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HCL OneDB 2.0.1
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  2. AdministeringIn addition to administering the database server, you can tune performance, replicate data, and archive data.
  3. System administrationThese topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL OneDB™ database servers.
  4. Performance GuideThe HCL OneDB™ Performance Guide describes how to configure and operate your HCL OneDB™ database server to improve overall system throughput and to improve the performance of SQL queries.
  5. Effect of configuration on I/O activityThe configuration of your database server affects I/O activity.
  6. Factors that affect I/O for smart large objectsAn sbspace is a logical storage unit, composed of one or more chunks, in which you can store smart large objects (such as BLOB, CLOB, or multi representational data). Disk layout for sbspaces, the settings of certain configuration parameters, and some onspaces utility options affect I/O for smart large objects.
  7. onspaces options that affect sbspace I/OWhen you create an sbspace with the onspaces utility, you specify information that affects I/O performance. This information includes the size of extents, the buffering mode (and whether you want the server to use lightweight I/O), and logging.
  8. LoggingIf you decide to log all write operations on data stored in sbspaces, logical-log I/O activity and memory utilization increases.
  • AdministeringIn addition to administering the database server, you can tune performance, replicate data, and archive data.
    • System administrationThese topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL OneDB™ database servers.
      • Administrator's GuideThe HCL OneDB™ Administrator's Guide provides the information required to administer HCL OneDB™.
      • Administrator's ReferenceThe HCL OneDB™ Administrator's Reference includes comprehensive descriptions of HCL OneDB™ configuration parameters, the system-monitoring interface (SMI) tables in the sysmaster database, the syntax of database server utilities such as onmode and onstat, logical-log records, disk structures, event alarms, and unnumbered error messages.
      • DB-Access User's GuideThis publication describes how to use the DB-Access utility to access, modify, and retrieve information from HCL® OneDB® database servers.
      • Performance GuideThe HCL OneDB™ Performance Guide describes how to configure and operate your HCL OneDB™ database server to improve overall system throughput and to improve the performance of SQL queries.
        • Performance basicsPerformance measurement and tuning issues and methods are relevant to daily database server administration and query execution.
        • Performance monitoring and the tools you useYou can use performance monitoring tools to create a performance history, to monitor database resources at scheduled times, or to monitor ongoing transaction or query performance.
        • Effect of configuration on CPU utilizationThe combination of operating-system and HCL OneDB™ configuration parameters can affect CPU utilization. You can change the settings of the HCL OneDB™ configuration parameters that directly affect CPU utilization, and you can adjust the settings for different types of workloads.
        • Effect of configuration on memory utilizationThe combination of operating-system and HCL OneDB™ configuration parameters can affect memory utilization.
        • Effect of configuration on I/O activityThe configuration of your database server affects I/O activity.
          • Chunk and dbspace configurationThe number of disks that you use and the configuration of your chunks, dbspaces, and blobspaces affect the performance of your database server. You can improve performance by planning disk use and the configuration of chunks, dbspaces, and blobspaces.
          • I/O for cooked files for dbspace chunksOn UNIX™, you can control the use of direct I/O for cooked files used for dbspace chunks.
          • Placement of critical dataThe disk or disks that contain the system reserved pages, the physical log, and the dbspaces that contain the logical-log files are critical to the operation of the database server. The database server cannot operate if any of these elements becomes unavailable. By default, the database server places all three critical elements in the root dbspace.
          • Configuration parameters that affect critical dataThe configuration parameters that configure the root dbspace and the logical and physical logs affect critical data.
          • Configure dbspaces for temporary tables and sort filesApplications that use temporary tables or large sort operations require a large amount of temporary space. To improve performance of these applications, use the DBSPACETEMP configuration parameter or the DBSPACETEMP environment variable to designate one or more dbspaces for temporary tables and sort files.
          • Configure sbspaces for temporary smart large objectsApplications can use temporary smart large objects for text, image, or other user-defined data types that are only required during the life of the user session. These applications do not require logging of the temporary smart large objects. Logging adds I/O activity to the logical log and increases memory utilization.
          • Placement of simple large objectsYou can store simple large objects in either the same dbspace in which the table resides or in a blobspace.
          • Factors that affect I/O for smart large objectsAn sbspace is a logical storage unit, composed of one or more chunks, in which you can store smart large objects (such as BLOB, CLOB, or multi representational data). Disk layout for sbspaces, the settings of certain configuration parameters, and some onspaces utility options affect I/O for smart large objects.
            • Disk layout for sbspacesYou create sbspaces on separate disks from the table with which the data is associated. You can store smart large objects associated with different tables within the same sbspace. When you store smart large objects in an sbspace on a separate disk from the table with which it is associated, the database server provides some performance advantages.
