>That's great thanks for the info.
>
>A couple of other questions, if you have the time to answer :
>a) are there any tools available for checking indexes. It would be nice to confirm that any odd behaviour is due to index corruption, prior to reindexing.
>b) Does reindexing have any impact on performance ? At this point, the tables I am using are relatively small & so it is difficult to determine if there is any effect, just thought you might have some idea on this.

Using REINDEX, rather than using DELETE TAG ALL followed by rebuilding the indexes from scratch ,will generally leave the CDX files with wasted space that is not easily recovered, and does not optimize the positioning of segments of multiple tags within the CDX - parts of a given tag are likely to be spread broadly throughout the file, rather than being immediately adjacent to other related tag segments, which requires more disk head movement when processing a tag. Generally, deleting all tags, defragmenting the disk, and then rebiuilding the CDX from scratch will create a smaller CDX file, and often improves performance involving use of an index, especially with large files that add records or change key values frequently. Defragmentation of the drive helps ensure that related segments are together, letting the OS take advantage of readahead andreducing seek times.