Re: Are there plans to add data compression feature to postgresql?

Grzegorz Jaśkiewicz wrote:
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> On Thu, Oct 30, 2008 at 3:27 PM, Christophe <xof@thebuild.com
> <mailto:xof@thebuild.com>> wrote:
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>     I'm a bit surprised to hear that; what would pg be doing, unique to
>     it, that would cause it to be slower on a RAID-1 cluster than on a
>     plain drive?
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> yes, it is slower on mirror-raid from single drive.
> I can give you all the /proc/* dumps if you want, as far as computer
> goes, it isn't anything fancy. dual way p4, and sata drives of some sort.

O.k. that doesn't actually surprise me all that much. Software RAID 1 on
SATA Drives for specific workloads would be slower than a single drive.
It should still be faster for reads assuming some level of concurrency
but not likely faster for a single thread. Writes would be expected to
be slower because you are managing across two spindles, identical writes
and SATA is slow for that type of thing.

Joshua D. Drake

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> GJ