Re: Review: Patch to compute Max LSN of Data Pages

Amit Kapila escribió:
>
> Friday, November 23, 2012 5:38 AM Muhammad Usama wrote:

> >- I think when finding the max LSN of single file the utility should
> > consider all relation segments.
>   Would you like to find for all relation related segments:
>   Like 12345, 12345.1 ... 12345.n    Or
>   12345, 12345.1 ... and 12345_vm, 12345.1_vm
>
>   But how about if user asks for 12345.4, do we need to find all greater
> than 12345.4?
>
>   IMHO, as this utility is not aware of relation or any other logical
>   entity and deals with only file or directory, it is okay to find
>   only for that file.

Hmm.  I think I'd expect that if I give pg_computemaxlsn a number, it
should consider that it is a relfilenode, and so it should get a list of
all segments for all forks of it.  So if I give "12345" it should get
12345, 12345.1 and so on, and also 12345_vm 12345_vm.1 and so on.
However, if what I give it is a path, i.e. it contains a slash, I think
it should only consider the specific file mentioned.  In that light, I'm
not sure that command line options chosen are the best set.


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Álvaro Herrera                http://www.2ndQuadrant.com/
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