Calculating the number of locks | Sun Microsystems 820434310

Tuning HADB

Calculating the number of locks

To calculate the number of locks needed, estimate the following parameters:

■Number of concurrent users that request session data to be stored in HADB (one session record per user)

■Maximum size of the BLOB session

■Persistence scope (max session data size in case of session/modified session and maximum number of attributes in case of modified session). This requires setAttribute() to be called every time the session data is modified.

If:

■x is the maximum number of concurrent users, that is, x session data records are present in the HADB, and

■y is the session size (for session/modified session) or attribute size (for modified attribute), Then the number of records written to HADB is:

xy/7000 + 2x

Record operations such as insert, delete, update and read will use one lock per record.

Note – Locks are held for both primary records and hot-standby records. Hence, for insert, update and delete operations a transaction will need twice as many locks as the number of records. Read operations need locks only on the primary records. During refragmentation and creation of secondary indices, log records for the involved table are also sent to the fragment replicas being created. In that case, a transaction needs four times as many locks as the number of involved records. (Assuming all queries are for the affected table.)

Summary

If refragmentation is performed, the number of locks to be configured is:

Nlocks = 4x (y/7000 + 2) = 2xy/3500 + 2x

Otherwise, the number of locks to be configured is:

Nlocks = 2x (y/7000 + 2) = xy/3500 + 4x

Tuning NumberOfLocks

Start with the default value. Look for exceptions with the indicated error codes in the Enterprise Server log files. Remember that under normal operations (no ongoing refragmentation) only half of the locks might be acquired by the client application.

To get information on allocated locks and locks in use, use the following command:

hadbm resourceinfo --locks

114	Sun GlassFish Enterprise Server 2.1 Performance Tuning Guide • January 2009

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Sun Microsystems 820434310 manual Calculating the number of locks, Summary, Tuning NumberOfLocks

