You can improve record I/O performance by blocking records. When blocking is specified, the first read causes a whole block of records to be placed into a buffer. Subsequent read operations return a record from the buffer until the buffer is empty. At that time, the next block is fetched.
If you wish to block records when the FILE data type is used, open the file with blksize=value specified, where value indicates the block size. If blksize isspecified with a value of 0, a block size is calculated for you when you open a file.
If you wish to block records when the _RFILE data type is used, specify blkrcd = Y when you open the file.
Similar rules apply when blocking records for write operations.
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