Re: Anything to be gained from a 'Postgres Filesystem'?

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



lists@xxxxxxxxxxxxxxxxxxxxx (Pierre-Frédéric Caillaud) writes:
>> posix_fadvise(2) may be a candidate. Read/Write bareers another pone, as
>> well asn syncing a bunch of data in different files with a single call
>> (so that the OS can determine the best write order). I can also imagine
>> some interaction with the FS journalling system (to avoid duplicate
>> efforts).
>
> 	There is also the fact that syncing after every transaction
> could be  changed to syncing every N transactions (N fixed or
> depending on the data  size written by the transactions) which would
> be more efficient than the  current behaviour with a sleep. HOWEVER
> suppressing the sleep() would lead  to postgres returning from the
> COMMIT while it is in fact not synced,  which somehow rings a huge
> alarm bell somewhere.
>
> 	What about read order ?
> 	This could be very useful for SELECT queries involving
> indexes, which in  case of a non-clustered table lead to random seeks
> in the table.

Another thing that would be valuable would be to have some way to say:

  "Read this data; don't bother throwing other data out of the cache
   to stuff this in."

Something like a "read_uncached()" call...

That would mean that a seq scan or a vacuum wouldn't force useful data
out of cache.
-- 
let name="cbbrowne" and tld="cbbrowne.com" in String.concat "@" [name;tld];;
http://www.ntlug.org/~cbbrowne/linuxxian.html
A VAX is virtually a computer, but not quite.


[Postgresql General]     [Postgresql PHP]     [PHP Users]     [PHP Home]     [PHP on Windows]     [Kernel Newbies]     [PHP Classes]     [PHP Books]     [PHP Databases]     [Yosemite]

  Powered by Linux