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.
Indexes and index performance considerations
Informix® provides several types of indexes. Some performance issues are associated with indexes.
Indexes on user-defined data types
You can define your own data types and the functions that operate on these data types. You can define indexes on some kinds of user-defined data types.
Using an index that a module provides
modules can provide new data types that users can access. A module can also provide a new index for the new data type.

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.
    - Boosted Partition Free Space Caches (PFSC)
    - Indexes and index performance considerations
      Informix® provides several types of indexes. Some performance issues are associated with indexes.
      - Types of indexes
        Informix® uses B-tree indexes, R-tree indexes, functional indexes, and indexes that modules provide for user-defined data. The server also uses forest of trees (FOT) indexes, which are alternatives to B-tree indexes.
      - Estimating index pages
        The index pages associated with a table can add significantly to the size of a dbspace.
      - Managing indexes
        An index on the appropriate column can save thousands, tens of thousands, or in extreme cases, even millions of disk operations during a query. However, indexes entail costs.
      - Improve query performance with a forest of trees index
        A forest of trees index is an alternate indexing method that alleviates the performance bottlenecks and root node contention that can occur when many concurrent users access a traditional B-tree index.
      - Creating and dropping an index in an online environment
        You can use the CREATE INDEX ONLINE and DROP INDEX ONLINE statements to create and drop an index in an online environment, when the database and its associated tables are continuously available.
      - Improving performance for index builds
        You can improve performance for index builds by adjusting the PDQ priority and by allocating enough memory and temporary space for the entire index.
      - Storing multiple index fragments in a single dbspace
        You can store multiple fragments of the same index in a single dbspace, 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 index fragments in a single dbspace simplifies the management of dbspaces.
      - Improving performance for index checks
        The oncheck utility provides better concurrency for tables that use row locking. When a table uses page locking, oncheck places a shared lock on the table when it performs index checks. Shared locks do not allow other users to perform updates, inserts, or deletes on the table while oncheck checks or prints the index information.
      - Indexes on user-defined data types
        You can define your own data types and the functions that operate on these data types. You can define indexes on some kinds of user-defined data types.
        Defining indexes for user-defined data types
        As with built-in data types, you might improve the response time for a query when you define indexes for new data types.
        Using an index that a module provides
        modules can provide new data types that users can access. A module can also provide a new index for the new data type.
        Choosing operator classes for indexes
        For most situations, use the default operators that are defined for a secondary-access method. However, when you want to order the data in a different sequence or provide index support for a user-defined data type, you must extend an operator class.
    - 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.

Using an index that a module provides

modules can provide new data types that users can access. A module can also provide a new index for the new data type.

For more information about the types of data and functions that each module provides, see the user guide for the module. For information about how to determine the types of indexes available in your database, see Identifying the available access methods.