Re: sysmaster question
Jack,
What is your table definition (dbschema -d xx -t yy -ss) ?
Frank
On 1/25/07, Jack Parker <jack.parker4@verizon.net> wrote:
>
> Yes, it is in one chunk.
>
> Here is the table info I gather:
>
> === Most Physically Active Tables ===
>
>
> Table: cdi:message Created: 01/18/2007 Size: 0.35 GB
> Pagesize: 2048 Allocated: 186376 Used: 185935 Data:
> 16889
> Pgs Free: 441 0.0024%
> Rowsize: 170 Columns: 5 Keys: 0
> 1st Ext: 8 Next Ext: 16
>
> Other info from Flags:
> Page level locking
>
> Percent of entire engine activity:
> Isam Ops: 0.29% Buffer Ops: 1.09% Page Ops: 88.76%
>
> Rows according to SMI: 185778 Rows according to Stats 185778
>
> Chunk: 2 dbspace: dbsp1 file: /opt/informix/dev/dbsp1
> Reads: 18364082 Writes: 20129981 PgReads: 3560744 PgWrites:
> 5811620
> Pagesize: 2048
> Avg Rows/Page: 2 Avg Freeptr: 1667 Avg Empty Bytes: 367
> Avg Extent size: 31062 Extents this chk: 6
>
> Number of extents: 6
>
> Pages:
> Room for rows: 1
> Blob semi-full: 1
> Idx/Bitmap: 47
> Blob Full: 97088
> Full: 16888
> Blob Very Full: 71910
>
> Locks Mode: Page
> Requests: 9307658 Waits: 0 Deadlocks: 0 Lock Time outs: 0
>
> Total Activity:
> Sequential Scans: 3
> Isam Reads: 216838 Writes: 3426054 Rewrites: 0 Deletes: 0
> Buffer Reads: 19749173 Writes: 17061814
> Page Reads: 4246956 Writes: 3443422
> Buffer/Isam Reads: 91.08 Buffer/Isam Writes: 4.98
> Page/Isam Reads: 19.59 Page/Isam Writes: 1.01
>
>
> -----Original Message-----
> From: FRANK [mailto:yunyaoqu@gmail.com]
> Sent: Thursday, January 25, 2007 4:16 PM
> To: Jack Parker
> Cc: Informix-List@Iiug. Org
> Subject: Re: sysmaster question
>
>
> Sorry, in one chunk. Frank
>
>
> On 1/25/07, FRANK <yunyaoqu@gmail.com> wrote:
> HI, Jack,
>
> Is this table fragmented to more than one chunk?
>
> Frank
>
>
>
>
> On 1/25/07, Jack Parker < jack.parker4@verizon.net> wrote:
>
> poking about.
>
> I have a table, in a single dbspace, in a single chunk. (Cooked).
>
> According to sysptprof, there have been 4.2 million page reads against the
> table.
>
> According to syschkio, there have been 3.6 million pages read from the
> chunk.
>
> Obviously this is a discrepancy, how is it getting resolved? A request is
> made to disk to read a page, and the page has already been read? Then why
> doesn't it count in bufreads?
>
> This particular table accounts for 88% of my i/o against this disk, so add
> another 400K or so page reads to the 4.2 million number.
>
> Page writes seem to be more consistent with what I'd expect.
>
> cheeers
> j.
>
> _______________________________________________
> Informix-list mailing list
> Informix-list@iiug.org
> http://www.iiug.org/mailman/listinfo/informix-list
>
>