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
These topics describe how to configure and operate your HCL Informix® database server to improve overall system throughput and to improve the performance of SQL queries.
Effect of configuration on I/O activity
The configuration of your database server affects I/O activity.
I/O for cooked files for dbspace chunks
On UNIX™, you can control the use of direct I/O for cooked files used for dbspace chunks.
Direct I/O (Windows™)
Direct I/O is used for dbspace chunks on Windows™ platforms regardless of the value of the DIRECT_IO configuration parameter.

HCL Informix® V15.0 documentation
Welcome to the documentation for HCL Informix® 15.0 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 DataBlade® 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
    These topics provide the information required to administer HCL Informix®.
  - Administrator's Reference
    These topics include 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
    This publication describes how to use the DB-Access utility to access, modify, and retrieve information from HCL® Informix® database servers.
  - High-Performance Loader User's Guide
    These topics describe how to use the HCL Informix® High-Performance Loader (HPL) to load and unload large quantities of data efficiently to or from Informix databases.
  - Performance Guide
    These topics describe 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.
    - Effect of configuration on I/O activity
      The configuration of your database server affects I/O activity.
      - Chunk and dbspace configuration
        The 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 chunks
        On UNIX™, you can control the use of direct I/O for cooked files used for dbspace chunks.
        Direct I/O (UNIX)
        On UNIX™, you can use direct I/O to improve the performance of cooked files. Direct I/O can be beneficial because it avoids file system buffering. Because direct I/O uses unbuffered I/O, it is more efficient for reads and writes that go to disk (as opposed to those reads and writes that merely access the file system buffers).
        Direct I/O (Windows™)
        Direct I/O is used for dbspace chunks on Windows™ platforms regardless of the value of the DIRECT_IO configuration parameter.
        Concurrent I/O (AIX only)
        On AIX® operating systems, you can use concurrent I/O in addition to direct I/O for chunks that use cooked files. Concurrent I/O can improve performance, because it allows multiple reads and writes to a file to occur concurrently, without the usual serialization of noncompeting read and write operations.
        Enabling the direct I/O or concurrent I/O option (UNIX™)
        Use the DIRECT_IO configuration parameter to enable the direct I/O option on UNIX™ or the concurrent I/O option on AIX®.
        Confirming the use of the direct or concurrent I/O option (UNIX™)
        You can confirm and monitor the use of direct I/O or concurrent I/O (on AIX®) for cooked file chunks.
      - Placement of critical data
        The 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 data
        The configuration parameters that configure the root dbspace and the logical and physical logs affect critical data.
      - Configure dbspaces for temporary tables and sort files
        Applications 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 objects
        Applications 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 objects
        You 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 objects
        An 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.
      - How the Optical Subsystem affects performance
        The 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 Subsystem
        The STAGEBLOB and OPCACHEMAX configuration parameters and the INFORMIXOPCACHE environment variable affect the performance of the Optical Subsystem.
      - Table I/O
        One 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/O
        The 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 activities
        Background 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 considerations
      Some performance issues are associated with unfragmented tables and table fragments.
    - 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.
    - The onperf utility on UNIX
      The 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
  - SNMP Subagent Guide
    These topics describe 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.
  - InformixHQ Guide
    InformixHQ is a modern web console for visualizing, monitoring, and managing your Informix 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 Informix 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 Informix database server instances. InformixHQ is designed to be scalable to efficiently manage and monitor as many Informix 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. InformixHQ is the centralized hub for graphical monitoring, alerting, and administration of your Informix database servers.
- Backup and Restore Guide
  These topics describe how to use the HCL® Informix® ON-Bar 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
  These topics describe 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 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 DataBlade® 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.

Direct I/O (Windows™)

Direct I/O is used for dbspace chunks on Windows™ platforms regardless of the value of the DIRECT_IO configuration parameter.