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https://issues.apache.org/jira/browse/ARTEMIS-2216?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16734069#comment-16734069
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ASF GitHub Bot commented on ARTEMIS-2216:
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Github user michaelandrepearce commented on the issue:
https://github.com/apache/activemq-artemis/pull/2484
> em.....Could you please tell us which issues? We need to verify how it
affects our cluster.
The big issue im relating to, which became a night mare for my
organisation, was that under high concurrency (high throughput and low latency
broker setup), the buffers can get mixed up, and was causing index out of
bounds issues.
Fixes were multiple:
https://github.com/apache/activemq-artemis/commit/024db5bd3c1656d265daf60c9e3a362d53b9088b
https://github.com/apache/activemq-artemis/commit/da7fb89037481fb6343c760010d4553ff28ac87e
Im also aware there have been some other concurrency fixes for smaller
issues.
> Use a specific executor for pageSyncTimer
> -----------------------------------------
>
> Key: ARTEMIS-2216
> URL: https://issues.apache.org/jira/browse/ARTEMIS-2216
> Project: ActiveMQ Artemis
> Issue Type: Improvement
> Affects Versions: 2.6.3
> Reporter: Qihong Xu
> Priority: Major
> Attachments: contention_MASTER_global.svg, contention_PR_global.svg,
> contention_PR_single.svg
>
>
> Improving throughput on paging mode is one of our concerns since our cluster
> uses paging a lot.
> We found that pageSyncTimer in PagingStoreImpl shared the same executor with
> pageCursorProvider from thread pool. In heavy load scenario like hundreds of
> consumers receiving messages simultaneously, it became difficult for
> pageSyncTimer to get the executor due to race condition. Therefore page sync
> was delayed and producers suffered low throughput.
>
> To achieve higher performance we assign a specific executor to pageSyncTimer
> to avoid racing. And we run a small-scale test on a single modified broker.
>
> Broker: 4C/8G/500G SSD
> Producer: 200 threads, non-transactional send
> Consumer 200 threads, transactional receive
> Message text size: 100-200 bytes randomly
> AddressFullPolicy: PAGE
>
> Test result：
> | |Only Send TPS|Only Receive TPS|Send&Receive TPS|
> |Original ver|38k|33k|3k/30k|
> |Modified ver|38k|34k|30k/12.5k|
>
> The chart above shows that on modified broker send TPS improves from “poor”
> to “extremely fast”, while receive TPS drops from “extremely fast” to
> “not-bad” under heavy load. Considering consumer systems usually have a long
> processing chain after receiving messages, we don’t need too fast receive
> TPS. Instead, we want to guarantee send TPS to cope with traffic peak and
> lower producer’s delay time. Moreover, send and receive TPS in total raises
> from 33k to about 43k. From all above this trade-off seems beneficial and
> acceptable.
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