Implement #8928 : Add limit for max value of -PARALLEL switch value when restoring a database

Author: hvlad

doc/README.gbak

@@ -63,9 +63,12 @@ this case engine will use value of ParallelWorkers setting when building
 indices, i.e. this phase could be run in parallel by the engine itself. To 
 fully avoid parallel operations when restoring database, use -PARALLEL 1.
 
-  Note, gbak not uses firebird.conf by itself and ParallelWorkers setting does
+  Note: gbak not uses firebird.conf by itself and ParallelWorkers setting does
 not affect its operations.
 
+  Note: the upper limit for the number of parallel workers is 64 and applied by
+both backup and restore.
+
 
 Examples.
 

src/burp/burp.cpp

@@ -899,6 +899,8 @@ int gbak(Firebird::UtilSvc* uSvc)
 				BURP_error(408, true, argv[itr]);
 				// msg 408 expected parallel workers, encountered "%s"
 			}
+			if (tdgbl->gbl_sw_par_workers > BURP_MAX_PARALLEL_WORKERS)
+				tdgbl->gbl_sw_par_workers = BURP_MAX_PARALLEL_WORKERS;
 			break;
 		case IN_SW_BURP_Y:
 			{

src/burp/burpswi.h

@@ -239,6 +239,7 @@ static const char* burp_repl_mode_sw_table[] =
 	BURP_SW_MODE_NONE, BURP_SW_MODE_RO, BURP_SW_MODE_RW
 };
 
+const int BURP_MAX_PARALLEL_WORKERS = 64;
 
 #endif // BURP_BURP_H