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The MEMORY storage engine can either be a blessing or a curse depending on

• what you intend to store
• how often you plan to perform DML
• how much RAM you leaving for the
• Database caches (MyISAM Key Cache, InnoDB Buffer Pool)
• OS caches
• OS operation

The MEMORY storage engine

• uses full table locking for INSERTs, UPDATEs, and DELETEs
• Cannot perform concurrent INSERTs
• uses the hash indexes instead of BTREE indexes by default
• can use BTREEs indexes, but must be explicitly specified at CREATE TABLE time
• has no transaction support

Even though you have data in RAM, mysqld will always hit the .frm file to check for the table existing as a reference point, thus always incurring a little disk I/O. Proportionally, heavy access to a MEMORY storage engine table will have noticeable disk I/O.

The MEMORY storage engine can either be a blessing or a curse depending on

• what you intend to store
• how often you plan to perform DML
• how much RAM you leaving for the
• Database caches (MyISAM Key Cache, InnoDB Buffer Pool)
• OS caches
• OS operation

The MEMORY storage engine

• uses full table locking for INSERTs, UPDATEs, and DELETEs
• Cannot perform concurrent INSERTs
• uses the hash indexes instead of BTREE indexes by default
• can use BTREEs indexes, but must be explicitly specified at CREATE TABLE time
• has no transaction support
• Single row queries are just great against MEMORY tables, especially using HASH indexes -- Ranged queries and sequential access are just horrific unless you use BTREE explicitly (more memory consumption required)

Even though you have data in RAM, mysqld will always hit the .frm file to check for the table existing as a reference point, thus always incurring a little disk I/O. Proportionally, heavy access to a MEMORY storage engine table will have noticeable disk I/O.

The MEMORY storage engine can either be a blessing or a curse depending on

• what you intend to store
• how often you plan to perform DML
• how much RAM you leaving for the
• Database caches (MyISAM Key Cache, InnoDB Buffer Pool)
• OS caches
• OS operation

The MEMORY storage engine

• uses full table locking for INSERTs, UPDATEs, and DELETEs
• Cannot perform concurrent INSERTs
• uses the hash indexes instead of BTREE indexes by default
• can use BTREEs indexes, but must be explicitly specified at CREATE TABLE time
• has no transaction support
• Even though you have data in RAM, mysqld will always hit the .frm file to check for the table existing as a reference point, thus always incurring a little disk I/O. Proportionally, heavy access to a MEMORY storage engine table will have noticeable disk I/O.

The MEMORY storage engine can either be a blessing or a curse depending on

• what you intend to store
• how often you plan to perform DML
• how much RAM you leaving for the
• Database caches (MyISAM Key Cache, InnoDB Buffer Pool)
• OS caches
• OS operation

The MEMORY storage engine

• uses full table locking for INSERTs, UPDATEs, and DELETEs
• Cannot perform concurrent INSERTs
• uses the hash indexes instead of BTREE indexes by default
• can use BTREEs indexes, but must be explicitly specified at CREATE TABLE time
• has no transaction support

Even though you have data in RAM, mysqld will always hit the .frm file to check for the table existing as a reference point, thus always incurring a little disk I/O. Proportionally, heavy access to a MEMORY storage engine table will have noticeable disk I/O.

The MEMORY storage engine can either be a blessing or a curse depending on

• what you intend to store
• how often you plan to perform DML
• how much RAM you leaving for the
• Database caches (MyISAM Key Cache, InnoDB Buffer Pool)
• OS caches
• OS operation

The MEMORY storage engine

• uses full table locking for INSERTs, UPDATEs, and DELETEs
• Cannot perform concurrent INSERTs
• uses the hash indexes instead of BTREE indexes by default
• can use BTREEs indexes, but must be explicitly specified at CREATE TABLE time
• has no transaction support

The MEMORY storage engine can either be a blessing or a curse depending on

• what you intend to store
• how often you plan to perform DML
• how much RAM you leaving for the
• Database caches (MyISAM Key Cache, InnoDB Buffer Pool)
• OS caches
• OS operation

The MEMORY storage engine

• uses full table locking for INSERTs, UPDATEs, and DELETEs
• Cannot perform concurrent INSERTs
• uses the hash indexes instead of BTREE indexes by default
• can use BTREEs indexes, but must be explicitly specified at CREATE TABLE time
• has no transaction support
• Even though you have data in RAM, mysqld will always hit the .frm file to check for the table existing as a reference point, thus always incurring a little disk I/O. Proportionally, heavy access to a MEMORY storage engine table will have noticeable disk I/O.