问题
I want to transfer data from one Cassandra cluster (reached via 192.168.0.200) to another Cassandra cluster (reached via 127.0.0.1). The data is 523 rows but each row is about 1 MB. I am using the COPY FROM and COPY TO command. I get the following error when I issue the COPY TO command:
Error for (8948428671687021382, 9075041744804640605):
OperationTimedOut - errors={
'192.168.0.200': 'Client request timeout. See Session.execute[_async](timeout)'},
last_host=192.168.0.200 (will try again later attempt 1 of 5).
I tried to change the ~/.cassandra/cqlshrc file to:
[connection]
client_timeout = 5000
But this hasn't helped.
回答1:
It's not clear which version of Cassandra you're using here so I'm going to assume 3.0.x
The COPY function is good but not always the best choice (i.e. if you have a lot of data), however for this though you might want to check some of your timeout settings in cassandra
The docs here show a pagetimeout setting too which may help you.
Moving data between two clusters can be done a number of other ways. You could use of any of the following:
- The sstableloader
- One of the drivers like the java driver
- Using spark to copy data from one cluster to another, like in this example
- Using OpsCenter to clone a cluster
- The cassandra bulk loader (I've known a number of people to use this)
Of course #3 and #4 need DSE cassandra but its just to give you an idea. I wasn't sure if you were using Apache Cassandra or Datastax Enterprise Cassandra.
Anyway, hope this helps!
回答2:
You may want to increment the request timeout (default: 10 seconds), not the connect timeout.
Try:
cqlsh --request-timeout=6000
or add:
[connection]
request_timeout = 6000
to your ~/.cassandra/cqlshrc file.
回答3:
Regarding the copy timeout the correct way is to use the PAGETIMEOUT parameter as already pointed.
copy keyspace.table to '/dev/null' WITH PAGETIMEOUT=10000;
Trying to set the --request-timeout=6000 with cqlsh does not help in that situation.
回答4:
Hi besides the following,
1.Check tombstones
In cassandra tombstones degrade the performance of reads and following issue occur OperationTimedOut: errors={'127.0.0.1': 'Client request timeout. See Session.execute_async'}, last_host=127.0.0.1
Note
When we insert data in to the table with null values in columns it creates a tombstones. we need to avoid null inserts inside the table.
There are multiple options available like unset(https://docs.datastax.com/en/latest-csharp-driver-api/html/T_Cassandra_Unset.htm) and ignoreNulls (https://github.com/datastax/spark-cassandra-connector/blob/master/doc/5_saving.md) property in spark.
You can check your table status using the following command
nodetool tablestats keyspace1.tablename
2.Remove Tombstones
If your working on a single node you can remove tombstones by altering your table
ALTER table keyspace1.tablename
WITH gc_grace_seconds = '0';
3.read_request_timeout_in_ms:Configure the value in cassandra.yaml file to increase timeout for a read request
来源：https://stackoverflow.com/questions/39955968/cassandra-cqlsh-operationtimedout-error-client-request-timeout-see-session-exec