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https://issues.apache.org/jira/browse/IGNITE-12042?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16901152#comment-16901152
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Vyacheslav Koptilin edited comment on IGNITE-12042 at 8/6/19 3:10 PM:
----------------------------------------------------------------------
[~xtern]
> Or am I missing something?
Yep, we are calculating total pages. To be more precise:
{{datarowPages}} = {{datarow.size() / pageMem.systemPageSize()}}
{{linkPages + nonEmptyPages }}= {{nonEmptyPages * (8.0 / pageMem.pageSize() +
*1*)}}
{{additionalPages}} = {{256 // one page per bucket}}
So,
*totalPages* < {{datarowPages + linkPages + nonEmptyPages + additionalPages}}
{\{> AFAIK each data page has overhead }}
{{> (see AbstractDataPageIO.MIN_DATA_PAGE_OVERHEAD, fragmented data row
required 8 bytes more on each page)}}
{{> therefore, these calculations for data row are very approximate.}}
That is the reason why we have the multiplier - 1.5
was (Author: slava.koptilin):
[~xtern]
> Or am I missing something?
Yep, we are calculating total pages. To be more precise:
{{datarowPages}} = {{datarow.size() / pageMem.systemPageSize()}}
{{linkPages + nonEmptyPages }}= {{nonEmptyPages * (8.0 / pageMem.pageSize() +
*1*)}}
{{additionalPages}} = 256 // one page per bucket
So,
*totalPages* < {{datarowPages + linkPages + nonEmptyPages + additionalPages}}
{{> AFAIK each data page has overhead }}
{{> (see AbstractDataPageIO.MIN_DATA_PAGE_OVERHEAD, fragmented data row
required 8 bytes more on each page)}}
{{> therefore, these calculations for data row are very approximate.}}
That is the reason why we have the multiplier - 1.5
> Atempt to remove entries from fully populated data region may result in
> IgineOutOfMemoryException
> -------------------------------------------------------------------------------------------------
>
> Key: IGNITE-12042
> URL: https://issues.apache.org/jira/browse/IGNITE-12042
> Project: Ignite
> Issue Type: Bug
> Affects Versions: 2.7
> Reporter: Vyacheslav Koptilin
> Assignee: Vyacheslav Koptilin
> Priority: Major
> Fix For: 2.8
>
> Time Spent: 10m
> Remaining Estimate: 0h
>
> Removing entries from non-persistent data region may require allocating a new
> data page in order to move a tracked page from one bucket of the free-list to
> another one.
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