QAN MariaDB Example query is trimmed

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1

Hi Team,

We are unable to obtain the whole query because it has been truncated in the QAN DB.

Despite setting “max_query_length=-1” in the pmm-agent configuration, the query is being cut.

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2

Hi @Naresh9999, it can be trimmed on MariaDB side. Please check Performance Schema System Variables - MariaDB Knowledge Base

3

No @nurlan

I am able to see full query of Fingerprint column but only issue with the example tab. We are not able to see the full query of the Example column.

4

@Naresh9999,
Please confirm that you are using the slow query log as the source for PMM. SSH to the machine in question, and run pmm-admin list. Then, check the slow log itself. Look for the query. Ensure that MariaDB is not truncated the query into the slow log.

5

@matthewb @nurlan But how come the Fingerprint column displays the entire query but the Example column displays a truncated query?

6

Fingerprints replaces actual values with placeholders which take 1 symbol when values in real examples might be longer and therefore examples might be longer than fingerprints.

7

@matthewb @nurlan Thanks for the details.
What is the solution for this issue?

8

Increase performance_schema_max_digest_length variable to 4096, and restart MariaDB. Verify that queries in performance_schema.events_statements_summary_by_digest table are no longer being truncated.