Buffered message queue architecture for database management systems with ...

^ ^208

SUBSCRIBER REQUESTS THAT A MESSAGE BE DEQUEUED FROM
BUFFERED MESSAGE QUEUE

210

DETERMINE WHETHER FIRST MESSAGE SATISFIES SUBSCRIPTION
DATA FOR SUBSCRIBER

212

PROVIDE FIRST MESSAGE TO SUBSCRIBER IF FIRST MESSAGE
SATISFIES SUBSCRIPTION DATA

214

DELETE FIRST MESSAGE FROM MESSAGE QUEUE IF FIRST MESSAGE
DOES NOT SATISFY ANY OTHER SUBSCRIPTION DATA

FIG. 4

400

402

RECEIVE REQUEST TO ENQUEUE A NEW MESSAGE INTO A BUFFERED MESSAGE QUEUE FOR WHICH THERE IS INSUFFICIENT SPACE IN THE BUFFERED MESSAGE QUEUE

404

SPILLOVER TO NON-VOLATILE STORAGE EITHER CURRENT MESSAGES IN BUFFERED MESSAGE QUEUE OR NEW MESSAGE

406

STORE MESSAGE HEADER IN BUFFERED MESSAGE QUEUE FOR
SPILLED OVER MESSAGE

408

STORE NEW MESSAGE IN BUFFERED MESSAGE QUEUE