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https://issues.apache.org/jira/browse/IGNITE-12510?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=17150642#comment-17150642
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Dmitriy Shirchenko edited comment on IGNITE-12510 at 7/3/20, 12:11 AM:
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Can someone comment on how large of entries will cause eviction to fail? We see
this error on binary blobs of 400MB so wonder if we are hitting this issue.
Edit: I guess I can answer my own question as it would be 5000*page_size. I
guess we can work around this by increasing our page size if we want to support
blobs that big. Still hoping for a better solution.
was (Author: shirchen):
Can someone comment on how large of entries will cause eviction to fail? We see
this error on binary blobs of 400MB so wonder if we are hitting this issue.
> In-memory page eviction may fail in case very large entries are stored in the
> cache
> -----------------------------------------------------------------------------------
>
> Key: IGNITE-12510
> URL: https://issues.apache.org/jira/browse/IGNITE-12510
> Project: Ignite
> Issue Type: Bug
> Affects Versions: 2.7.6
> Reporter: Ivan Rakov
> Priority: Major
> Labels: newbie
>
> In-memory page eviction (both DataPageEvictionMode#RANDOM_LRU and
> DataPageEvictionMode#RANDOM_2_LRU) has limited number of attempts to choose
> candidate page for data removal:
> {code:java}
> if (sampleSpinCnt > SAMPLE_SPIN_LIMIT) { // 5000
> LT.warn(log, "Too many attempts to choose data page: " +
> SAMPLE_SPIN_LIMIT);
> return;
> }
> {code}
> Large data entries are stored in several data pages which are sequentially
> linked to each other. Only "head" pages are suitable as candidates for
> eviction, because the whole entry is available only from "head" page (list of
> pages is singly linked; there are no reverse links from tail to head).
> The problem is that if we put very large entries to evictable cache (e.g.
> each entry needs more than 5000 pages to be stored), there are too few head
> pages and "Too many attempts to choose data page" error is likely to show up.
> We need to perform something like full scan if we failed to find a head page
> in SAMPLE_SPIN_LIMIT attempts instead of just failing node with error.
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