            • Configuration parameters that affect sbspace I/OThe SBSPACENAME, BUFFERPOOL, and LOGBUFF configuration parameters affect the I/O performance of sbspaces.
            • onspaces options that affect sbspace I/OWhen you create an sbspace with the onspaces utility, you specify information that affects I/O performance. This information includes the size of extents, the buffering mode (and whether you want the server to use lightweight I/O), and logging.
              • Sbspace extentsAs you add smart large objects to a table, the database server allocates disk space to the sbspace in units called extents. Each extent is a block of physically contiguous pages from the sbspace.
              • Lightweight I/O for smart large objectsInstead of using the buffer pool, the administrator and programmer have the option to use lightweight I/O. Lightweight I/O operations use private buffers in the session pool of the virtual portion of shared memory.
              • LoggingIf you decide to log all write operations on data stored in sbspaces, logical-log I/O activity and memory utilization increases.
          • How the Optical Subsystem affects performanceThe Optical Subsystem extends the storage capabilities of the database server for simple large objects (TEXT or BYTE data) to write-once-read-many (WORM) optical subsystems. The database server uses a cache in memory to buffer initial TEXT or BYTE data pages requested from the Optical Subsystem.
          • Environment variables and configuration parameters for the Optical SubsystemThe STAGEBLOB and OPCACHEMAX configuration parameters and the INFORMIXOPCACHE environment variable affect the performance of the Optical Subsystem.
          • Table I/OOne of the most frequent functions that the database server performs is to bring data and index pages from disk into memory. Pages can be read individually for brief transactions and sequentially for some queries. You can configure the number of pages that the database server brings into memory, and you can configure the timing of I/O requests for sequential scans.
          • Configuration parameters that affect table I/OThe AUTO_READAHEAD configuration parameter changes the automatic read-ahead mode or disables automatic read-ahead for a query. In addition, the DATASKIP configuration parameter enables or disables data skipping.
          • Background I/O activitiesBackground I/O activities do not service SQL requests directly. Many of these activities are essential to maintain database consistency and other aspects of database server operation. However, they create overhead in the CPU and take up I/O bandwidth.
        • Table performance considerationsSome performance issues are associated with unfragmented tables and table fragments.
        • Indexes and index performance considerationsHCL OneDB™ provides several types of indexes. Some performance issues are associated with indexes.
        • LockingThe database server uses locks, which can affect concurrency and performance. You can monitor and administer locks.
        • Fragmentation guidelinesOne of the most frequent causes of poor performance in relational database systems is contention for data that resides on a single I/O device. Proper fragmentation of high-use tables can significantly reduce I/O contention. These topics discuss the performance considerations that are involved when you use table fragmentation.
        • Queries and the query optimizerThese topics describe query plans, explain how the database server manages query optimization, and discuss factors that you can use to influence the query plan. These topics also describe performance considerations for SPL routines, the UDR cache, and triggers.
        • Optimizer directivesOptimizer directives are comments that tell the query optimizer how to execute a query. You can use optimizer directives to improve query performance.
        • Parallel database query (PDQ)You can manage how the database server performs PDQ and you can monitor the resources that the database server uses for PDQ.
        • Improving individual query performanceYou can test, monitor, and improve queries.
        • The onperf utility on UNIXThe onperf utility is a windowing environment that you can use to monitor the database server performance. The onperf utility monitors the database server running on the UNIX™ operating system.
        • Appendix
      • OneDB ExploreOneDB Explore is a modern web console for visualizing, monitoring, and managing your OneDB server instances. It is purpose built for ease-of-use, scaling out, and optimizing DevOps needs. It provides critical performance management capabilities, monitoring how key performance metrics are changing over time and tracking how efficiently OneDB is running your workload even when you’ve stepped away from your screen. Its monitoring system feeds directly into a customizable alerting system so you can be immediately alerted via email, Twilio, or PagerDuty whenever an issue occurs on one of your OneDB database server instances. OneDB Explore is designed to be scalable to efficiently manage and monitor as many OneDB database server instances as you need. Moreover, it's a tool that can be shared by the DBAs, the app developers, the ops engineers, and management and accessed from any desktop, laptop, or mobile device. OneDB Explore is the centralized hub for graphical monitoring, alerting, and administration of your OneDB database servers.
    • Backup and Restore GuideThe HCL OneDB™ Backup and Restore Guide describes how to use the HCL® OneDB® ON-Bar utility to back up and restore database server data. This will enable you to recover your databases after data is lost or becomes corrupted due to hardware or software failure or accident.
    • Enterprise ReplicationThe HCL OneDB™ Enterprise Replication Guide describes the concepts of data replication using HCL® OneDB® Enterprise Replication, including how to design your replication system, as well as administer and manage data replication throughout your enterprise.

Logging

If you decide to log all write operations on data stored in sbspaces, logical-log I/O activity and memory utilization increases.

For more information, see Configuration parameters that affect sbspace I/O.

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