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https://issues.apache.org/jira/browse/KYLIN-3601?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16651247#comment-16651247
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huaicui commented on KYLIN-3601:
--------------------------------
We use our kylin for latency test of concurrency ;We have stored 6 segments in
kylin. And found the query performance of muliple segments is less than 1 big
segment;
Every day is 1 segment,like this:
Query multiple days(qpm)
Segment number 1 day 2 days 3 days 4 days 5 days 6 days
1 5246 5030 4982 5407 5463 4951
2 3891 4098 4291 4070 3694 3961
3 4354 3697 3785 3448 3646 3598
4 3977 3443 3096 3103 2934 2963
5 3663 3328 2947 2681 2657 2628
6 3583 3099 2813 2607 2366 2330
use preparedstatement cache: (6 segments)
===============================================================
concurrency qps avg_latency(ms) 50%(ms) 95%(ms) 99%(ms)
70 36.66 2003 1814 2419 10654
100 35.3 2795 2574 3974 8096
150 37.4 3992 3967 4875 5700
> The max connection number generated by the PreparedContextPool is
> inconsistent with the configuration.
> ------------------------------------------------------------------------------------------------------
>
> Key: KYLIN-3601
> URL: https://issues.apache.org/jira/browse/KYLIN-3601
> Project: Kylin
> Issue Type: Bug
> Components: Query Engine
> Affects Versions: v2.5.0
> Reporter: huaicui
> Priority: Major
> Attachments: FirstResponseDistribute.jpg,
> SixthResponseDistribute.jpg, image-2018-09-28-15-14-00-288.png, image.png
>
>
> 因为并发性能不够，使用了magang提供的PrepareStatement方法进行测试。性能有所有提高，但随着测试次数的增加，吞吐率会越来越低而且数据超时也越来越多。经过修改代码在queryAndUpdateCache最后返回前加入日志打印：logger.debug("BorrowedCount:"+preparedContextPool.getBorrowedCount()
> +",DestroyedCount:"+preparedContextPool.getDestroyedCount()
> +",CreatedCount:"+preparedContextPool.getCreatedCount()
> +",ReturnedCount:"+preparedContextPool.getReturnedCount()
> 同时配置文件加入该配置：
> kylin.query.statement-cache-max-num-per-key=200
>
>
> 日志显示，当同一sql并发一段时间后，PreparedContextPool创建了越来越多PrepareStatement，并没有进行阻塞后续来的请求。
> !image-2018-09-28-15-14-00-288.png!
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