Informix - Problem description
Problem IT28075 | Status: Closed |
WITH MAX_FILL_DATA_PAGES PAGES MIGHT FOREVER OFFER ROOM NOT SATISFYING ANY NEW ROW, POTENTIALLY CAUSING LONG CHECKPOINT BLOCKS | |
product: | |
INFORMIX SERVER / 5725A3900 / C10 - IDS 12.10 | |
Problem description: | |
With variable row length and MAX_FILL_DATA_PAGES 1, a page would be marked full if either it's 90% full or, with small enough average space occupied by those rows already existing on it, no more such row would fit onto it. So with average row size below 10% page space, more than 90% fill level would still not be considered full and page would be eligible and considered for new inserts. The gap that's left here is with average row lengths larger than 10% of a page's space and remaining free space between these two. If (new) rows tend to be similarly long, not too far from average row lengths, such page could often be considered for an insert, never be used, but still also never be marked full. With many such pages this could lead to long critical sections, often surfacing as long lasting (and blocking) checkpoints. Beyond extensive bitmap searches, an even much larger number of data pages could be looked at in vain over and over again. | |
Problem Summary: | |
**************************************************************** * USERS AFFECTED: * * Users of IDS prior to 12.10.xC13. * **************************************************************** * PROBLEM DESCRIPTION: * * With variable row length and MAX_FILL_DATA_PAGES pages might * * forever offer room that never satisfies any new row, * * potentially causing long checkpoint blocks. * **************************************************************** * RECOMMENDATION: * **************************************************************** | |
Local Fix: | |
Turn off MAX_FILL_DATA_PAGES | |
Solution | |
Workaround | |
not known / see Local fix | |
Timestamps | |
Date - problem reported : Date - problem closed : Date - last modified : | 12.02.2019 04.10.2019 04.10.2019 |
Problem solved at the following versions (IBM BugInfos) | |
12.10.xC13 | |
Problem solved according to the fixlist(s) of the following version(s) |