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- Use conditions
- Automatic reindexing
- "Zero-downtime" reindexing
- Calculating statistics
- Directory of temporary files
- Managing non-Latin character sets
- Access rights to the data file
- Special case: Data files corrupted after a reboot or a fatal error
- Previous versions
HIndex (Function) In french: HRéindexe
  Available only with these kinds of connection
Rebuilds the file index (".NDX" file). You can also reindex: - full-text indexes (".FTX" files),
- spatial indexes (".SDX" files).
A data file can be reindexed even when it is accessed by one or more applications. For more details, see remarks.  Subscription-exclusive new featureReminder: Reindexing reorganizes indexes and can free up space left when records are deleted. After reindexing, the access to indexes is optimized. Reindexing a data file can become necessary further to the loss or modification of the index file. HCheckIndex is used to regularly check the status of the index file.
IF HIndex(AFile, hNdxNormal) = True THEN
TableDisplay(TABLE_MyTable, taStart)
END
Syntax
<Result> = HIndex([<Data file> [, <Mode> [, <Progress Bar> [, <Density rate>]]]])
<Result>: Boolean - True if the reindex operation was successfully performed,
- False otherwise. HError returns more details about the problem.
<Data file>: Optional character string Name of the data file used.
If this name is not specified, HIndex will use the last data file used by the last HFSQL function (function starting with "H"). <Mode>: Optional Integer constant (or combination of constants) Reindexing configuration: | | | hChangeCharset | Reindexing with change of character set.
The new character set defined by ChangeCharset will be taken into account during the reindexing. Sorts, searches or other types of operations performed on string keys (strings, characters, date and time) will use the new character set. | | hFTX | Reindexing of full-text indexes. | | hMmoCompact | Compression and defragmentation of "Mmo" files.
Caution: This constant cannot be combined with the hNdxCompact, hCheckMemo, hFTX, hSDX, hNdxNormal or hNdxDelete constants. | | hNdxCompact | Reindexing with compression: Only active records are preserved. All the other records are permanently deleted. The space left by the deleted records is deleted from the data file and the index (".FIC" and ".NDX" files, respectively).
Note: If one or more records are in a transaction, compression is automatically disabled. | | hNdxMinimal | Reindexing while taking into account only corrupted keys. This parameter is ignored if the hNdxDelete or hNdxCompact constant are enabled. | | hNdxSilent | Reindexing without display. | hNdxNormal
(default value) | Standard reindexing (with statistics and without compression).
Statistics help optimize queries and filters (see the Notes). Only active records are taken into account for calculating statistics. | | hNdxNoStat | Reindexing without calculating statistics. This constant saves space by reducing the index file size.
Note: Statistics are important to achieve acceptable execution times when using queries, conditional filters and views with conditions. | | hNdxDelete | Reindex and delete damaged records. | | hSDX | Reindexing of spatial indexes. | | hBackgroundTask | | | hCheckMemo | Standard reindexing with verification of Memo items and correction if necessary (can be used to retrieve damaged memos). |
<Progress Bar>: Optional control or window name, or optional integer - Name of the window in which the progress bar will be displayed,
- Name of the Progress Bar control that displays the reindexing progress,
- Handle of the window that displays the progress bar.
<Density rate>: Integer between 1 and 100 Density rate of indexes. This rate is set to 60 by default.
The higher this rate is, the denser and smaller the index is. In this case, iterations, searches, filters and queries will be faster. Adding and modifying records may take longer.
The smallest this rate is, the less dense and the bigger the index will be. In this case, iterations, searches, filters and queries will be slower. Adding and modifying records will be faster.
Caution: This parameter can only be used on HFSQL data files..
Remarks Use conditions - HIndex reindexes an xBase file.
- HIndex is used to reindex data files in a cluster. In this case:
- Reindexing is performed on the node to which the user is connected.
- Only zero-downtime reindexing is available (hBackgroundTask constant).
Calculating statistics Statistics help optimize queries and filters in the data file. Only active records are taken into account for calculating statistics. HStatCalculate also returns the results of this calculation. Note: For optimal results, this calculation must include all data files (e.g. multi-file query). Directory of temporary files Temporary files can be created during reindexing. By default, these files are created in the Windows temporary directory or in the current directory if there is not enough space. The H.TemporaryDirectory variable allows you to configure the directory used to save these temporary files. This variable is recommended when reindexing large data files.
Access rights to the data file Reindexing recreates the data file on disk. In an allocation system that manages permissions at file level (NTFS, etc.), the reindexed data file will have the permissions of the directory to which it belongs. If the data file had different rights from those of the folder before reindexing, you must redefine them in Windows after reindexing. Special case: Data files corrupted after a reboot or a fatal error Some data files may be corrupted when the computer reboots unexpectedly. In this case, the data files contain invalid data (unreadable characters for example). To fix this problem: - Perform a reindexing with deletion.
- Free all records held by a transaction with HTransactionFree.
- Delete the incorrect records with WDMAP.
Business / UI classification: Business Logic
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