When will EMS server read the messages from the disk?
Article ID: KB0091497
Updated On:
| Products | Versions |
|---|---|
| TIBCO Enterprise Message Service | - |
| Not Applicable | - |
Description
Resolution:
The server will have to read the messages from disk in several situations:
1. Messages could be swapped out on certain siturations, for more detail, please refer to FAQ: When will EMS server swap out messages.
When this happens, the server will need to read the messages from disk in order to send them to the consumers
2. Starting a new consumer on a queue or offline durable will require PERSISTENT pending messages to be read from disk. Note that newly started queue consumers with selector will cause the server to read all pending swapped-out messages from disk, until the prefetched number of messages satisfying the selector is reached.
3. When you run a queue browser, the EMS server need to load the message from the store to memory.
4. When EMS server is started.
You can set the global parameter "msg_swapping" to "disabled" in the main configuration file in order to prevent the EMS Server to ever free the messages from memory. No disk read is then needed when the server needs to send messages to consumers, since they are entirely in memory. Of course, this requires much more memory to store an equivalent number of messages than when msg_swapping is enabled. For more detail, please refer to "FAQ1-9BA0IC: When will EMS server swap out messages".
The server will have to read the messages from disk in several situations:
1. Messages could be swapped out on certain siturations, for more detail, please refer to FAQ: When will EMS server swap out messages.
When this happens, the server will need to read the messages from disk in order to send them to the consumers
2. Starting a new consumer on a queue or offline durable will require PERSISTENT pending messages to be read from disk. Note that newly started queue consumers with selector will cause the server to read all pending swapped-out messages from disk, until the prefetched number of messages satisfying the selector is reached.
3. When you run a queue browser, the EMS server need to load the message from the store to memory.
4. When EMS server is started.
You can set the global parameter "msg_swapping" to "disabled" in the main configuration file in order to prevent the EMS Server to ever free the messages from memory. No disk read is then needed when the server needs to send messages to consumers, since they are entirely in memory. Of course, this requires much more memory to store an equivalent number of messages than when msg_swapping is enabled. For more detail, please refer to "FAQ1-9BA0IC: When will EMS server swap out messages".
Issue/Introduction
When will EMS server read the messages from the disk?
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