Welcome
Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
System administration
These topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL Informix® database servers.
Performance Guide
The HCL® Informix® Performance Guide describes how to configure and operate your HCL Informix database server to improve overall system throughput and to improve the performance of SQL queries.
Table performance considerations
Some performance issues are associated with unfragmented tables and table fragments.
Placing tables on disk
Tables that the database server supports reside on one or more portions of one or more disks. You control the placement of a table on disk when you create it by assigning it to a dbspace.
Using multiple disks
You can use multiple disks for dbspaces, logical logs, temporary tables, and sort files.
Spreading temporary tables and sort files across multiple disks
You can spread the I/O associated with temporary tables and sort files across multiple disks, after defining dbspaces for temporary tables and sort files. This can improve performance for applications that require a large amount of temporary space for temporary tables or large sort operations.

HCL Informix® V15.0.0 documentation
Welcome to the documentation for HCL Informix® 15.0.0 and related client tools and products.
Product overview
HCL Informix® is a fast and scalable database server that manages traditional relational, object-relational, and dimensional databases. Its small footprint and self-managing capabilities are suited to embedded data-management solutions.
Installing
These topics describe how to install HCL Informix® database servers, client products, and modules.
Administering
In addition to administering the database server, you can tune performance, replicate data, and archive data.
- System administration
  These topics contain concepts, procedures, and reference information for database and database server administrators to use for managing and tuning HCL Informix® database servers.
  - List of utilities
    HCL Informix® includes utilities and applications that you can use to perform administrative tasks and capture information about configuration and performance.
  - Administrator's Guide
    The HCL® Informix® Administrator's Guide provides the information required to administer HCL Informix.
  - Administrator's Reference
    The HCL® Informix® Administrator's Reference includes comprehensive descriptions of HCL Informix 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 Guide
    The HCL® Informix® DB-Access User's Guide describes how to use the utility to access, modify, and retrieve information from HCL Informix database servers.
  - High-Performance Loader User's Guide
    The describes how to use the HCL Informix® to load and unload large quantities of data efficiently to or from Informix databases.
  - Performance Guide
    The HCL® Informix® Performance Guide describes how to configure and operate your HCL Informix database server to improve overall system throughput and to improve the performance of SQL queries.
    - Performance basics
      Performance measurement and tuning issues and methods are relevant to daily database server administration and query execution.
    - Performance monitoring and the tools you use
      You 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 utilization
      The combination of operating-system and Informix® configuration parameters can affect CPU utilization. You can change the settings of the Informix configuration parameters that directly affect CPU utilization, and you can adjust the settings for different types of workloads.
    - Effect of configuration on memory utilization
      The combination of operating-system and Informix® configuration parameters can affect memory utilization.
    - Table performance considerations
      Some performance issues are associated with unfragmented tables and table fragments.
      - Placing tables on disk
        Tables that the database server supports reside on one or more portions of one or more disks. You control the placement of a table on disk when you create it by assigning it to a dbspace.
        Isolating high-use tables
        You can place a table with high I/O activity on a dedicated disk device. Doing this reduces contention for the data that is stored in that table.
        Placing high-use tables on middle partitions of disks
        To minimize disk-head movement, place the most frequently accessed data on partitions close to the middle band of the disk (not near the center and not near the edge). This approach minimizes disk-head movement to reach data in the high-demand table.
        Using multiple disks
        You can use multiple disks for dbspaces, logical logs, temporary tables, and sort files.
        Using multiple disks for a dbspace
        Using multiple disks for a dbspace helps to distribute I/O across dbspaces that contain several small tables.
        Using multiple disks for logical logs
        You can distribute logical logs in different dbspaces on multiple disks in round-robin fashion to improve logical backup performance. This scheme allows the database server to back up logs on one disk, while performing logging operations on the other disks.
        Spreading temporary tables and sort files across multiple disks
        You can spread the I/O associated with temporary tables and sort files across multiple disks, after defining dbspaces for temporary tables and sort files. This can improve performance for applications that require a large amount of temporary space for temporary tables or large sort operations.
        Backup and restore considerations when placing tables on disks
        When you decide where to place your tables or fragments, remember that if a device that contains a dbspace fails, all tables or table fragments in that dbspace are rendered inaccessible, even though tables and fragments in other dbspaces are accessible. The need to limit data unavailability in the event of a disk failure might influence which tables you group together in a particular dbspace.
        Factors affecting the performance of nonfragmented tables and table fragments
        Numerous factors affect the performance of an individual table or table fragment. These include the placement of the table or fragment, the size of the table or fragment, the indexing strategy that was used, the size and placement of table extents with respect to one another, and the frequency of access to the table.
      - Estimating table size
        You can calculate the approximate sizes (in disk pages) of tables.
      - Managing the size of first and next extents for the tblspace tblspace
        The tblspace tblspace is a collection of pages that describe the location and structure of all tblspaces in a dbspace. Each dbspace has one tblspace tblspace. When you create a dbspace, you can use the TBLTBLFIRST and TBLTBLNEXT configuration parameters to specify the first and next extent sizes for the tblspace tblspace in a root dbspace.
      - Managing sbspaces
        An sbspace is a logical storage unit composed of one or more chunks that store smart large objects. You can estimate the amount of storage needed for smart large objects, improve metadata I/O, monitor sbspaces, and change storage characteristics.
