This shows you the differences between two versions of the page.
| Both sides previous revision Previous revision Next revision | Previous revision | ||
|
admin:optimization:plans:home [2012/02/03 19:38] doc |
admin:optimization:plans:home [2016/06/28 22:38] (current) |
||
|---|---|---|---|
| Line 15: | Line 15: | ||
| ---- | ---- | ||
| - | \\ | + | |
| ==== Overview ==== | ==== Overview ==== | ||
| Line 47: | Line 47: | ||
| The EXPLAIN command can also follow a query in OdxSQL. It will provide a query plan for the query that was just executed. This approach has the advantage of having more statistics about the query; however, generating the query plan before the query is run has the advantage of checking a query before it consumes too many resources. | The EXPLAIN command can also follow a query in OdxSQL. It will provide a query plan for the query that was just executed. This approach has the advantage of having more statistics about the query; however, generating the query plan before the query is run has the advantage of checking a query before it consumes too many resources. | ||
| - | A plan consists of two sections: the Summary and the Details. The Summary section shows the SQL statement, the version of Omnidex, any optimization settings or warnings that affect the query, and even occasional suggestions for optimizing the query. The Details section shows the steps that will be executed to satisfy the query. Steps are executed in the order displayed, and are indented as needed to show loops of instructions. | + | A plan consists of two sections: the Summary and the Details. The Summary section shows the SQL statement, the version of Omnidex, and any optimization warnings or suggestions about the query. The Details section shows the steps that will be executed to satisfy the query. |
| In the simple example above, three columns are retrieved from the INDIVIDUALS table. Since no criteria was provided in a WHERE clause, the details of the plan show that the table is retrieved sequentially and the columns are returned. A simple warning indicates that a sequential scan is taking place, which in this case cannot be avoided. | In the simple example above, three columns are retrieved from the INDIVIDUALS table. Since no criteria was provided in a WHERE clause, the details of the plan show that the table is retrieved sequentially and the columns are returned. A simple warning indicates that a sequential scan is taking place, which in this case cannot be avoided. | ||
| Line 60: | Line 60: | ||
| ====== Additional Resources ====== | ====== Additional Resources ====== | ||
| See also: | See also: | ||
| - | {{page>:admin:indexing:see_also&nofooter&noeditbtn}} | + | {{page>:admin:optimization:see_also&nofooter&noeditbtn}} |
| {{page>:bottom_add&nofooter&noeditbtn}} | {{page>:bottom_add&nofooter&noeditbtn}} | ||