Sun GlassFish Message Queue 4.4 Administration Guide

Persistence Properties

Message Queue supports both file-based and JDBC-based persistence modules. The broker property imq.persist.store (Table 17–4) specifies which module to use. The following sections describe the broker configuration properties for the two modules.

Table 17–4 Global Broker Persistence Property


Property	Type	Default Value	Description
`imq.persist.store`	String	`file`	Module used for persistent data storage: `file`: File-based persistence `jdbc`: JDBC-based persistence Must be set to `jdbc` for enhanced broker clusters (`imq.cluster.ha` = `true`).

File-Based Persistence Properties

Table 17–5 lists the broker properties related to file-based persistence.

Table 17–5 Broker Properties for File-Based Persistence


Property	Type	Default Value	Description
`imq.persist.file.message.max_record_size`	String	`1m`	Maximum-size message to add to message storage file Any message exceeding this size will be stored in a separate file of its own.
			The value may be expressed in bytes, kilobytes, or megabytes, using the following suffixes: `b`: Bytes `k`: Kilobytes (1024 bytes) `m`: Megabytes (1024 × 1024 = 1,048,576 bytes) An unsuffixed value is expressed in bytes.
			Examples: `1600`: 1600 bytes `1600b`: 1600 bytes `16k`: 16 kilobytes (= 16,384 bytes) `16m`: 16 megabytes (= 16,777,216 bytes)
`imq.persist.file.destination.message.filepool.limit`	Integer	`100`	Maximum number of free files available for reuse in destination file pool Free files in excess of this limit will be deleted. The broker will create and delete additional files in excess of the limit as needed. The higher the limit, the faster the broker can process persistent data.
`imq.persist.file.message.filepool.cleanratio`	Integer	`0`	Percentage of files in free file pools to be maintained in a clean (empty) state The higher this value, the less disk space is required for the file pool, but the more overhead is needed to clean files during operation.
`imq.persist.file.message.cleanup`	Boolean	`false`	Clean up files in free file pools on shutdown? Setting this property to `true` saves disk space for the file store, but slows broker shutdown.
`imq.persist.file.sync.enabled`	Boolean	`false`	Synchronize in-memory state with physical storage device? Setting this property to `true` eliminates data loss due to system crashes, but at a cost in performance. Note – If running Sun Cluster and the Sun Cluster Data Service for Message Queue, set this property to `true` for brokers on all cluster nodes.
`imq.persist.file.transaction.memorymappedfile.enabled`	Boolean	`true`	Use memory-mapped file to store transaction data? Setting this property to `true` improves performance at the cost of increased memory usage. Set to `false` for file systems that do not support memory-mapped files.

File-Based Persistence Properties for Transaction Logging

Table 17–6 lists the file-based persistence properties for the transaction logging mechanism introduced in Message Queue 4.4 Update 1.

Table 17–6 Broker Properties for File-Based Persistence Using the Transaction Logging Mechanism


Property	Type	Default Value	Description
`imq.persist.file.newTxnLog.enabled`	Boolean	`false`	Enables the transaction logging mechanism introduced in Message Queue 4.4 Update 1. For information about this mechanism, see Optimizing File-Based Transaction Persistence.
`imq.persist.file.txnLog.groupCommit`	Boolean	`false`	This property is applicable only if `imq.persist.file.newTxnLog.enabled` is `true`. Can improve performance if `imq.persist.file.sync.enabled` is `true` and the number of concurrent transactions being processed is high: If `true`, write operations to the transaction log are not handled by individual connection threads; instead, writes from connection threads are added to a transaction queue. The connection threads then wait until they are notified that the transactions have been logged. A separate thread periodically drains the transaction queue and writes it to the transaction log. When possible, this thread groups together multiple active transactions and writes them to the transaction log in a single operation. After the write completes, waiting client threads are notified. If `false`, write operations to the transaction log are handled by individual connection threads. Only one thread at a time is able to write to the log.
`imq.persist.file.txnLog.logNonTransactedMsgSend`	Boolean	`false`	This property is applicable only if `imq.persist.file.newTxnLog.enabled` is `true`. Overrides the behavior for persisting non-transacted messages (as defined by the `imq.persist.file.sync.enabled` property): If `true`, non-transacted messages are written to the transaction log before they are written to the persistent store. If `false`, non-transacted messages are written directly to the persistent store.
`imq.persist.file.txnLog.logNonTransactedMsgAck`	Boolean	`false`	This property is applicable only if `imq.persist.file.newTxnLog.enabled` is `true`. Overrides the behavior for persisting non-transacted message acknowledgements (as defined by the `imq.persist.file.sync.enabled` property): If `true`, acknowledgements of non-transacted messages are written to the transaction log before they are written to the persistent store. If `false`, acknowledgements of non-transacted messages are written directly to the persistent store.

JDBC-Based Persistence Properties

Table 17–7 lists the broker properties related to JDBC-based persistence. The first of these properties, imq.persist.jdbc.dbVendor, identifies the database vendor being used for the broker’s persistent data store; all of the remaining properties are qualified by this vendor name.

Table 17–7 Broker Properties for JDBC-Based Persistence


Property	Type	Default Value	Description
`imq.persist.jdbc.dbVendor`	String	None	Name of database vendor for persistent data store: `hadb`: HADB (Sun Microsystems, Inc.) `derby`: Java DB (Sun Microsystems, Inc.) `oracle`: Oracle (Oracle Corporation) `mysql`: MySQL (Sun Microsystems, Inc.) `postgresql`: postgreSQL
`imq.persist.jdbc.connection.limit`	Integer	`5`	The maximum number of connections that can be opened to the database.
`imq.persist.jdbc.vendorName.driver`	String	per vendor	Java class name of JDBC driver, if needed, for connecting to database from vendor `vendorName`
`imq.persist.jdbc.vendorName.opendburl`	String	None	URL for connecting to existing database from vendor `vendorName` Applicable when driver is used to connect to database.
`imq.persist.jdbc.vendorName.createdburl` [Optional]	String	None	URL for creating new database from vendor `vendorName` Applies for embedded database, such as Java DB.
`imq.persist.jdbc.vendorName.closedburl`	String	None	URL for closing connection to database from vendor `vendorName` Applies for some embedded databases, such as Java DB.
`imq.persist.jdbc.vendorName.user`	String	None	User name, if required, for connecting to database from vendor `vendorName` For security reasons, the value can instead be specified using command line options `imqbrokerd -dbuser` and `imqdbmgr -u`.
`imq.persist.jdbc.vendorName.needpassword`	Boolean	`false`	Does database from vendor `vendorName` require a password for broker access? If `true`, the `imqbrokerd` and `imqdbmgr` commands will prompt for a password, unless you use the `-passfile` option to specify a password file containing it.
`imq.persist.jdbc.vendorName.password`^, [Should be used only in password files]	String	None	Password, if required, for connecting to database from vendor `vendorName`
`imq.persist.jdbc.vendorName.property.propName`	String	None	Vendor-specific property `propName` for database from vendor `vendorName`
`imq.persist.jdbc.vendorName.tableoption`	String	None	Vendor-specific options passed to the database when creating the table schema.