Reading Oracle Deadlock Trace File

Managing Oracle Database Processes. Shared memory resources are preconfigured to allow the enabling of shared server at run time. You need not configure it by specifying parameters in your initialization parameter file, but you can do so if that better suits your environment. You can start dispatchers and shared server processes shared servers dynamically using the ALTER SYSTEM statement. This section discusses how to enable shared server and how to set or alter shared server initialization parameters. It contains the following topics Initialization Parameters for Shared Server. The following initialization parameters control shared server operation SHAREDSERVERS Specifies the initial number of shared servers to start and the minimum number of shared servers to keep. This is the only required parameter for using shared servers. Solve your Oracle errors quickly and easily with this list of advice from Oracle experts on common error messages. Oracle News for the professional. Included Tips Page starts here Tagged. Oracle Database Tips by Donald BurlesonJune 30, 2013. Semester Computer engineering Polytechnic Classes in Nagpur,MSBTE Poly 5th sem Computer Tuition in Nagpur, Polytechnic Fifth Semester computer engineering Batches. YMDlr.png' alt='Reading Oracle Deadlock Trace File' title='Reading Oracle Deadlock Trace File' />MAXSHAREDSERVERS Specifies the maximum number of shared servers that can run simultaneously. SHAREDSERVERSESSIONS Specifies the total number of shared server user sessions that can run simultaneously. Setting this parameter enables you to reserve user sessions for dedicated servers. DISPATCHERS Configures dispatcher processes in the shared server architecture. MAXDISPATCHERS Specifies the maximum number of dispatcher processes that can run simultaneously. This parameter can be ignored for now. It will only be useful in a future release when the number of dispatchers is auto tuned according to the number of concurrent connections. CIRCUITS Specifies the total number of virtual circuits that are available for inbound and outbound network sessions. Enabling Shared Server. Shared server is enabled by setting the SHAREDSERVERS initialization parameter to a value greater than 0. RLEF7uM/U3HDr0A9elI/AAAAAAAAEGo/tgSjMfk_T7Q/s1600/Image+last.png' alt='Reading Oracle Deadlock Trace File' title='Reading Oracle Deadlock Trace File' />Moved Permanently. The document has moved here. This chapter explains the nature of an Oracle database instance, the parameter and diagnostic files associated with an instance, and what occurs during instance. The other shared server initialization parameters need not be set. Because shared server requires at least one dispatcher in order to work, a dispatcher is brought up even if no dispatcher has been configured. Dispatchers are discussed in Configuring Dispatchers. Shared server can be started dynamically by setting the SHAREDSERVERS parameter to a nonzero value with the ALTER SYSTEM statement, or SHAREDSERVERS can be included at database startup in the initialization parameter file. If SHAREDSERVERS is not included in the initialization parameter file, or is included but is set to 0, then shared server is not enabled at database startup. Note. For backward compatibility, if SHAREDSERVERS is not included in the initialization parameter file at database startup, but DISPATCHERS is included and it specifies at least one dispatcher, shared server is enabled. In this case, the default for SHAREDSERVERS is 1. However, if neither SHAREDSERVERS nor DISPATCHERS is included in the initialization file, you cannot start shared server after the instance is brought up by just altering the DISPATCHERS parameter. You must specifically alter SHAREDSERVERS to a nonzero value to start shared server. Determining a Value for SHAREDSERVERSThe SHAREDSERVERS initialization parameter specifies the minimum number of shared servers that you want created when the instance is started. After instance startup, Oracle Database can dynamically adjust the number of shared servers based on how busy existing shared servers are and the length of the request queue. In typical systems, the number of shared servers stabilizes at a ratio of one shared server for every ten connections. For OLTP applications, when the rate of requests is low, or when the ratio of server usage to request is low, the connections to servers ratio could be higher. In contrast, in applications where the rate of requests is high or the server usage to request ratio is high, the connections to server ratio could be lower. BmiRy.png' alt='Reading Oracle Deadlock Trace File' title='Reading Oracle Deadlock Trace File' />The PMON process monitor background process cannot terminate shared servers below the value specified by SHAREDSERVERS. Therefore, you can use this parameter to stabilize the load and minimize strain on the system by preventing PMON from terminating and then restarting shared servers because of coincidental fluctuations in load. If you know the average load on your system, you can set SHAREDSERVERS to an optimal value. The following example shows how you can use this parameter Assume a database is being used by a telemarketing center staffed by 1. On average, each agent spends 9. To keep the shared servers from being terminated as agents talk to customers and then spawned again as agents access the database, a DBA specifies that the optimal number of shared servers is 1. However, not all work shifts are staffed at the same level. On the night shift, only 2. Since SHAREDSERVERS is a dynamic parameter, a DBA reduces the number of shared servers to 2. Decreasing the Number of Shared Server Processes. Sony Vegas 4.0 Keygen 11 Plus there. You can decrease the minimum number of shared servers that must be kept active by dynamically setting the SHAREDSERVERS parameter to a lower value. Thereafter, until the number of shared servers is decreased to the value of the SHAREDSERVERS parameter, any shared servers that become inactive are marked by PMON for termination. The following statement reduces the number of shared servers. ALTER SYSTEM SET SHAREDSERVERS 5. Setting SHAREDSERVERS to 0 disables shared server. For more information, please refer to Disabling Shared Servers. Limiting the Number of Shared Server Processes. The MAXSHAREDSERVERS parameter specifies the maximum number of shared servers that can be automatically created by PMON. It has no default value. If no value is specified, then PMON starts as many shared servers as is required by the load, subject to these limitations The process limit set by the PROCESSES initialization parameterA minimum number of free process slots at least one eighth of the total process slots, or two slots if PROCESSES is set to less than 2. System resources. Note. On Windows NT, take care when setting MAXSHAREDSERVERS to a high value, because each server is a thread in a common process. The value of SHAREDSERVERS overrides the value of MAXSHAREDSERVERS. Therefore, you can force PMON to start more shared servers than the MAXSHAREDSERVERS value by setting SHAREDSERVERS to a value higher than MAXSHAREDSERVERS. You can subsequently place a new upper limit on the number of shared servers by dynamically altering the MAXSHAREDSERVERS to a value higher than SHAREDSERVERS. The primary reason to limit the number of shared servers is to reserve resources, such as memory and CPU time, for other processes. For example, consider the case of the telemarketing center discussed previously The DBA wants to reserve two thirds of the resources for batch jobs at night. He sets MAXSHAREDSERVERS to less than one third of the maximum number of processes PROCESSES. By doing so, the DBA ensures that even if all agents happen to access the database at the same time, batch jobs can connect to dedicated servers without having to wait for the shared servers to be brought down after processing agents requests. Another reason to limit the number of shared servers is to prevent the concurrent run of too many server processes from slowing down the system due to heavy swapping, although PROCESSES can serve as the upper bound for this rather than MAXSHAREDSERVERS. Still other reasons to limit the number of shared servers are testing, debugging, performance analysis, and tuning.