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LogManagerImpl#getEntryFromMemory(long index) 遍历logsInMemory太耗费cpu了 #65

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gumandy opened this issue Mar 26, 2019 · 9 comments
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LogManagerImpl#getEntryFromMemory(long index) 遍历logsInMemory太耗费cpu了 #65

gumandy opened this issue Mar 26, 2019 · 9 comments
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@fengjiachun
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enhancement New feature or request good first issue Good for newcomers
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v1.2.5
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1.2.5

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@gumandy
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gumandy commented Mar 26, 2019

Requires.requireTrue(。。。descLogsInMemory()），descLogsInMemory这个操作每次都跑一下也挺happy的
@killme2008
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Good catch ! 这里确实是一个优化的点，包括是不是将 logsInMemory 改成无锁的数据结构。

@killme2008 killme2008 added enhancement New feature or request good first issue Good for newcomers labels Mar 26, 2019
@fengjiachun
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主要是这里不应该使用 Requires.requireTrue(), 避免无意义的 descLogsInMemory() 即可

@killme2008
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@fengjiachun 不只的，这里我也想过是不是用复合数据结构，再引入一个 concurrent map，这样从 log index -> log entry 的查找速度可以加速。

@killme2008
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也可以考虑是不是用 ConcurrentSkipListMap 来替换，同时支持有序和随机查找的需求，并且可以无锁化。

@gumandy
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gumandy commented Mar 26, 2019

现有这个数据结构，随机删只要移动数组的

@killme2008
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@fengjiachun 我记错了，这里是数组定位查找，并没有随机查找的开销，修改这个 descLogsInMemory 即可。

fengjiachun added a commit that referenced this issue Mar 26, 2019
@fengjiachun
(fix) #65
763ad2b
@fengjiachun
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现有这个数据结构，随机删只要移动数组的

确实这个也应该优化一下

fengjiachun added a commit that referenced this issue Mar 26, 2019
@fengjiachun
(fix) optimize 'truncate log' #65
8a959de
@fengjiachun
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@killme2008 @gumandy 考虑到数组结构对 cpu cache 更友好, 这里还是沿用数组结构，truncatePrefix 时用 subList(0, indexToRemove).clear() 来优化一下，避免不断的移动数组

@fengjiachun fengjiachun added this to To do in v1.2.5 via automation Mar 26, 2019
@fengjiachun fengjiachun added this to the 1.2.5 milestone Mar 26, 2019
@fengjiachun fengjiachun self-assigned this Mar 26, 2019
fengjiachun added a commit that referenced this issue Mar 27, 2019
@fengjiachun
(fix) #65 (fix) #65 (#67)
802310d 
* (fix) #65

* (fix) optimize 'truncate log'  #65

* (fix) typo and expose removeRange method

* (fix) avoid unnecessary array copy

* (fix) add fail status message

* (fix) typo

* (fix) minor fix
@fengjiachun
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没有其他问题先关闭了

v1.2.5 automation moved this from To do to Done Mar 27, 2019
@fengjiachun fengjiachun mentioned this issue Apr 1, 2019
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enhancement New feature or request good first issue Good for newcomers
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@killme2008 @fengjiachun @gumandy