Documentation Home
MySQL 5.7 Reference Manual
Related Documentation Download this Manual
PDF (US Ltr) - 35.4Mb
PDF (A4) - 35.6Mb
PDF (RPM) - 33.8Mb
EPUB - 8.5Mb
HTML Download (TGZ) - 8.3Mb
HTML Download (Zip) - 8.4Mb
HTML Download (RPM) - 7.2Mb
Eclipse Doc Plugin (TGZ) - 9.2Mb
Eclipse Doc Plugin (Zip) - 11.3Mb
Man Pages (TGZ) - 198.4Kb
Man Pages (Zip) - 302.4Kb
Info (Gzip) - 3.2Mb
Info (Zip) - 3.2Mb
Excerpts from this Manual

6.7.1.8 Read Row Probes

The read row probes are triggered at a storage engine level each time a row read operation occurs. These probes are specified within each storage engine (as opposed to the *row-start probes which are in the storage engine interface). These probes can therefore be used to monitor individual storage engine row-level operations and performance. Because these probes are triggered around the storage engine row read interface, they may be hit a significant number of times during a basic query.

read-row-start(database, table, scan_flag)
read-row-done(status)
  • read-row-start: Triggered when a row is read by the storage engine from the specified database and table. The scan_flag is set to 1 (true) when the read is part of a table scan (that is, a sequential read), or 0 (false) when the read is of a specific record.

  • read-row-done: Triggered when a row read operation within a storage engine completes. The status returns 0 on success, or a positive value on failure.


User Comments
Sign Up Login You must be logged in to post a comment.