Persistence jdbc journal batch write timing

nur · June 21, 2021, 6:19am

Hi,

The documentation says internally persistence journal writes are batched with a maximum defined by batchSize. I can’t seem to find the documentation on how long the jdbc client will wait for the batch to be filled until it proceeds with the db write. Can somebody point me to what config defines how long the jdbc client will wait for a batch to be filled before it proceeds with a journal write?

patriknw · June 22, 2021, 5:30pm

Where is that documentation?

There is no such batching to my knowledge, unless using the persistAsync methods. I would recommend against that.

You can add batching in your actor behavior and store more than one event at a time in that way.

nur · June 23, 2021, 12:58pm

I can’t find a documentation for the latest akka version. This is the closest one to mention about batch writes. I’m not sure if the persist calls in akka type call this internally. persistence-journals.html

In the journal jdbc config we have configs for batch write such as batchSize and parallelism.

https://github.com/akka/akka-persistence-jdbc/blob/master/core/src/main/resources/reference.conf

nur · June 24, 2021, 6:28am

@patriknw do you know where these configs are used?

github.com

akka/akka-persistence-jdbc/blob/v4.0.0/core/src/main/resources/reference.conf#L138-L147

    
      
          # The size of the buffer used when queueing up events for batch writing. This number must be bigger then the number
          # of events that may be written concurrently. In other words this number must be bigger than the number of persistent
          # actors that are actively peristing at the same time.
          bufferSize = 1000
          # The maximum size of the batches in which journal rows will be inserted
          batchSize = 400
          # The maximum size of the batches in which journal rows will be read when recovering
          replayBatchSize = 400
          # The maximum number of batch-inserts that may be running concurrently
          parallelism = 8

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Persistence jdbc journal batch write timing

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