Forums / General / MySQL Runtime Information: Handler_read_rnd_next very high
Martin Burger
Saturday 18 November 2006 5:50:34 am
Hello!
I checked the runtime information of a MySQL instance that hosts databases for Exponential. The variable "Handler_read_rnd_next" is very high (relative to the number of visits): 3 M
The description of phpMyAdmin says: "The number of requests to read the next row in the data file. This 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."
So, why does Exponential cause a lot of table scans? Or, is any index missing?
Regards, Martin
http://www.netbeyond.de/
André R.
Sunday 19 November 2006 4:22:29 am
This depends on what Exponential version you are running.There where some added indexes in the 3.8 and 3.8.4 versions
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Sunday 19 November 2006 7:33:43 am
We are bound to 3.6.11 because we use Debian stable which provides only PHP 4.3.10 as package. Which indexes were added? Can I add them manually for version 3.6.11?
Monday 20 November 2006 12:52:13 am
The indexes that where not 3.8 specific went into 3.6.9:http://pubsvn.ez.no/nextgen/stable/3.6/update/database/mysql/3.6/dbupdate-3.6.8-to-3.6.9.sql
I guess you have added these indexes, so could you make a issue on this ?http://issues.ez.no