- 5.7.1 mysqld DTrace Probe Reference
- 5.7.1.1 Connection Probes
- 5.7.1.2 Command Probes
- 5.7.1.3 Query Probes
- 5.7.1.4 Query Parsing Probes
- 5.7.1.5 Query Cache Probes
- 5.7.1.6 Query Execution Probes
- 5.7.1.7 Row-Level Probes
- 5.7.1.8 Read Row Probes
- 5.7.1.9 Index Probes
- 5.7.1.10 Lock Probes
- 5.7.1.11 Filesort Probes
- 5.7.1.12 Statement Probes
- 5.7.1.13 Network Probes
- 5.7.1.14 Keycache 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 specifieddatabaseandtable. Thescan_flagis 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— triggerd when a row read operation within a storage engine completes. Thestatusreturns 0 on success, or a positive value on failure.
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