Adaptive Server records individual thread pool information
in the configuration file under the Thead Pool heading.
By default, Adaptive Server includes a set of system thread pools that are required for it to function. These include the syb_default_pool engine pool and multiple run to completion (RTC) thread pools, which do not contain engines. Users can create their own thread pools in addition to the system pools. User created thread pools are always engine pools.
For more details on thread pool types, see “Thread pools”.
At start-up, Adaptive Server lists information for syb_default_pool and syb_blocking_pool, with their parameters set to the default values; the information for syb_system_pool is not included because Adpative Server calculates its number of threads at runtime, based on other configuration demands.
The configuration file lists these parameters for all thread pools:
number of threads – configured number of threads in the pool.
description – brief description of pool.
When Adaptive Server starts, this is the default thread pool configuration:
[Thread Pool:syb_blocking_pool] number of threads = 4 [Thread Pool:syb_default_pool] number of threads = 1
As you add or remove thread pools, Adaptive Server updates the configuration file, but does not require a restart for the changes to take effect. User-created thread pools (that you create with create thread pool) must be engine pools.
This example includes the two Sybase-provided thread pools and a user-created thread pool, sales_pool:
[Thread Pool:sales_pool] description = pool for the sales force number of threads = 14
idle timeout = 75 [Thread Pool:syb_blocking_pool] number of threads = 20 [Thread Pool:syb_default_pool] number of threads = 1
Use a file editor to edit the thread pool information in the configuration file, or use the create thread pool, alter thread pool, and drop thread pool commands to administer thread pools. See the Reference Manual: Commands.
If you edit the configuration file, Adaptive Server starts using the new thread pool configuration, printing any change information to the log file (if you add thread pools with create thread pool, you need not restart Adaptive Server). This output is from the log file after adding the smaller_pool thread pool to Adaptive Server:
00:0000:00000:00000:2010/06/03 16:09:56.22 kernel Create Thread Pool 4, "smaller_pool", type="Engine (Multiplexed)", with 10 threads
In isql, use create thread pool to add thread pools. This example adds the sales_pool thread pool with 5 threads:
create thread pool sales_pool with thread count = 1
Use sp_helpthread to determine the runtime values for thread pools, including syb_system_pool. This is the sp_helpthread output for the thread pools above:
sp_helpthread
Name Type Size IdleTimeout Description ----------------- -------------------- ---- ----------- -------------------------------------------- sales_pool Engine (Multiplexed) 1 100 NULL syb_blocking_pool Run To Completion 4 0 A pool dedicated to executing blocking calls syb_default_pool Engine (Multiplexed) 1 100 The default pool to run query sessions syb_system_pool Run To Completion 4 0 The I/O and system task pool
To drop the sales_pool thread pool, use:
drop thread pool sales_pool
See the Reference Manual: Commands.
You may see a message similar to this when you create a thread pool with an insufficient amount of memory (determined with kernel resource memory) to create the threads and there are an insufficient number of engines available:
00:0001:00000:00011:2010/06/11 14:46:38.32 kernel Setting console to nonblocking mode. 00:0001:00000:00011:2010/06/11 14:46:38.32 kernel Create thread pool pubs_pool 00:0001:00000:00011:2010/06/11 14:46:38.32 kernel Create Thread Pool 4, "pubs_pool", type="THREADPOOL_MULTIPLEXED", with 2 threads 00:0001:00000:00011:2010/06/11 14:46:38.32 kernel could not allocate memory for dynamic engine 00:0001:00000:00011:2010/06/11 14:46:38.32 kernel Thread creation failed to allocate an engine. 00:0001:00000:00011:2010/06/11 14:46:38.32 server Configuration file '/sybase/siena.cfg' has been written and the previous version has been renamed to '/sybase/siena.009'. 1> 00:0025:00000:00000:2010/06/11 14:46:38.33 kernel Network and device connection limit is 1009. 00:0025:00000:00000:2010/06/11 14:46:38.33 kernel ASE - Dynamic Pluggable Component Interface is disabled 00:0025:00000:00000:2010/06/11 14:46:38.33 kernel Encryption provider initialization succeeded on engine 1. 00:0025:00000:00000:2010/06/11 14:46:38.33 kernel Thread 25 (LWP 15726) of Threadpool pubs_pool online as engine 1
To create the thread pool, increase the value of max online engines, and restart Adaptive Server.
