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/Missing Aurora wait event reference/

Missing Aurora wait event reference

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I was look on performance_schema for a specific database and i struggle to find any information inside the documentation for the specific wait synch/cond/sql/FILE_AS_TABLE::cond_request

Does somebody can explain me what it is ?

Thanks in advance, Alexis

asked 15 days ago47 views
1 Answers
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Hi Alxsbn,

I believe you queried a performance_schema for a specific database and received an output “synch/cond/sql/FILE_AS_TABLE::cond_request”, now you need more information about the output.

FILE_AS_TABLE is the MySQL feature to locate a file into InnoDB table. We tend to see FILE_AS_TABLE if queries on the database are using a lot of temporary tables, or a large number of tables are being accessed simultaneously by either read or write operations. File definitions are cached in the table_definition_cache. The table_definition_cache is the number of table definitions (from .frm files) that can be stored in the definition cache.

FILE_AS_TABLE has to do with the creation of tmp files. A tmp file is created when we make temporary tables on our database. Generally, if you see high waiting related to FILE_AS_TABLE, it is a good indicator that you have a large number of temporary tables. In your particular case it is likely that the innodb_file_per_table tmp file is in use. If you wish to know more about File-Per-Table, you can read about it here: [1].

[1] https://dev.mysql.com/doc/refman/8.0/en/innodb-file-per-table-tablespaces.html

answered 14 days ago
  • Hi @Lwazi and thanks for your anwser. I fetch this event from performance_schema.events_waits_summary_by_thread_by_event_name It was the #1 event on sum_event_wait, and didn't find anything on it (i already read doc about FILE_AS_TABLE but not the cond_request)

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