Sharding and multiple databases

Community Support
1

Hello. I don’t understand how the “numHistoryShards” configuration works.

E.g:

persistence:
  defaultStore: mysql
  visibilityStore: mysql
  numHistoryShards: 5
  datastores:
    mysql-default:
      sql:
         ....

How can I setup multiple db for it?
I found example for cadence, but this is not suitable for temporal.io.

persistence:
  ...
  datastores:
    datastore1:
      sql:
        pluginName: "mysql"            -- name of the go sql plugin
        connectProtocol: "tcp"         -- connection protocol, tcp or anything that SQL Data Source Name accepts
        maxConnLifetime: "1h"          -- max connection lifetime before it is discarded (optional)
        useMultipleDatabases: true     -- this enabled the multiple SQL databases as sharded SQL cluster
        nShards: 4                     -- the number of shards -- in this mode, it needs to be greater than one and equalt to the length of multipleDatabasesConfig
        multipleDatabasesConfig:       -- each entry will represent a shard of the cluster 
        - user: "root"
          password: "cadence"
          connectAddr: "127.0.0.1:3306"
          databaseName: "cadence0"
        - user: "root"
          password: "cadence"
          connectAddr: "127.0.0.1:3306"
          databaseName: "cadence1"
        - user: "root"
          password: "cadence"
          connectAddr: "127.0.0.1:3306"
          databaseName: "cadence2"
        - user: "root"
          password: "cadence"
          connectAddr: "127.0.0.1:3306"
          databaseName: "cadence3"
2

I don’t understand how the “numHistoryShards” configuration works

This blog post has great info on numHistoryShards.

How can I setup multiple db for it?

I believe this is not the use case for numHistoryShards. Can you explain your use case more please?

3

Temporal doesn’t support multi-db sharding.