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https://issues.apache.org/jira/browse/IGNITE-20895?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Alexey Scherbakov resolved IGNITE-20895.
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Resolution: Duplicate
Duplicates IGNITE-23301
> Optimize hierarchy lock manager
> -------------------------------
>
> Key: IGNITE-20895
> URL: https://issues.apache.org/jira/browse/IGNITE-20895
> Project: Ignite
> Issue Type: Improvement
> Affects Versions: 3.0
> Reporter: Alexey Scherbakov
> Priority: Major
> Labels: ignite-3
> Fix For: 3.0
>
>
> Recently a (not very efficient) parentLockManager [1] was introduced to
> handle hierarchy (coarse-grained) locks.
> Currently it's only purpose is to provide strict serializability during full
> table scans, which happens very rarely.
> It comes at the cost of acquiring additional lock on each update op. IS locks
> are never used at all.
> This should be improved. Possible optimizations:
> # Get rid of hierarchy locks and instead scan the primary index for table
> scan. If I recall correctly, Mysql never uses hierarchy locking.
> # If we are absolutely sure that we need hierarchy locking, replace lock
> queuing for IS,IX locks with counters. This prevents waiting, but is looks ok
> for this kind of locks. Only stronger locks should be allowed to wait.
> [1] org.apache.ignite.internal.tx.impl.HeapLockManager#parentLockManager
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