Performance and administration

Sometimes not the big features make your day with Informix more productive and smoother. Often practical improvements come along  soft-footed and in a simple manner, wondering how easy things can be ... . In the following we would like to give you some recommendations for a more efficient handling of your  Informix 14.10 database:

  • DIRECT_IO: traditionally Informix works with Raw Devices. This means Informix communicates directly with the storage bypassing the operating system and the cache. Compared with “cooked files” this leads to a significantly better performance. Using DIRECT_IO  results in a comparable performance of “cooked files” and raw devices. DIRECT_IO has already been known for a couple of years in the Linux and Informix world. New: since Informix v14.10 DIRECT_IO is available for TempSpaces. Previously it was only possible to use it for “normal” DBspaces. Activation was enabled by the setting of specific parameters. 0 = disabled, 1 = enabled, 2 = for AIX file system. DIREC T_IO for TempSpaces is enabled with Flag 0x4 = Special I/O is enabled for TEMP DBSpaces. DIRECT _IO and RAW leads to similar results.
  • cdr_migrate_server: implementation of Enterprise Replication (CDR/ER) is time intensive and complex. Usually you need a lot of commands in the correct order. This includes the definition of the CDR server, the preparation of the replicates, to add the keys and the data transfer to the target server. With Informix 14.10 the Enterprise Replication is much more easier and faster. All required commands can be prepared automatically by "cdr migrate server" and are executed in the correct order from the source server by usage of a syntax including all relevant steps. You need just one command line in order to display and execute all necessary commands. Additionally it is possible to exclude tables from the replication. Furthermore you can add the option "add_replcheck". In this case the data on the target and source side are checked. If there are differences the missing data can be added. The precondition for the usage of „cdr_migrate_server“ are the existence of Storage pools on both sides (target/source), the mutual availability of both servers and the registration of both instances in INFORMIXDIR. Please note: the source server has to be Informix 11.70xC1 at minimum! Due to the performance benefits of „cdr_migrate_server“ it is useful when performing database and/or operating system updates/upgrades or implementing a Desaster Recovery.
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