Can copy and compare be run concurrently on different tables?
There is nothing that will prevent copy and compare from being run at the same time. There can be some showstoppers depending on the size of the tables being copied/compared. If the tables are large and the copy and compare are expected to finish in more than 30 minutes, then depending on which of these two commands was issued first, the second command will fail due to timeout. For example, if copy was run on table A and soon afterwards compare was run on table B and assuming that both commands are expected to take an hour to finish, then copy will succeed but compare will timeout and vice versa. This assumes that the parameter that determines the timeout (SP_DEQ_TIMEOUT for compare and SP_OSY_TIMEOUT for copy) are set to the default of 30 minutes. If these parameters are set to a higher value, the timeout can still be avoided but the point is, it is possible for the later process to timeout if the former process will take a time which is higher than the timeout of the latter process.
When copy or compare are run, SharePlex considers the changes taking place on the source table when resynchronizing the target table. It takes a read consistent view of the source table, then sends a marker to Post on target (a kind of token message) then allows user access to the source table, then suspends posting on the target table (once that marker reaches the target) till the copy or compare syncs the target table. Depending on which command was issued first, the marker for the second command does not reach the target within the stipulated time resulting in timeout for the second command.
Keywords:
compare
copy
simultaneous
parallel
together
