Re: BTSCANNER defaults

Excellent. Thanks for the info Mark. Do you know where I can find the documentation for this new feature? A search of the 10.0 Informix Center doesn't produce anything interesting. Andrew ----- Original Message ----- From: Mark Jamison To: Andrew Ford ; informix-list@iiug.org Sent: Tuesday, December 05, 2006 1:00 PM Subject: Re: BTSCANNER defaults >Do you know of any guidelines as to when an ALICE scan would be preferred >over a leaf or range scan? Sure. ALICE will be preferred over everything. It is more efficient that leaf or range scans. It is new functionality though, so there may be bumps along the way. Honestly I would be suggest starting ALICE at 3, and then use onstat -C alice to see how efficiently the BTSCANNER threads are working. Here is an example of an onstat -C alice from a test system I have (informix) /usr/informix > onstat -C alice IBM Informix Dynamic Server Version 10.00.FC5W5 -- On-Line -- Up 1 days 03:40:24 -- 245148 Kbytes Btree Cleaner Info ALICE Cleaning Statistics ========================= System wide ALICE mode 4 Partnum Mode BM_Sz Used_Pg Examined Dirty_Pg # I/O Found Eff 0x0010001b 4 64 15 0 0 0 0 0.0 % 0x00400008 4 64 9 0 0 0 0 0.0 % 0x00400008 4 64 9 0 0 0 0 0.0 % 0x00400009 4 64 18 0 0 0 0 0.0 % 0x00400009 4 64 18 0 0 0 0 0.0 % 0x0040000a 4 64 25 0 0 0 0 0.0 % 0x0040000a 4 64 25 0 0 0 0 0.0 % 0x0040000b 4 64 11 0 0 0 0 0.0 % 0x0040000b 4 64 11 0 0 0 0 0.0 % 0x00400012 4 64 5 0 0 0 0 0.0 % 0x00400012 4 64 5 0 0 0 0 0.0 % 0x00400012 4 64 5 0 0 0 0 0.0 % 0x00400016 4 64 4 0 0 0 0 0.0 % 0x00400016 4 64 4 0 0 0 0 0.0 % 0x0040001f 4 64 15 15 2 2 1 50.0 % 0x00400020 4 64 3 0 0 0 0 0.0 % 0x00400034 4 64 4 0 0 0 0 0.0 % 0x00400034 4 64 4 0 0 0 0 0.0 % 0x00400043 4 64 80 0 0 0 0 0.0 % 0x00400045 4 64 71 71 19 17 6 35.3 % I've set ALICE to 4 on this particular box.