[
https://issues.apache.org/jira/browse/BOOKKEEPER-964?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]
Sijie Guo resolved BOOKKEEPER-964.
----------------------------------
Resolution: Fixed
Issue resolved by merging pull request 72
[https://github.com/apache/bookkeeper/pull/72]
{noformat}
commit ecbb053e6e873859507e247cae727f4bc8b9f7fa
Author: Matteo Merli <[email protected]>
AuthorDate: Tue Nov 29 15:17:46 2016 -0800
Commit: Sijie Guo <[email protected]>
CommitDate: Tue Nov 29 15:17:46 2016 -0800
BOOKKEEPER-964: Add concurrent maps and sets for primitive types
In BookKeeper there are many instances of maps and sets that use ledger id
and entry ids as keys or values. JDK concurrent collections have the
overhead
of boxing all the primitive values into objects (eg: long --> Long) that
would
need to be allocated from the heap. In addition to that, JDK map
implementations
are closed hash tables and they will require at least one more allocation
to hold
the linked-list/tree node.
There are already available libraries that offer primitive collections with
zero-allocation, but none of these support concurrent maps/sets.
We have added a handful of specializations, all based on the same
implementation
idea. We have a hash table which is broken down into multiple sections. Each
sections, on its own, is an open hash table with linear probing, protected
by
a stamped lock.
All insertions, lookups and iterations on these collections are allocation
free.
```
ConcurrentLongHashMap: Map<long, Object>
ConcurrentLongHashSet: Set<long>
ConcurrentLongLongHashMap: Map<long, long>
ConcurrentLongLongPairHashMap: Map< Pair<long, long>, Pair<long, long> >
ConcurrentOpenHashMap: Map<Object, Object>
ConcurrentOpenHashSet: Set<Object>
```
Author: Matteo Merli <[email protected]>
Reviewers: Sijie Guo <[email protected]>, Enrico Olivelli
<[email protected]>
Closes #72 from merlimat/bk-collections
{noformat}
> Add concurrent maps and sets for primitive types
> ------------------------------------------------
>
> Key: BOOKKEEPER-964
> URL: https://issues.apache.org/jira/browse/BOOKKEEPER-964
> Project: Bookkeeper
> Issue Type: Improvement
> Reporter: Matteo Merli
> Assignee: Matteo Merli
> Fix For: 4.5.0
>
>
> In BookKeeper there are many instances of maps and sets that use ledger id
> and entry ids as keys or values. JDK concurrent collections have the overhead
> of boxing all the primitive values into objects (eg: long --> Long) that would
> need to be allocated from the heap. In addition to that, JDK map
> implementations
> are closed hash tables and they will require at least one more allocation to
> hold
> the linked-list/tree node.
> There are already available libraries that offer primitive collections with
> zero-allocation, but none of these support concurrent maps/sets.
> We have added a handful of specializations, all based on the same
> implementation
> idea. We have a hash table which is broken down into multiple sections. Each
> sections, on its own, is an open hash table with linear probing, protected by
> a stamped lock.
> All insertions, lookups and iterations on these collections are allocation
> free.
> {noformat}
> ConcurrentLongHashMap: Map<long, Object>
> ConcurrentLongHashSet: Set<long>
> ConcurrentLongLongHashMap: Map<long, long>
> ConcurrentLongLongPairHashMap: Map< Pair<long, long>, Pair<long, long> >
> ConcurrentOpenHashMap: Map<Object, Object>
> ConcurrentOpenHashSet: Set<Object>
> {noformat}
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