| Measurement |
Description |
Measurement
Unit |
Interpretation |
| Query_rate |
The
rate at which queries are sent to the server
|
Queries/sec |
This
is an indicator of server workload. |
| Slow_queries |
The
number of queries that have taken more than the 'long_query_time' for
execution, during the last measurement period |
Number
|
|
| Handler_read_first |
The
number of times the first entry was read from an index during the last
measurement period |
Number
|
If the value of this measure is high, it suggests that the server is
doing a lot of full index scans.
|
| Handler_read_key |
The
number of requests that were received in the last measurement period,
to read a row based on a key |
Number
|
If the value of this measure is high, it indicates that your
queries and tables are properly indexed.
|
| Handler_read_next |
The
number of requests received in the last measurement period, to read
the next row in the key order |
Number
|
This will be incremented if you are querying an index column with a
range constraint. This will also be incremented if you are doing an
index scan.
|
| Handler_read_prev |
The
number of requests received in the last measurement period, to read
the previous row in the key order |
Number
|
This is mainly used to optimize ORDER BY... DESC.
|
| Handler_read_rnd |
The
number of requests received in the last measurement period, to read a
row based on a fixed position |
Number
|
This will be high if you are executing a lot of queries that require sorting
of the result. If the value of ' Handler_read_rnd' is high, then you
probably have a lot of queries that require MySQL to scan whole
tables or you have joins that do not use keys properly.
|
| Handler_read_rnd_next |
The
number of requests received in the last measurement period, to read the
next row in the datafile |
Number
|
This will be high if you are performing a lot of table scans. Generally,
this suggests that your tables are not properly indexed or that your
queries are not written to use the indexes properly.
|