The PctBloatUsedPages and PctBloatReservedPages columns give an estimate of how many more pages than the minimum the table is using and reserving, respectively. These values indicate how beneficial it may be for you to run reorg rebuild on the table.
ExtentUtil is the ratio of the number of pages that are actually being used against the number of pages that are reserved for the object. Values closer to 100 indicate that most of the pages in the extents reserved for the object are currently used. The synopsis of the measurements are:
|
PctBloatUsedPages Value |
PctBloatReservedPages Value |
Interpretation |
|---|---|---|
|
Close to 0, low value |
Close to 0, low value |
Indicates the table is well compacted, and all allocated pages and allocation units are used completely. ExtentUtil should be close to 1.0 |
|
Close to 0, low value |
Not close to 0, high value |
Indicates the used pages are well compacted, but the table’s extents are under-utilized, and there is a large degree of interpage fragmentation, possibly due to large-scale deletions or empty pages. The unusedpgcnt in systabstats is probably also high. The high value of PctBloatReservedPages suggests that ExtentUtil to is probably much less than 1.0. You can probably resolve most issues by running reorg rebuild. |
|
Not close to 0, high value |
Close to 0, low value |
Indicates a large degree of intrapage fragmentation, but a smaller degree of inter-page fragmentation. Because the extent utilization is probably high, ExtentUtil value should be close to 1.0. Running reorg compact may help resolve these issues. |
|
Not close to 0, high value |
Not close to 0, high value |
A high value for PctBloatUsedPages indicates a large degree of intrapage fragmentation, where data rows in used pages are not fully compacted (the used pages contain most of the free space). Because interpage and intrapage fragmentation may cause he high value of PctBloatReservedPages, the value of Extent_Util may still be less than 1.0. Running reorg compact and reorg rebuild may resolve these issues. |