A description of the database and public window entry preferences and their functionality.
The following additional preferences apply only to database and public window service entries. Sybase CEP Engine uses these preferences only for direct CCL connections to the database via the Database Statement or database subqueries. You cannot set these preferences for use with adapters.
"DBWriteMaxBatchSize"
This preference determines how many database writes Sybase CEP Engine may send to the database from a CCL Database Statement in a single batch. You can specify a value between 1 and 65536 for this preference. The default value is 1. "DBWriteMaxBatchSize" affects only requests that are already in the processing queue - Sybase CEP Server does not wait for the maximum number of requests to accumulate before executing them. Sybase CEP Engine does not support batching for BLOB and XML data types. Since public windows do not accept database writes, this preference does not affect public windows. "DBWriteMaxBatchSize" also has no effect on Oracle TimesTen connections.
Some ODBC databases (such as MySQL's ODBC driver) do not support batch sizes of greater than 1 for stored procedure calls, such as the CALL statement or BEGIN ...END blocks. These databases may not issue an error for the unsupported batch size, but may simply ignore subsequent data after the first call in the batch. The MySQL ODBC driver also does not support batching for INSERT, DELETE and UPDATE statements.
If you are using a "DBWriteMaxBatchSize" of more than one 1, in conjunction with an ODBC database connection and are using stored procedure calls, verify that your database is receiving all the expected data from your batch before using this setting in a production environment. Do not set a "DBWriteMaxBatchSize" of more than one 1 when using a MySQL ODBC driver.
"DBReadNoCommit"
By default, Sybase CEP automatically issues an SQL COMMIT after every executed database statement, regardless of whether the statement is a read or a write. If this is affecting performance on your database reads, the "DBReadNoCommit" preference can be set to TRUE (from its default setting of FALSE ) to disable the commits for database subquery execution only. Note that enabling this option prevents you from issuing SELECT FOR UPDATE and other SQL statements that require a COMMIT. Since public windows do not accept database writes, this preference does not affect on public windows.
"DBDriverCharBufferSize"
The "DBDriverCharBufferSize" preference specifies the size of the Sybase CEP Server buffer for sending any data to and receiving any data from an external database. This preference can be set to an integer between 1 and 65536. The default value is 4096.
Sybase CEP Server generates errors in response to any attempt to send or receive data larger than the specified buffer size maximum (or larger than the default value, if no maximum is specified). Sybase CEP Engine does not support buffer sizes that exceed the 65536 maximum, even when external databases support such buffer sizes.
This preference does not affect public windows or connections to kdb+ databases, both of which supports an unlimited buffer size.
"DBDriverNoBigintSupport"
Some ODBC drivers (especially older pre ODBC 3.51 versions) do not have native support for 64-bit integers. Set the"DBDriverNoBigintSupport" preference to TRUE or FALSE to notify Sybase CEP Server whether or not the underlying ODBC driver or database supports native 64-bit integer transfers. A settings of TRUE indicates that the ODBC driver or database does not support native 64-bit integer transfers, and prompts Sybase CEP Server to transparently convert 64-bit integers into strings. Note that you may slow down data transfer by enabling this preference. The default setting for "DBDriverNoBigintSupport" is FALSE .
If you are not sure whether your ODBC driver supports 64-bit integers, set "DBDriverNoBigintSupport" to FALSE . If you then detect messages related to LONG, TIMESTAMP or INTERVAL data types, try changing this preference to TRUE and then restarting Sybase CEP Server.
You must set this preference to TRUE when using the Oracle TimesTen database.