delta copies

Fabian Cenedese Cenedese at
Mon Sep 24 06:56:24 GMT 2007

>Not necessarily.  Depending on how pg_dump works, it could be that
>small changes to the database are resulting in unnecessarily large
>changes to the dump.  Make sure you are using the uncompressed format
>because most compression algorithms defeat the delta-transfer
>algorithm almost completely.  Then you might take a look at two
>consecutive dumps and check whether records common to both appear in
>the same order in each dump.  (If pg_dump is dumping the records in a
>different order each time, that would also defeat the delta-transfer
>algorithm because no block of several consecutive records could be

I was wondering if it would be possible to add a switch (probably coupled
to -v(+) ) that would report the number of matched blocks per file. Maybe
even with the offset of the block. That of course wouldn't help much in a
production environment, but it could help while setting up the whole
backup strategy. This would have helped the original poster finding
out if rsync is working correctly.

bye  Fabi

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