Adaptive Server transaction coordination services can ensure that the work of remote servers is logically committed or rolled back provided that each remote Adaptive Server is at version 12.0 and later.
Transaction coordination services are transparent to the client executing the distributed transaction. When a local client transaction executes a RPC or updates data via CIS, the coordination service creates a new transaction name for the remote work and propagates that transaction to the subordinate, remote server. When the local client commits or rolls back the local transaction, Adaptive Server coordinates that request with each of the subordinate servers to ensure that the remote transactions are committed or rolled back as well.
The Adaptive Server transaction coordination service runs as one or more background tasks named “ASTC HANDLER,” and can be viewed using sp_who. In systems using multiple Adaptive Server engines, the number of “ASTC HANDLER” processes (rounded down to the nearest whole number) is:
number of engines * 2/3
There can be a maximum of 4 “ASTC HANDLER” processes running on Adaptive Server.
The following output from sp_who shows a single “ASTC HANDLER”:
sp_who
fid spid status loginame origname hostname blk_spid dbname tempdbname cmd block_xloid threadpool --- ---- --------- --------- --------- ---------------- -------- ----------- ----------- ----------------- ----------- ----------------- 0 1 running sa sa dtmsol1 0 master tempdb SELECT 0 syb_default_pool 0 2 sleeping NULL NULL master 0 master tempdb NETWORK HANDLER 0 syb_default_pool 0 3 sleeping NULL NULL 0 master tempdb DEADLOCK TUNE 0 syb_default_pool 0 4 sleeping NULL NULL 0 master tempdb MIRROR HANDLER 0 syb_default_pool 0 5 sleeping NULL NULL 0 master tempdb HOUSEKEEPER 0 syb_default_pool 0 6 sleeping NULL NULL 0 master tempdb CHECKPOINT SLEEP 0 syb_default_pool 0 7 sleeping NULL NULL metin1_dtm 0 sybsystemdb tempdb ASTC HANDLER 0 syb_default_pool
