Some metrics missing for RDS proxy MySql Aurora


We have a RDS proxy in front of an MySQL aurora instance.

Many of the metrics I would expect to see are not showing: DatabaseConnectionsCurrentlySessionPinned, DatabaseConnectionsCurrentlyInTransaction, DatabaseConnectionsCurrentlyBorrowed. These all return missing not 0 for any timeframe.

I can connect to the proxy (using a connection on the proxy) and type BEGIN to open a transaction, and I would expect the DatabaseConnectionsCurrentlyInTransaction metric to be at least 1 until I roll back the transaction or commit it. However the data is still 'missing'.

Any ideas as to how to resolve this?

2 Answers
Accepted Answer

Thank you for reaching out. I understand you are unable to see any data for the below metrics : DatabaseConnectionsCurrentlySessionPinned, DatabaseConnectionsCurrentlyInTransaction, DatabaseConnectionsCurrentlyBorrowed.

The above 3 metrics is a direct result of Dimension set 1, Dimension set 3, Dimension set 4 with the statistic as SUM.

Dimension set 1: ProxyName Dimension set 3: ProxyName, TargetGroup, Target Dimension set 4: ProxyName, TargetGroup, TargetRole

Additionally, Pinning is a situation when RDS Proxy cannot be sure that it is safe to reuse a database connection outside the current session. This usually occurs when the client mutates the session state (variables and configuration parameters that you can change through SET or SELECT statements). In such a case, it keeps the session on the same connection until the session ends.

Typically pinning occurs in the following conditions :

  • session parameters are changed
  • temp tables are created
  • locking functions are called
  • prepared statements are used
  • user-defined variables are declared

I understand you are running query and if the block of code satisfies the above then that session will get pinned.

The above information will provide you with details to triage the issue. Please note this is general guidance only. In order to understand the issue fully, we require details that are non-public information. Please open a support case with AWS using the following link.

As always, Happy Cloud Computing.

answered 3 years ago
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reviewed a month ago
  • Thanks!

    Yes I can find the metrics if I go and find them in cloudwatch metrics, and I can see the values are > 0.

    However my initial question was about the 'metrics' tab in the actual RDS proxy AWS section, that still shows 'no data'. From the above that a) the data is there in cloudwatch metrics and b) its not showing on the RDS proxy page, I suggest this is a bug?


@electric_al I have the same issue with the following metrics not showing in the RDS proxy details page metrics list: DatabaseConnectionsCurrentlyInTransaction DatabaseConnectionsCurrentlySessionPinned DatabaseConnectionsCurrentlyBorrowed ClientConnectionsSetupFailedAuth DatabaseConnectionsSetupFailed QueryDatabaseResponseLatency

I am able to add all of these metrics other than ClientConnectionsSetupFailedAuth to a cloudwatch graph directly using the metrics selection list.

The source of the issue is that the RDS proxy details page - metrics graphs configuration for these 6 metrics are filtered on the target-group and target. I have a case open with AWS support to have the metrics reconfigured for the RDS proxy details page with the filters removed.

answered 2 years ago

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