问题
I see this error continuously in the debug.log in cassandra,
WARN [SharedPool-Worker-2] 2018-05-16 08:33:48,585 BatchStatement.java:287 - Batch of prepared statements for [test, test1] is of size 6419, exceeding specified threshold of 5120 by 1299.
In this
where,
6419 - Input payload size (Batch)
5120 - Threshold size
1299 - Byte size above threshold value
so as per this ticket in Cassandra, https://github.com/krasserm/akka-persistence-cassandra/issues/33 I see that it is due to the increase in input payload size so I Increased the commitlog_segment_size_in_mb in cassandra.yml to 60mb and we are not facing this warning anymore.
Is this Warning harmful? Increasing the commitlog_segment_size_in_mb will it affect anything in performance?
回答1:
This is not related to the commit log size directly, and I wonder why its change lead to disappearing of the warning...
The batch size threshold is controlled by batch_size_warn_threshold_in_kb parameter that is default to 5kb (5120 bytes).
You can increase this parameter to higher value, but you really need to have good reason for using batches - it would be nice to understand the context of their usage...
回答2:
commit_log_segment_size_in_mb represents your block size for commit log archiving or point-in-time backup. These are only active if you have configured archive_command or restore_command in your commitlog_archiving.properties file. Default size is 32mb.
As per Expert Apache Cassandra Administration book:
you must ensure that value of commitlog_segment_size_in_mb must be twice the value of max_mutation_size_in_kb.
you can take reference of this:
Mutation of 17076203 bytes is too large for the maxiumum size of 16777216
来源：https://stackoverflow.com/questions/50385262/cassandra-batch-prepared-statement-size-warning