This returns the combined memory limit for all tables. The value is given in Kilo-Bytes. This is a combined limit for all tables, not an individual table limit. Once this limit is reached attempts to add data to tables will receive a MEMORY_EXCEEDED error. The value 0 indicates there is no limit, the server will continue to allocate memory until the process limit is exceeded, at which point it will abort. The special value -1 indicates no memory limit information was returned.