I would like get some more details about what STATISTICS and OPTIMIZE do.
The general idea is that Cubrid keeps track of some information which is used for optimizing query exection. If you are doing a lot of database modifications without updating statistics your queries might get slow.
You can update statistics using the cubrid optimizedb options database_name command. You can find more info about it here: http://www.cubrid.org/manual/840/en/Database%20Administration-Updating%20Statistics
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