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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
The Informix® Administrator's Guide provides the information required to administer HCL Informix.
Disk, memory, and process management
Manage disk space
You can use several utilities and tools to manage disk spaces and the data that the database server controls.
Storage optimization
Data compression and consolidation processes can minimize the disk space that is used by your data and indexes.
Compression
You can compress and uncompress row data in tables and fragments and simple large objects in dbspaces. You can compress B-tree indexes. You can also consolidate free space in a table or fragment and you can return this free space to the dbspace. Before you compress data, you can estimate the amount of disk space that you can save.

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 Informix® Administrator's Guide provides 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.
      - 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.
        Allocate disk space
        This section explains how to allocate disk space for the database server.
        Specify names for storage spaces and chunks
        Chunk names follow the same rules as storage-space names.
        Monitor storage spaces
        You can monitor the status of storage spaces and configure how you are notified when a storage space becomes full.
        Manage dbspaces
        This section contains information about creating standard and temporary dbspaces with and without the default page size, specifying the first and next extent sizes for the tblspace tblspace in a dbspace when you create the dbspace, and adding a chunk to a dbspace or blobspace.
        Manage blobspaces
        This section explains how to create a blobspace and determine the blobpage size.
        Manage sbspaces
        This section describes how to create a standard or temporary sbspace, monitor the metadata and user-data areas, add a chunk to an sbspace, and alter storage characteristics of smart large objects.
        Manage the plogspace
        You create or move the plogspace with the onspaces utility or equivalent SQL administration API command.
        Automatic space management
        You can configure the server to add more storage space automatically when more space is required. You use space more effectively and ensure that space is allocated as necessary, while reducing out-of-space errors. You reduce the time required to manually monitor your spaces to determine which storage space might run out of free space. If you configure the server to automatically add space, you can also manually expand a space or extend a chunk.
        Drop a chunk
        Use the onspaces utility to drop a chunk from a dbspace.
        Drop a storage space
        Use onspaces to drop a dbspace, temporary dbspace, blobspace, sbspace, temporary sbspace, or extspace.
        Creating a space or chunk from the storage pool
        If your storage pool contains entries, you can create storage spaces or chunks from free space in the storage pool.
        Returning empty space to the storage pool
        You can return the space from an empty chunk or storage space to the storage pool.
        Manage extspaces
        Skip inaccessible fragments
        Display databases
        You can display the databases that you create with SMI tables.
        Monitor disk usage
        Multitenancy
        You can segregate data, storage space, and processing resources for multiple client organizations by creating multiple tenant databases in a single instance of Informix®.
        Storage optimization
        Data compression and consolidation processes can minimize the disk space that is used by your data and indexes.
        Storage optimization methods
        You can optimize individual tables, fragments, or indexes. You can schedule the automatic optimization of all tables and fragments.
        Scheduling data optimization
        You can configure the automatic compressing, shrinking, repacking, and defragmenting of all tables and extents by enabling the auto_crsd Scheduler task.
        Example: Optimizing data storage on demand
        In this example, you learn how to run SQL administration API commands to determine how much space you can save by compressing a table, how to compress the table, and how to optimize storage on demand. You also learn how to uncompress the table and remove the compression dictionaries.
        Partition defragmentation
        You can improve performance by defragmenting partitions to merge non-contiguous extents.
        Compression
        You can compress and uncompress row data in tables and fragments and simple large objects in dbspaces. You can compress B-tree indexes. You can also consolidate free space in a table or fragment and you can return this free space to the dbspace. Before you compress data, you can estimate the amount of disk space that you can save.
        Data that you can compress
        You can compress data in rows and simple large objects in dbspaces. However, you might not want to compress all the types of data that you can compress.
        Data that you cannot compress
        You cannot compress data in rows in some types of tables and fragments.
        B-tree index compression
        You can compress detached B-tree indexes. You can also consolidate free space in the index and you can return free space at the end of the index to the dbspace. Before you compress an index, you can estimate the amount of disk space that you can save.
        Compression ratio estimates
        The compression ratio depends on the data that is being compressed. Before you compress a table or table fragment, you can estimate the amount of space you can save if data is compressed. Compression estimates are based on samples of row data. The actual ratio of saved space might vary.
        Compression dictionaries
        A compression dictionary is a library of frequently occurring patterns in data or index keys and the symbol numbers that replace the patterns.
        Tools for moving compressed data
        You can use HCL Informix® data migration utilities to move compressed data between databases.
        BLOBspace Blob Compression
        A partition BLOB (binary large object) column is a TEXT or BYTE column that is stored in a DBspace, in the same RSAM partition as the home row. A BLOBspace BLOB column is the same data type (TEXT or BYTE), but the BLOB data is stored in a BLOBspace.
        Methods for viewing compression information
        You can display compression statistics, information about compression dictionaries, and the compression dictionary.
        Load data into a table
      - 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.
  - Administrator's Reference
    The 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 Informix® DB-Access User's Guide describes how to use the DB-Access utility to access, modify, and retrieve information from 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 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.
  - 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.
  - 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
  The Informix® Backup and Restore Guide describes how to use the 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
  The HCL® Informix® Enterprise Replication Guide describes the concepts of data replication using Informix Enterprise Replication, including how to design your replication system, as well as administer and manage data replication throughout your enterprise.

Compression

You can compress and uncompress row data in tables and fragments and simple large objects in dbspaces. You can compress B-tree indexes. You can also consolidate free space in a table or fragment and you can return this free space to the dbspace. Before you compress data, you can estimate the amount of disk space that you can save.

Compressing data, simple large objects, or indexes, consolidating data, and returning free space have the following benefits:

Significant savings in disk storage space
Reduced disk usage for compressed fragments
Significant saving of logical log usage, which saves more space and can prevent bottlenecks for high-throughput OLTP after the compression operation is completed.
Fewer page reads because more rows can fit on a page
Smaller buffer pools because more data fits in the same size pool
Reduced I/O activity:
- More compressed rows than uncompressed rows fit on a page
- Log records for insert, update, and delete operations of compressed rows are smaller
Ability to compress older fragments of time-fragmented data that are not often accessed, while leaving more recent data that is frequently accessed in uncompressed form
Ability to free space no longer required for a table
Faster backup and restore

If your applications run with high buffer cache hit ratios and high performance is more important than space usage, you might not want to compress your data, because compression might slightly decrease performance.

You can compress data and indexes in parallel.

Queries can access data in a compressed table.

Because compressed data covers fewer pages and has more rows per page than uncompressed data, the query optimizer might choose different plans after compression.

If you use Enterprise Replication, compressing data on one replication server does not affect the data on any other replication server.

If you use high-availability clusters, data that is compressed in the source table is compressed in the target table. You cannot perform compression operations on secondary servers, because secondary servers must have the same data and physical layout as the primary server.

The main alternative to compression is to buy more physical storage. The main alternative for reducing bottlenecks in IO-bound workloads is to buy more physical memory to enable the expansion of the buffer pools.