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| author | version | line-number | content |
|---|---|---|---|
| 1 | get命令本质是调用了lookupKeyRead这个底层方法， | ||
| 2 | lookupKeyRead方法如下： | ||
| 3 | |||
| 4 | {{plantuml}} | ||
| 5 | @startuml | ||
| 6 | start | ||
| 7 | |||
| 8 | |||
| 9 | : lookupKeyReadWithFlags; | ||
| 10 | |||
| 11 | |||
| 12 | end | ||
| 13 | @enduml | ||
| 14 | {{/plantuml}} | ||
| 15 | |||
| 16 | |||
| 17 | lookupKeyReadWithFlags方法如下： | ||
| 18 | |||
| 19 | {{plantuml}} | ||
| 20 | @startuml | ||
| 21 | start | ||
| 22 | |||
| 23 | if(调用expireIfNeeded方法判断key是否过期) | ||
| 24 | note left | ||
| 25 | 返回1代表已经过期 | ||
| 26 | endnote | ||
| 27 | then(1) | ||
| 28 | if(当前环境为主节点)then(yes) | ||
| 29 | :返回null; | ||
| 30 | stop | ||
| 31 | endif | ||
| 32 | |||
| 33 | if(当前环境为从节点，并且命令为读的时候，那说明key过期是安全的)then(yes) | ||
| 34 | :返回null; | ||
| 35 | stop | ||
| 36 | endif | ||
| 37 | endif | ||
| 38 | |||
| 39 | :调用lookupKey方法，查询value的值; | ||
| 40 | if(返回值为空)then(yes) | ||
| 41 | :缓存命中+1; | ||
| 42 | else(no) | ||
| 43 | :缓存非命中+1; | ||
| 44 | endif | ||
| 45 | |||
| 46 | :返回查询的结果; | ||
| 47 | |||
| 48 | end | ||
| 49 | @enduml | ||
| 50 | {{/plantuml}} |