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https://issues.apache.org/jira/browse/IGNITE-9171?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16728729#comment-16728729
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Vladimir Ozerov commented on IGNITE-9171:
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[~tledkov-gridgain], I have two comments at the moment:
# Can we simplify or extract connection management into a separate ticket with
tests showing why the change is needed? At the moment, as we decided to remove
lazy threads, it is not obvious why all these changes are needed
#
{{IgniteQueryTableLockAndConnectionPoolLazyModeOnTest.testSingleNodeWithParallelismTablesLockQueryAndDDLMultithreaded}}
fails with {{ConcurrentModificationException}}. It seems that we cannot rely
on H2's {{Session.getLocks}} as it is not thread safe, are we?
> Use lazy mode with results pre-fetch
> ------------------------------------
>
> Key: IGNITE-9171
> URL: https://issues.apache.org/jira/browse/IGNITE-9171
> Project: Ignite
> Issue Type: Task
> Components: sql
> Affects Versions: 2.6
> Reporter: Taras Ledkov
> Assignee: Taras Ledkov
> Priority: Blocker
> Labels: sql-stability
> Fix For: 2.8
>
>
> Current implementation of the {{lazy}} mode always starts separate thread for
> {{MapQueryLazyWorker}}. It causes excessive overhead for requests that
> produces small results set.
> We have to begin execute query at the {{QUERY_POOL}} thread pool and fetch
> first page of the results. In case results set is bigger than one page
> {{MapQueryLazyWorker}} is started and link with {{MapNodeResults}} to handle
> next pages lazy.
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