Solve connection leak issue in S3 backup remote delete on versioned buckets #637
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…ectAttributes() instead of s3.GetObject() to retrieve the object's version
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I'm experiencing a connection leak issue on clickhouse-backup where the no. of open connections in the container grow by the thousands each time a 'remote delete' command on s3 is being executed. After a few days, the node would exhaust the TCP memory and drop almost all new TCP connections to it.
Clickhouse-backup version is
altinity/clickhouse-backup:2.1.3.I'm running Clickhouse on EKS with Clickhouse operator, EKS AMI for arm64 1.25.7-20230406 with linux kernel 5.10.
I noticed that the number of created connections is roughly equal to the number of objects being deleted for that shard/day. My backups are uploaded to a versioned S3 bucket.
I believe the bug is in getObjectVersion(): s3.GetObject() actually retrieves the object's body, which create a new connection until you close it.
Use s3.GetObjectAttributes() (which is also cheaper than s3.GetObject) to retrieve the object's version.
/cc @Slach who kindly assisted in troubleshooting!