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select sum(val) from numbers;

Notę that any alphabetic values in the result set are turned into 0 by the cali to CAST (). When

using functions such as AVG () that depend on the number of rows in the result set, include WHERE

clauses to filter out any non-numeric values.

•    If the innoDBcolumn you use as a key can be longer than 250 bytes, hash it to a value that is less

than 250 bytes.

•    To use an existing table with the memcachedinterface, define an entry for it in the innodb_memcache. containerstable. To make that the table the default for all requests relayed

through memcached, specify the value default in the name column, then restart the MySQL server

to make that change take effect. If you are using multiple tables for different classes

of memcached

data, set up multiple entries in the innodb_memcache. containerstable with name values of your

choosing, then issue a memcachedrequest of the form get 00name or set 00name withinthe

application to switch the table used for subsequent requests through the

memcachedAPI.

For an example of using a table other than the predefined test .demo_testtable, see

Example 14.5, “Specifying the Table and Column Mapping for an InnoDB + memcached Application".

For the required layout and meaning of the columns in such a table, see Section

14.2.9.7, “Internals

of the InnoDBmemcached Plugin".

•To use multiple MySQL column values with memcachedkey/value pairs, in the innodb_memcache.containersentry associated with the MySQL table, specify in the

value_columnsfield several column names separated by comma, semicolon, space, or pipę

characters; for example, coll,col2_#col3 or coli I col2 I col3.

Concatenate the column values into a single string using the pipę character as a separator, before

passing that string to memcached add or set calls. The string is unpacked automatically into the

various columns. Each get cali returns a single string with the column values, also delimited by the

pipę separator character. you unpack those values using the appropriate syntax

depending on your

applicationlanguage.