Birt Engine 使用

当Birt ReportTemplate 设计缺陷或者由于数据量巨大，有可能导致内存溢出问题。

可以通过调整Birt Engine 的相关参数避免问题的产生，可以调整一下参数。 Buffer 的单位均为MB

ID

API

Description For API

Value To Be Set

1	DataEngine.MEMORY_BUFFER_SIZE	Indicate the size of data cached for each result set. We only accept non-negative integer as input,  the unit of which would be MB.  If this setting is 0, all temporary rows will be cached in memory during query processing.	100
2	DataEngine.IN_MEMORY_CUBE_SIZE	The size of cube to be saved in memory rather than in disk. The unit is MB. In case that the size of materialized cube exceed the assigned memory size, the disk will automatically be used.	100
3	DataEngine.MEMORY_USAGE	Indicates data engine memory usage hint level MEMORY_USAGE_AGGRESSIVE:  This level is corresponding to 100% memory based MEMORY_USAGE_NORMAL: This level is corresponding to partly disk based MEMORY_USAGE_CONSERVATIVE: This level is corresponding to mainly disk based	DataEngine.MEMORY_USAGE_NORMAL

这样通过限制内存中的buffer 从而限制内存的使用，当内存不足时，将使用Disk作为Cache，可能造成性能稍微的下降，但可以避免内存溢出问题。

当内存空闲较大时，可以适当的放大 buffer 值。