[teiid-issues] [JBoss JIRA] Commented: (TEIID-1750) Memory handling improvements

[Steven Hawkins (JIRA)]

    [ https://issues.jboss.org/browse/TEIID-1750?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=12629689#comment-12629689 ] 

Steven Hawkins commented on TEIID-1750:
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Changed the buffermanager to only be concerned with the memory state.  Changed the buffering algorithm to be a tiered lru, which significantly reduces reads/writes when accessing table structures.  the old lru/mru/working set model was specifically designed for tuplebuffers which have a linear insertion and forward iteration model.  there will still need to be some tuning made to better support tuplebuffers.

tuplebuffers/tables no longer directly hold managedbatches, which reduces the overall memory footprint.  This also helps effectively limit the softreference population.

put in a rough cut of a block storage scheme.  this is likely to be further refined.  the code should naturally allow for off-heap direct memory buffers to be used for large vm scenarios.

> Memory handling improvements
> ----------------------------
>
>                 Key: TEIID-1750
>                 URL: https://issues.jboss.org/browse/TEIID-1750
>             Project: Teiid
>          Issue Type: Quality Risk
>          Components: Query Engine
>    Affects Versions: 7.0
>            Reporter: Steven Hawkins
>            Assignee: Steven Hawkins
>             Fix For: 7.6
>
>
> The buffermanager will create softreferences for batches that prefer memory, but does not track the memory as held once the value has been passivated.
> Also small lobs, such as xml values created via sqlxml, should be inlined into results for greater performance - and so that they can be paged out by the buffermanager rather than being held by a lobmanager.

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