Contents

Sun GlassFish Enterprise Server 2.1 Performance Tuning Guide Sun Microsystems, Inc Network Circle Santa Clara, CA 090304@21990 Contents Tuning the Enterprise Server 100 Tuning for High-Availability Figures Page Tables Page Examples Page Sun GlassFish Enterprise Server Documentation Set Table P-1Books in the Enterprise Server Documentation Set Default Paths and File Names Table P-2Default Paths and File Names Typographic Conventions Symbol ConventionsSymbol Conventions Table P-3Typographic Conventions Documentation, Support, and Training Third-Party Web Site ReferencesSun Welcomes Your Comments 1Performance Tuning Roadmap Process Overview Performance Tuning Sequence Performance Tuning Roadmap Understanding Operational Requirements Application Architecture Client-Side Presentation User Authentication and Authorization Security RequirementsEncryption Hardware Resources General Tuning Concepts Administration Capacity Planning 2Factors That Affect Performance User Expectations To Determine Capacity Further Information Java Programming Guidelines Avoid Serialization and DeserializationUse StringBuffer to Concatenate Strings Declare Methods as final Only If Necessary String str = testing str = str + abcAssign null to Variables That Are No Longer Needed Declare Constants as static final Declare Method Arguments final Java Server Page and Servlet TuningSynchronize Only When Necessary Use DataHandlers for Soap Attachments Avoid Shared Modified Class Variables Suggested Coding PracticesGeneral Guidelines Http Session Handling Configuration and Deployment Tips Disable Security ManagerOptimize SSL EJB Performance Tuning GoalsMonitoring EJB Components Following is a sample of the monitoring output Asadmin get -m monitorableObject Monitoring Individual EJB Components General Guidelines Use High Performance BeansUse Caching Use the Appropriate Stubs Using Local and Remote InterfacesCache and Pool Tuning Tips Remove Unneeded Stateful Session Beans Using Pass-By-Reference Semantics Prefer Local Interfaces Improving Performance of EJB Transactions Use the Least Expensive Transaction Attribute Using Special TechniquesConfigure Jdbc Resources as One-Phase Commit Resources Version Consistency Entity-mapping cmp-field-mapping Request Partitioning To enable request partitioningWhen new.VCVERSIONNUMBER = old.VCVERSIONNUMBER Declare Cmp-field-mapping consistency Tuning Tips for Specific Types of EJB Components Entity BeansStateful Session Beans Checkpoint only when needed Stateless Session BeansRead-Only Entity Beans Pre-fetching Container Managed Relationship CMR Beans Refresh period OrderTable.OrderID = OrderLineTable.OrderLineOrderID Encapsulate Business Logic in Entity EJB Components Jdbc and Database AccessUse Jdbc Directly Close Connections Use getConnection Tuning Message-Driven BeansAsadmin set server.mdb-container.max-pool-size = value Tune the Message-Driven Bean’s Pool Size Cache Bean-Specific Resources Limit Use of JMS Connections Tuning the Enterprise Server Deployment Settings Disable Dynamic Application Reloading Logger SettingsDisable Auto-deployment Use Pre-compiled JavaServer Pages Session Properties Session Timeout Web Container SettingsGeneral Settings Log Levels Disable Dynamic JSP Reloading Manager Properties Reap Interval Monitoring the EJB Container EJB Container SettingsTuning the EJB Container Overview of EJB Pooling and Caching Tuning the EJB Pool EJB Pool Settings Tuning the EJB Cache EJB Cache Settings Pool and Cache Settings for Individual EJB Components Commit Option Determining the best commit option Monitoring the Transaction Service Java Message Service SettingsTransaction Service Settings Viewing Monitoring Information Tuning the Transaction Service Disable Distributed Transaction LoggingAsadmin get -m serverInstance.transaction-service Recover On Restart Automatic Recovery Http Service SettingsMonitoring the Http Service Keypoint Interval Property name=statsProfilingEnabled value=false EnabledList --user admin --port DNS Cache Information dns Limit DNS Lookups to Asynchronous HitRatioCaching DNS Entries NameLookups File Cache Information file-cache Keep Alive keep-alive Connection Queue Tuning the Http ServiceAccess Log Request Processing Request Timeout Thread CountInitial Thread Count Keep Alive Buffer LengthMax Connections Http File Cache DNS Lookup EnabledHttp Protocol Time Out Max Age Max Files CountHash Init Size Small/Medium File Size and File Size Limit Tuning Http Listener Settings Network AddressAcceptor Threads How a Client Connects to the ORB ORB SettingsOverview Monitoring the ORB Connection Statistics Tuning the ORB3Tunable ORB Settings Thread Pools Tunable ORB Parameters ORB Thread Pool Parameters Using multiple connections Client ORB PropertiesControlling connections between client and server ORB Thread Pool Sizing Examining Iiop MessagesLoad Balancing Improving ORB Performance with Java Serialization To Enable Java Serialization Thread Pool SettingsTuning Thread Pools Unix /Linux only Using JSG for Application Clients Resources Jdbc Connection Pool SettingsTuning Jdbc Connection Pools Monitoring Jdbc Connection Pools Pool Size Settings Timeout Settings4Connection Pool Sizing Isolation Level Settings Connection Validation Settings Connector Connection Pool Settings Transaction Support Testpool Page Tuning the Java Runtime System Java Virtual Machine Settings Tuning the Garbage Collector Managing Memory and Garbage Collection Choosing the Garbage Collection Algorithm To use the CMS collectorAdditional Information Other Garbage Collector Settings Tracing Garbage Collection Tuning the Java Heap Guidelines for Java Heap Sizing1Maximum Address Space Per Process Heap Tuning Parameters Xmsvalue Xmxvalue Example 4-1Heap Configuration on Solaris Rebasing DLLs on WindowsSurvivor Ratio Sizing Enter this command rebase -b 0x6000000 *.dll To rebase the Application Server’s DLLs For more information on tuning the JVM, see Page Server Scaling Processors Memory Disk SpaceNetworking Tuning Parameters Sizing the Connection Hash Table Ndd -get /dev/tcp tcpconnhashNetstat -nP tcpwc -l Linux Configuration File Descriptor Setting Tuning for Solaris on File Descriptors on IP Stack Settings on IP Stack Settings File Descriptors Tuning for Linux platforms Virtual Memory Soft Nofile 65535 HardSession required /lib/security/pamlimits.so To tune the TCP/IP settings Disk I/O SettingsTCP/IP Settings Network Interface Tuning UltraSPARC T1-Based Systems Tuning Operating System and TCP Settings 2Tuning 64-bit Systems for Performance Benchmarking Disk Configuration Network ConfigurationStart Options 106 Tuning Hadb Disk UseCalculating Hadb Data Device Size Tuning Data Device Size Hadbm set TotalDatadeviceSizePerNode Beware last flush/fputs took too long Memory AllocationPlacing Hadb files on Physical Disks Vmstat -S Performance DataBufferPoolSizeNodeNo TotalSize FreeSize Usage 512 504 Tuning DataBufferPoolSize LogBufferSizeHadbm set DataBufferPoolSize Hadbm resourceinfo --logbuf Tuning LogBufferSizeInternalLogbufferSize Node No Avail Free Size Hadbm resourceinfo --nilogbuf Tuning InternalLogbufferSizeNumberOfLocks Hadbm set InternalLogbufferSize Tuning NumberOfLocks Calculating the number of locksSummary Load Balancer timeouts TimeoutsJdbc connection pool timeouts Node No Avail Free Waits 50000 Hadb timeouts Tuning the Enterprise Server for High-AvailabilityOperating System Configuration No space left on device Tuning Session Persistence Frequency Web-methodTime-based Session Session Persistence ScopeSession Size Modified-session Configuring the Jdbc Connection Pool Checkpointing Stateful Session Beans Configuring the Load Balancer Enabling the Health Checker Tuning for High-Availability 121 122 Index Index 125 Monitoring transaction service Session timeout 128