Informix question

Posted in 2011

CHUAN LU — Tue, 13 Sep 2011 06:38:03 — source: IIUG Forums & Mailing Lists

Hi, I have two confused question. 1 When a update SQL will update totally 3 pages in bufferpool? How many mutex IDS will allocate for this thread in the buffer-head entry in the buffer table? 2. What the temporary sbspace will be used for? thanks for your time.

↪ replying to CHUAN LU

Art Kagel — Tue, 13 Sep 2011 12:37:27 — source: IIUG Forums & Mailing Lists

1. No idea, don't care. 2. It is used for Enterprise Replication mostly. Art Art S. Kagel Advanced DataTools (www.advancedatatools.com) Blog: http://informix-myview.blogspot.com/ Disclaimer: Please keep in mind that my own opinions are my own opinions and do not reflect on my employer, Advanced DataTools, the IIUG, nor any other organization with which I am associated either explicitly, implicitly, or by inference. Neither do those opinions reflect those of other individuals affiliated with any entity with which I am affiliated nor those of the entities themselves. On Tue, Sep 13, 2011 at 2:38 AM, CHUAN LU <luchuan@cn.ibm.com> wrote: > Hi, > I have two confused question. > > 1 When a update SQL will update totally 3 pages in bufferpool? How many > mutex > IDS will allocate for this thread in the buffer-head entry in the buffer > table? > > 2. What the temporary sbspace will be used for? > > thanks for your time. > > > > ******************************************************************************* > Forum Note: Use "Reply" to post a response in the discussion forum. > > --90e6ba21219bcf72c104acd1e769

↪ replying to CHUAN LU

JACQUES RENAUT — Wed, 14 Sep 2011 15:53:06 — source: IIUG Forums & Mailing Lists

Original Post: Hi, I have two confused question. 1 When a update SQL will update totally 3 pages in bufferpool? How many mutex IDS will allocate for this thread in the buffer-head entry in the buffer table? 2. What the temporary sbspace will be used for? thanks for your time. Response: 1) Well the thread that is doing the SQL update will not allocate any mutex for the buffer-header entries. Those mutex are allocated up front at engine initialization time, and there would be 1 mutex that is part of the buffer header, and each buffer in your buffer pool has a header. So you'd have at least as many mutexes as buffers in your buffer pool. Jacques Renaut IBM Informix Advanced Support APD Team

Glossary

sbspace