Problem
When using the Bigtable HBase client for Java to interact with your Cloud Bigtable instance, you may observe occasional RuntimeExceptions with the warning message ManagedChannel allocation site in your application log file.
Environment
- Java application running the java-bigtable-hbase library before v1.20.0
Solution
Upgrade your java-bigtable-hbase library to v1.20.0 or above. The issue is now fixed as part of this pull request.
Cause
Prior to v1.20.0, there is an issue that allows the gRPC sessions to remain open unintentionally. When this exception is logged, the Bigtable client is establishing a new gRPC connection/channel with the Bigtable server. As part of this effort, the client library attempted to clean up unused resources, but encountered an unexpected failure when doing so. There is no side effect as a result of these clean-up failures, and so this warning message can be ignored in versions prior to v1.20.0. The warning message will not be logged in v1.20.0 or above since the gRPC sessions are no longer unintentionally held open.