Josh Kupershmidt wrote:
> On Fri, Oct 8, 2010 at 8:14 AM, Mladen Gogala <mladen(dot)gogala(at)vmsinfo(dot)com> wrote:
> > Mladen Gogala wrote:
> >> So, essentially, the process is reading block by block, in a sequence.
> >> What, exactly, does "effective_io_concurrency" mean?
> > To rephrase my question, can anybody tell me where in the code is it used?
> The docs are a bit sparse here :-(
> But it looks to me like effective_io_concurrency only affects bitmap
> heap scans. The setting from effective_io_concurrency gets put into
> "target_prefetch_pages" in ./src/backend/utils/misc/guc.c . But the
> only place which uses that variable is
> The EnterpriseDB docs
> "effective_io_concurrency is only used for Bitmap Heap Scans. For
> normal sequential scans the operating system should handle read-ahead
> internally (On Linux, see the blockdev command, in particular --setra
> and --setfra)."
So, this this also true for community Postgres? Can someone suggest
Bruce Momjian <bruce(at)momjian(dot)us> http://momjian.us
+ It's impossible for everything to be true. +
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