      - Managing extents
        As you add rows to a table, the database server allocates disk space in units called extents. Each extent is a block of physically contiguous pages from the dbspace. Even when the dbspace includes more than one chunk, each extent is allocated entirely within a single chunk, so that it remains contiguous.
      - Storing multiple table fragments in a single dbspace
        You can store multiple fragments of the same table or index in a single dbspace, thus reducing the total number of dbspaces needed for a fragmented table. You must specify a name for each fragment that you want to store in the same dbspace. Storing multiple table or index fragments in a single dbspace simplifies the management of dbspaces.
      - Displaying a list of table and index partitions
        Use the onstat -g opn option to display a list of the table and index partitions, by thread ID, that are currently open in the system.
      - Changing tables to improve performance
        You can change tables to improve performance by dropping indexes, attaching or detaching fragments, and altering table definitions. You can also create databases for decision-support applications by unloading and loading tables in OLTP databases.
      - Denormalize the data model to improve performance
        You might need to denormalize the data model to reduce overhead and optimize performance.
      - Reduce disk space in tables with variable length rows
        You can enable the database server to insert more rows per page into tables with variable-length rows, if you set the MAX_FILL_DATA_PAGES configuration parameter to 1. Allowing more variable length rows per page has advantages and disadvantages.
      - Reduce disk space by compressing tables and fragments
        You can reduce disk space by compressing data in tables and table fragments. After compressing data, you can repack the data to consolidate the free space in a table or fragment, and shrink the space for the data to return the free space to the dbspace.
    - Boosted Partition Free Space Caches (PFSC)
    - Indexes and index performance considerations
      Informix® provides several types of indexes. Some performance issues are associated with indexes.
    - Locking
      The database server uses locks, which can affect concurrency and performance. You can monitor and administer locks.
    - Fragmentation guidelines
      One 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 optimizer
      These 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 directives
      Optimizer 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 performance
      You can test, monitor, and improve queries.
    - Appendix
  - SNMP Subagent Guide
    The describes the Simple Network Management Protocol (SNMP) and the software that you need to use SNMP to monitor and manage HCL Informix® database servers and databases.
- Backup and Restore Guide
  The HCL® Informix® Backup and Restore Guide describes how to use the HCL Informix and ontape utilities to back up and restore database server data. These utilities enable you to recover your databases after data is lost or becomes corrupted due to hardware or software failure or accident.
- Enterprise Replication
  The describes the concepts of data replication using HCL Informix® Enterprise Replication, including how to design your replication system, as well as administer and manage data replication throughout your enterprise.
Migrating and upgrading
You can upgrade to the 15.0.0 release of HCL Informix® or migrate from other database servers to Informix. Upgrading is an in-place migration method that uses your existing hardware and operating system software. Some changes to the Informix database server can affect upgrading from a previous release.
Client APIs and tools
You can use the HCL Informix® implementation of client APIs to develop applications for Informix database servers.
Embedding Informix®
When you embed HCL Informix®, you can use enterprise-class high-availability and high performance with embeddability features such as easy programmability, a small disk and memory footprint, and silent deployment.
Extending Informix®
Beyond standard relational database objects, HCL Informix® can be extended to handle specialized data types, access methods, routines, and other objects. Informix includes many built-in extensions that are fully integrated in the database server. Informix also provides modules, which are packages of extended database objects for a particular purpose and that are installed separately from the database server. Alternatively, you can create your own user-defined objects for Informix.
Data warehousing
In addition to designing and implementing Informix® dimensional databases, you can use tools to create data warehouse applications and optimize your data warehouse queries.
Designing databases
The first step in creating a relational database is to construct a data model, which is a precise, complete definition of the data you want to store. After you prepare your data model, you must implement it as a database and tables. To implement your data model, you first select a data type for each column and then you create a database and tables and populate the tables with data. You can also implement fragmentation strategies and control access to your data.
JSON compatibility
You can use the popular JSON-oriented query language created by MongoDB to interact with data stored in HCL Informix®.
Security
You can secure your Informix® database server and the data that is stored in your Informix databases. You can encrypt data, secure connections, control user privileges and access, and audit data security.
SQL programming
You can use the HCL Informix® implementation of the SQL language to develop applications for Informix database servers.
Troubleshooting HCL Informix®
Several troubleshooting techniques, tools, and resources are available for resolving problems that you encounter in your HCL Informix® database server environment.

Spreading temporary tables and sort files across multiple disks

You can spread the I/O associated with temporary tables and sort files across multiple disks, after defining dbspaces for temporary tables and sort files. This can improve performance for applications that require a large amount of temporary space for temporary tables or large sort operations.

To define several dbspaces for temporary tables and sort files, use onspaces -t. When you place these dbspaces on different disks and list them in the DBSPACETEMP configuration parameter, you spread the I/O associated with temporary tables and sort files across multiple disks, as Dbspaces for temporary tables and sort files illustrates. You can list dbspaces that contain regular tables in DBSPACETEMP.

This figure is described in the surrounding text. — Figure 1. Dbspaces for temporary tables and sort files

Users can specify their own lists of dbspaces for temporary tables and sort files with the DBSPACETEMP environment variable. For details, see Configure dbspaces for temporary tables and sort files.