Paul,
On Wednesday 16 November 2011 at 06:04 Dmitry Yemanov wrote:
Also, some
Windows versions are suspected in giving the file system cache too
high priority thus possibly swapping out the pages of the process
working set, so a largish internal page cache could prove itself to be
a
Hi Vlad,
as the subject says. What's the unit for the resulting values for number
of reads, writes, fetches, marks? Just want to be sure if a particular
result makes sense here. ;-)
Same as for isql's statistics - number of operations. Note, we have no
operations on group of pages, so,
Hi Vlad,
as the subject says. What's the unit for the resulting values for number
of reads, writes, fetches, marks? Just want to be sure if a particular
result makes sense here. ;-)
Same as for isql's statistics - number of operations. Note, we have no
operations on group of pages,
Hi Vlad,
as the subject says. What's the unit for the resulting values for number
of reads, writes, fetches, marks? Just want to be sure if a particular
result makes sense here. ;-)
Same as for isql's statistics - number of operations. Note, we have no
operations on group of pages,
- Original Message -
From: Thomas Steinmaurer t...@iblogmanager.com
To: For discussion among Firebird Developers
firebird-devel@lists.sourceforge.net
Sent: Tuesday, November 15, 2011 12:11 AM
Subject: Re: [Firebird-devel] Trace API - What's the unit for number of (reads
|fetches ...)
In your example we see 7149 physical reads and 214192 times this
pages was referenced by the engine. To read a record engine needs to
access pointer page and (at least one) data page. You have ~100K records
so we can explain ~200K fetches.
Ok, but is there a way then to tell how
On Mon, Nov 14, 2011 at 5:11 PM, Thomas Steinmaurer
t...@iblogmanager.comwrote:
Ok, but is there a way then to tell how many pages have been fetched
from the cache as the number above for fetched is more likely
referenced and not real number of pages fetched from memory?
Pages aren't
Ann,
On Mon, Nov 14, 2011 at 4:40 PM, Thomas Steinmaurer t...@iblogmanager.com
mailto:t...@iblogmanager.com wrote:
So, the numbers I see is number of pages?
For reads and writes. Marks and Fetches are recorded each time a page
is referenced in cache. So if you read 20 records on a
On Mon, Nov 14, 2011 at 5:11 PM, Thomas Steinmaurer t...@iblogmanager.com
mailto:t...@iblogmanager.com wrote:
Ok, but is there a way then to tell how many pages have been fetched
from the cache as the number above for fetched is more likely
referenced and not real number of
It would be also interesting if reads exposed in various places (isql,
monitoring tables, trace api) are pure physical reads from disk and/or
fetched from the OS file system cache.
I guess, it could be also from the file system cache, because I've seen
situations where execution time is
It would be also interesting if reads exposed in various places (isql,
monitoring tables, trace api) are pure physical reads from disk and/or
fetched from the OS file system cache.
I guess, it could be also from the file system cache, because I've seen
situations where execution time is
Vlad,
PS Snapshot (concurrency) transaction guarantees that once read record
could be read again and will be the same. So, in theory, we can just
re-read same data page when looking for next record.
Why in theory?
Because i want to be careful and don't want to make too early
PS Snapshot (concurrency) transaction guarantees that once read
record could be read again and will be the same. So, in theory, we
can just re-read same data page when looking for next record.
Why in theory?
Because i want to be careful and don't want to make too early
15.11.2011 2:11, Thomas Steinmaurer wrote:
I guess the same applies to MON$IO_STATS.MON$PAGE_FETCHES? If so, isn't
comparing MON$PAGE_READS with MON$PAGE_FETCHES a bit misleading if one
wants to check to possibly increase the database page buffers?
I bet you're thinking about the cache hit
14 matches
Mail list logo
