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Home > Archive > PostgreSQL Administration > September 2005 > Disk Access Question
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Disk Access Question
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| Chris Hoover 2005-09-20, 1:24 pm |
| I have a question on disk access.
How often is PostgreSQL accessing/touching the files that are on the hard
drive?
What I'm trying to ask is, is PostgreSQL constantly updating access
timestamps or something like that on the database files even if they are not
being queried? This questions comes from an Oracle background where Oracle
was updating the individual files every 3 seconds if I am remembering
correctly.
I am trying to figure out besides the queries, what sort of accessing is
PostgreSQL doing to my drives so we can try and resolve some i/o issues.
Thanks,
Chris
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| Chris Hoover 2005-09-20, 1:24 pm |
| Sorry, for got to mention pg 7.3.4.
On 9/20/05, Chris Hoover <revoohc@gmail.com> wrote:
>
> I have a question on disk access.
>
> How often is PostgreSQL accessing/touching the files that are on the hard
> drive?
>
> What I'm trying to ask is, is PostgreSQL constantly updating access
> timestamps or something like that on the database files even if they are not
> being queried? This questions comes from an Oracle background where Oracle
> was updating the individual files every 3 seconds if I am remembering
> correctly.
>
> I am trying to figure out besides the queries, what sort of accessing is
> PostgreSQL doing to my drives so we can try and resolve some i/o issues.
>
> Thanks,
>
> Chris
>
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| Robert Treat 2005-09-21, 7:24 am |
| On Tuesday 20 September 2005 13:55, Chris Hoover wrote:
> I have a question on disk access.
>
> How often is PostgreSQL accessing/touching the files that are on the hard
> drive?
>
> What I'm trying to ask is, is PostgreSQL constantly updating access
> timestamps or something like that on the database files even if they are
> not being queried? This questions comes from an Oracle background where
> Oracle was updating the individual files every 3 seconds if I am
> remembering correctly.
>
> I am trying to figure out besides the queries, what sort of accessing is
> PostgreSQL doing to my drives so we can try and resolve some i/o issues.
>
AFAIK unless your actually doing something,it wont access your data files at
all. Note that something is pretty wide here, insert/update/vacuum/analyze
and even select will cause file access but otherwise it wont.
--
Robert Treat
Build A Brighter Lamp :: Linux apache {middleware} PostgreSQL
---------------------------(end of broadcast)---------------------------
TIP 6: explain analyze is your friend
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| Gaetano Mendola 2005-09-27, 3:24 am |
| Robert Treat wrote:
> On Tuesday 20 September 2005 13:55, Chris Hoover wrote:
>
> AFAIK unless your actually doing something,it wont access your data files at
> all. Note that something is pretty wide here, insert/update/vacuum/analyze
> and even select will cause file access but otherwise it wont.
You can mount your partition ( on Linux ) specifing the "noatime" option this
will avoid your inode access time to be updated when files are only read.
Postgres do not use this information so you are safe.
Regards
Gaetano Mendola
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