June 18, 2010 in Classic self-hosted technical help
What causes Handler_read_rnd_next to be so high? I am using Xcache with MySQL.
Handler_read_rnd_next 259 M
Handler_read_rnd 1,611 k
Created_tmp_disk_tables 108 k
Does high Handler_read_rnd_next 259 M indicates indexes are not properly used or is something is wrong at my end?
did you delve more into this?
it's just a counter for when next row in a table is read, it doesn't necessarily mean lack of indexes as per the definition from http://dev.mysql.com...r_read_rnd_next as it could also be due to some queries which mysql query optimizer deems isn't suited to using an index
The number of requests to read the next row in the data file. This value is high if you are doing a lot of table scans. Generally this suggests that your tables are not properly indexed or that your queries are not written to take advantage of the indexes you have.
mysqladmin ext | grep Handler_read_rnd_next
| Handler_read_rnd_next | 651021183809 |
Yea I didn't worry about it since I have zero slow queries (2 seconds) in my logs. Also, the no indexes queries all have "query time = 0". I was just curious after seeing red for Handler_read_rnd and Handler_read_rnd_next in PHPmyAdmin status page.
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