That's probably due to page fragmentation: TotalUsedPages shows pages that are not *completely* free. Looks like there's no direct metric responsible for this, but I discovered the following workaround: there exists a metric called "PagesFillFactor". It is computed as follows: (TotalAllocatedPages - FreeSpaceInUsedPages) / TotalAllocatedPages . The problem is that it does not take fully empty pages into account. So we can try to combine several metrics to do the correct calculation: TotalUsedPages - (TotalAllocatedPages - PagesFillFactor * TotalAllocatedPages)
On Sun, Sep 18, 2022 at 4:29 PM 38797715 <[email protected]> wrote: > I've checked TotalUsedPages in ignite.dataRegionMetrics(), it is found > that the logic of this metric is consistent with OffheapUsedSize, that is, > the value will not be updated after data deletion. > 在 2022/9/18 19:42, Alexander Polovtcev 写道: > > Hello, you can check out "TotalUsedPages" and "TotalUsedSize" metrics that > can be found in the Data Region metrics. However, please keep in mind that > this does not take page fragmentation into account. > > On Sat, Sep 17, 2022 at 2:35 PM 38797715 <[email protected]> wrote: > >> Hi team, >> >> We found that if the delete operation is executed, the memory space >> corresponding to the data will not be released, and this space will be >> reused later. >> >> Therefore, metrics such as OffheapUsedSize will become inaccurate. >> >> So, how to calculate the exact amount of memory occupied by data in a >> cache or a dataregion? >> > > > -- > With regards, > Aleksandr Polovtcev > > -- With regards, Aleksandr Polovtcev
