On Mon, Apr 22, 2019 at 08:52:11PM -0400, Bruce Momjian wrote: > Well, the interesting question is whether the server will generate a > single modblock file for all WAL in pg_wal only right before we are > ready to expire some WAL, or whether modblock files will be generated > offline, perhaps independent of the server, and perhaps by aggregating > smaller modblock files. > > To throw out an idea, what if we had an executable that could generate a > modblock file by scanning a set of WAL files? How far would that take > us to meeing incremental backup needs? I can imagine db/relfilenode oid > volatility could be a problem, but might be fixable.
Well, this actually brings up a bunch of questions: * How often do we create blockmod files? Per segment, per checkpoint, at WAL deletion time (1GB?) * What is the blockmod file format? dboid, relfilenode, blocknum? Use compression? Sorted? * How do we create incremental backups? * What is the incremental backup file format? * How do we apply incremental backups to base backups? And there are some secondary questions: * Can blockmod files be merged? * Can incremental backups be merged? * Can blockmod files be used for restore prefetching? -- Bruce Momjian <br...@momjian.us> http://momjian.us EnterpriseDB http://enterprisedb.com + As you are, so once was I. As I am, so you will be. + + Ancient Roman grave inscription +
