Light Scans and Light Appends (Light Scans/Appends)

Has anyone figured how to capture this information. Can you see it occur during an HPL Load? I've entered the commands: onstat -g lap and onstat -g lscI do not getting any information except the headings...is it some OS Environment or Informix Configuration Variable that needs to be turned on? I saw a posting about LIGHT_SCANS=FORCED ...yet I could not decipher where this is to be set? Thanks, Cheryl L. Kendricks H.E.B. Grocery, Lead DBA Analyst San Antonio, TX ....People..Peopling It to Death... the Life of a PeopleSoft DBA! email: kcheryl@notes.heb.com .....sending again...boy EMAIL SOFTWARE can be a ....sometimes

Cheryl, I'm by no means an expert, so please take my advice with a grain of salt. I have been told that you get light scans if some very specific conditions are met (and I have observed this myself). The first is that you have to be selecting/appending more rows than will fit in the buffers. The second is that you must be doing so in "dirty read" mode, or if your database is non-logging, the table must be locked in share mode, and there is an environment variable LIGHT_SCANS that must be set to FORCE (please note the capital letters, and the "S" on LIGHT_SCANS... that took me 2 hours once to figure out). That said, I don't believe that HPL will show light scans or light appends. I'll be honest; I have no idea why that is, but I've never seen those on an HPL load. Where I've been most successful is with large queries using PDQ. By doing so, I have gotten much better performance than I would have if I had not been doing the light scans. HTH. -- Dan Michaelis Database Administrator dan@kax.com In article <7vdf42$n9m$1@news.xmission.com>, KENDRICKS.CHERYL@heb.com wrote: > > > Has anyone figured how to capture this information. Can you see it occur > during an HPL Load? I've entered the commands: > onstat -g lap and onstat -g lsc> I do not getting any information except the headings...is it some OS > Environment or Informix Configuration Variable that needs to be turned on? > I saw a posting about LIGHT_SCANS=FORCED ...yet I could not decipher where > this is to be set? > > Thanks, > Cheryl L. Kendricks > H.E.B. Grocery, Lead DBA Analyst > San Antonio, TX > ....People..Peopling It to Death... the Life of a PeopleSoft DBA! > email: kcheryl@notes.heb.com > .....sending again...boy EMAIL SOFTWARE can be a ....sometimes > Sent via Deja.com http://www.deja.com/ Before you buy.