MaxScale 24.02 Transaction Performance Monitoring Filter
Note: This module is experimental and must be built from source. The module is deprecated in MaxScale 23.08 and might be removed in a future release.
Overview
The Transaction Performance Monitoring (TPM) filter is a filter module for MaxScale that monitors every SQL statement that passes through the filter. The filter groups a series of SQL statements into a transaction by detecting 'commit' or 'rollback' statements. It logs all committed transactions with necessary information, such as timestamp, client, SQL statements, latency, etc., which can be used later for transaction performance analysis.
Configuration
The configuration block for the TPM filter requires the minimal filter options in it's section within the maxscale.cnf file, stored in /etc/maxscale.cnf.
Filter Options
The TPM filter does not support any filter options currently.
Filter Parameters
The TPM filter accepts a number of optional parameters.
Filename
The name of the output file created for performance logging. The default filename is tpm.log.
Source
The optional source parameter defines an address that is used
to match against the address from which the client connection
to MaxScale originates. Only sessions that originate from this
address will be logged.
User
The optional user parameter defines a user name that is used
to match against the user from which the client connection to
MaxScale originates. Only sessions that are connected using
this username are logged.
Delimiter
The optional delimiter parameter defines a delimiter that is used to
distinguish columns in the log. The default delimiter is :::.
Query_delimiter
The optional query_delimiter defines a delimiter that is used to
distinguish different SQL statements in a transaction.
The default query delimiter is @@@.
Named_pipe
named_pipe is the path to a named pipe, which TPM filter uses to
communicate with 3rd-party applications (e.g., DBSeer).
Logging is enabled when the router receives the character '1' and logging is
disabled when the router receives the character '0' from this named pipe.
The default named pipe is /tmp/tpmfilter and logging is disabled by default.
For example, the following command enables the logging:
Similarly, the following command disables the logging:
Log Output Format
For each transaction, the TPM filter prints its log in the following format:
<timestamp> | <server_name> | <user_name> | <latency of the transaction> | <latencies of individual statements in the transaction> (delimited by 'query_delimiter') | <actual SQL statements>
Examples
Example 1 - Log Transactions for Performance Analysis
You want to log every transaction with its SQL statements and latency for future transaction performance analysis.
Add a filter with the following definition:
After the filter reads the character '1' from its named pipe, the following is an example log that is generated from the above TPM filter with the above configuration:
Note that 3 and 6 are latencies of each transaction in milliseconds, while 0.165 and 0.123 are latencies of the first statement of each transaction in milliseconds.
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