASE and ALTER DATABASE .. SET TABLESPACE.

Suggestions/thoughts?

--
Jeevan Chalke
Technical Architect, Product Development
EnterpriseDB Corporation
The Enterprise PostgreSQL Company