This configuration variable turns on the caching of data blocks for file reads.
By default, files for Vision 4 and later do not internally cache data blocks (all V_BUFFERS are allocated only to index blocks). This allows the V_LOCK_METHOD configuration variable to work properly when set to 2. You must set V_NO_ASYNC_CACHE_DATA for Vision 2 or 3 files if record data caching is desired.
The default setting of this configuration variable is 0 (off). Set this configuration variable to 1 only if you are not using the asynchronous reads feature at all, which can improve READ performance.