RE: sysmaster question

Posted in 2007

Jack Parker — Thu, 25 Jan 2007 16:42:07 -0500 — source: Usenet: comp.databases.informix

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