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https://issues.apache.org/jira/browse/HBASE-29688?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
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Charles Connell updated HBASE-29688:
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Description: Java offers {{VarHandle}} to facilitate fast access to memory,
in place of the {{Unsafe#get*}} and {{Unsafe#put*}} methods. It can be used as
almost a drop-in replacement, and the performance is similar. {{VarHandle}} was
introduced in Java 9. HBase 2.x supports Java 8, so we cannot use {{VarHandle}}
in 2.x releases, but we can prepare to use it in 3.x releases, which target
Java 17. This will eliminate most uses of {{Unsafe}} in HBase. Remaining uses
of {{Unsafe}} are for copying memory regions. There is an alternative available
for that, {{MemorySegment}}, that is available in Java 22 and higher, but we'll
tackle that much later. (was: Java offers {{VarHandle}} to facilitate fast
access to memory, in place of the {{Unsafe#get*}} and {{Unsafe#put*}} methods.
It can be used as almost a drop-in replacement, and the performance is similar.
{{VarHandle}} was introduced in Java 9. HBase 2.x supports Java 8, so we cannot
use {{VarHandle}} in 2.x releases, but we can prepare to use it in 3.x
releases. This will eliminate most uses of {{Unsafe}} in HBase. Remaining uses
of {{Unsafe}} are for copying memory regions. There is an alternative available
for that, {{MemorySegment}}, that is available in Java 22 and higher, but we'll
tackle that much later.)
> Use VarHandle instead of Unsafe where possible in 3.x
> -----------------------------------------------------
>
> Key: HBASE-29688
> URL: https://issues.apache.org/jira/browse/HBASE-29688
> Project: HBase
> Issue Type: Improvement
> Reporter: Charles Connell
> Assignee: Charles Connell
> Priority: Minor
>
> Java offers {{VarHandle}} to facilitate fast access to memory, in place of
> the {{Unsafe#get*}} and {{Unsafe#put*}} methods. It can be used as almost a
> drop-in replacement, and the performance is similar. {{VarHandle}} was
> introduced in Java 9. HBase 2.x supports Java 8, so we cannot use
> {{VarHandle}} in 2.x releases, but we can prepare to use it in 3.x releases,
> which target Java 17. This will eliminate most uses of {{Unsafe}} in HBase.
> Remaining uses of {{Unsafe}} are for copying memory regions. There is an
> alternative available for that, {{MemorySegment}}, that is available in Java
> 22 and higher, but we'll tackle that much later.
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