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.
Administrator's Guide
These topics provide the information required to administer HCL Informix®.
Disk, memory, and process management
Virtual processors and threads
These topics describe virtual processors, explain how threads run within the virtual processors, and explain how the database server uses virtual processors and threads to improve performance.
Virtual processor classes
Each class of virtual processor is dedicated to processing certain types of threads.
CPU virtual processors
The CPU virtual processor runs all session threads (the threads that process requests from SQL client applications) and some internal threads.
Add and drop CPU virtual processors in online mode
You can add or drop CPU class virtual processors while the database server is online.

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 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®.
    - The database server
    - Disk, memory, and process management
      - Virtual processors and threads
        These topics describe virtual processors, explain how threads run within the virtual processors, and explain how the database server uses virtual processors and threads to improve performance.
        Virtual processors
        A virtual processor is a process that the operating system schedules for processing.
        How virtual processors service threads
        A virtual processor services multiple threads concurrently by switching between them.
        Virtual processor classes
        Each class of virtual processor is dedicated to processing certain types of threads.
        CPU virtual processors
        The CPU virtual processor runs all session threads (the threads that process requests from SQL client applications) and some internal threads.
        Determine the number of CPU virtual processors needed
        The right number of CPU virtual processors is the number at which they are all kept busy but not so busy that they cannot keep pace with incoming requests. You must not allocate more CPU virtual processors than the number of hardware processors in the computer.
        Run on a multiprocessor computer
        If you are running multiple CPU virtual processors on a multiprocessor computer, set the MULTIPROCESSOR parameter in the onconfig file to 1.
        Run on a single-processor computer
        If you are running the database server on a single-processor computer, set the MULTIPROCESSOR configuration parameter to 0. To run the database server with only one CPU virtual processor, set the SINGLE_CPU_VP parameter to 1.
        Add and drop CPU virtual processors in online mode
        You can add or drop CPU class virtual processors while the database server is online.
        Prevent priority aging
        Some operating systems lower the priority of long-running processes as they accumulate processing time, a feature of the operating system known as priority aging.
        Processor affinity
        The database server supports automatic binding of CPU virtual processors to processors on multiprocessor computers that support processor affinity.
        User-defined classes of virtual processors
        You can define special classes of virtual processors to run user-defined routines or to run a DataBlade® module.
        Tenant virtual processor class
        Tenant virtual processor classes are specific to tenant databases. If you configure multitenancy for your Informix® instance, you can specify that session threads for tenant databases are run in tenant virtual processors instead of CPU virtual processors.
        Java™ virtual processors
        Java™ UDRs and Java applications run on specialized virtual processors, called Java virtual processors (JVPs).
        Disk I/O virtual processors
        The following classes of virtual processors perform disk I/O: PIO (physical-log I/O), LIO (logical-log I/O), AIO (asynchronous I/O), and CPU (kernel-asynchronous I/O).
        Network virtual processors
        A client can connect to the database server in the through following ways: a network connection, a pipe, or shared memory.
        Communications support module virtual processor
        The communications support module (CSM) class of virtual processors performs communications support service and communications support module functions.
        Encrypt virtual processors
        Use the VPCLASS configuration parameter with the encrypt keyword to configure encryption VPs.
        Optical virtual processor
        The optical class (OPT) of virtual processors is used only with the Optical Subsystem.
        Audit virtual processor
        The database server starts one virtual processor in the audit class (ADT) when you turn on audit mode by setting the ADTMODE parameter in the onconfig file to 1.
        Miscellaneous virtual processor
        The miscellaneous virtual processor services requests for system calls that might require a very large stack, such as fetching information about the current user or the host-system name.
        Basic text search virtual processors
        A basic text search virtual processor is required to run basic text search queries.
        MQ messaging virtual processor
        An MQ virtual processor is required to use MQ messaging.
        Web feature service virtual processor
        A web feature service virtual processor is required to use web feature service for geospatial data.
        XML virtual processor
        An XML virtual processor is required to perform XML publishing.
      - Manage virtual processors
        These topics describe how to set the configuration parameters that affect database server virtual processors, and how to start and stop virtual processors.
      - Shared memory
        These topics describe the content of database server shared memory, the factors that determine the sizes of shared-memory areas, and how data moves into and out of shared memory.
      - Manage shared memory
      - Data storage
        The database server uses physical units of storage to allocate disk space. It stores data in logical units. Unlike the logical units of storage whose size fluctuates, each of the physical units has a fixed or assigned size that is determined by the disk architecture.
      - Manage disk space
        You can use several utilities and tools to manage disk spaces and the data that the database server controls.
      - Moving data with external tables
        You can use external tables to load and unload database data.
      - Storage space encryption
        You can encrypt storage spaces (dbspaces, blobspaces and smart blobspaces) with Informix Dynamic Server. The data in encrypted storage spaces is unintelligible without the encryption key. Encrypting storage spaces is an effective way to protect sensitive information that is stored on disk.
    - Logging and log administration
    - Fault tolerance
    - High availability and scalability
      A successful production environment requires database systems that are always available, with minimal if any planned outages, and that can be scaled quickly and easily as business requirements change.
    - Distributed data
    - Overview of automatic monitoring and corrective actions
      You can use the SQL administration API, the Scheduler, and drill-down queries to manage automatic maintenance, monitoring, and administrative tasks.
    - HCL Informix® server licensing
  - 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.
  - 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 15.0.0 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. The resources that are external to the information center are marked as such.
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.
Informix PDF guides

Add and drop CPU virtual processors in online mode

You can add or drop CPU class virtual processors while the database server is online.

For instructions on how to add or drop CPU class virtual processors, see Add virtual processors in online mode and Drop CPU and user-defined virtual processors.