A_SYB_EXTRA_PROC can be used to keep modifications to the AcuLocks table out of transactions. If these modifications are kept out of transactions, users can read a record, even if they cannot REWRITE it. Otherwise, they are locked out. A_SYB_EXTRA_PROC works by creating a separate connection for these modifications.
When this variable is set to a nonzero value, an extra connection is used for the following three procedures:
The default value is 0 (OFF, FALSE, NO). A nonzero value can also be represented by ON (TRUE, YES).
If this variable is set to On, the extra connection is used to send TEXT or IMAGE data to the server. The first connection is used to deliver non-TEXT and non-IMAGE data to the server. When a WRITE or REWRITE is executed, the interface program INSERTS or UPDATES the non-TEXT and non-IMAGE data by using placeholder data in the TEXT or IMAGE columns.
The TEXT or IMAGE data is then sent using the extra connection established with the A_SYB_EXTRA_PROC configuration variable. If the first connection is inside a transaction, the second connection is locked out of the row that is added or updated. The result is that it is not possible to WRITE or REWRITE records containing TEXT or IMAGE data while inside a transaction.
See also: Record and Table Locking.