[tcapulusdb knowledge base] Introduction to tcapulusdb engine parameter adjustment

1. Tcaplus Engine parameter adjustment is mostly used for performance tuning and data reorganization , This section mainly enables readers to understand the respective functions of engine parameters , Engine parameter adjustment is essentially a kind of data relocation , The operation of the relocation bill of lading will not be repeated .

2. 

3. 

4. 

5. " Adjust engine parameters ” You can also not move , Keep the original value , then “ modify Shard Distribution ” choice “ Manual ”, In this way, the engine parameters are not changed Shard Data relocation （Shard The total remains unchanged , But adjustable Shard stay Svr The distribution on ）

6. Engine parameter resolution ：bnum=7500000#xmsiz=1000000000#lnum=7300000#xikmsiz=475000000#kfapow=6#kmapow=6#vfapow=6#vmapow=6

   1. bnum,hash Barrel size ,Tcaplus rely on hash Bucket to reach O(1) Access efficiency , here hash The length of the barrel is bnum, Too long will waste , Too small hash More conflicts lead to higher binary tree height , The default configuration is recommended

   2. xmsiz, How many before GB The file is mapped in memory , It is recommended that the default 1GB, If you need more data in memory , It is suggested to expand the capacity horizontally , That is, divide more shard come out

   3. lnum,LRU Number of nodes , This is LRU Third party nodes needed to exchange hot and cold data , The default value is recommended

   4. xikmsiz, In memory key The size of the occupation , In order to make the best of key Put it in memory , Here, some areas are set in the memory to store key, Cannot be stored value, here xmsiz That's the parameter , It's a waste of time , Too small can lead to key Put it in SSD On the disk , Generally, the default value

   5. kfapow,key stay SSD The size of tofu pieces cut on the plate , such as 2^6 = 64B

   6. kmapow, key The size of tofu cut in memory , such as 2^6 = 64B

   7. vfapow,value stay SSD The size of tofu pieces cut on the plate , such as 2^6 = 64B

   8. vmapow, value The size of tofu cut in memory , such as 2^6 = 64B

      there kmapow、vmapow Be sure to design reasonably , It will not lead to the waste of data in memory ,cache High hit rate ,kfapow、vfapow This needs to be reasonable , It leads to waste or multiple disks IO Affect performance

---

For more information, please pay attention to TcaplusDB WeChat official account , In the wind and rain , We've been waiting for you ！

TcaplusDB It's a distributed product of Tencent NoSQL database , The code for storage and scheduling is completely self-developed . With cache + Landing fusion architecture 、PB Levels of storage 、 Millisecond delay 、 Lossless horizontal expansion and complex data structure . At the same time, it has rich ecological environment 、 Easy migration 、 Extremely low operation and maintenance costs and five nine high availability features . Customer coverage game 、 Internet 、 government affairs 、 Finance 、 Manufacturing and the Internet of things .