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--- tips:revmedia:v3i2a1 [2023/11/20 14:55] – bshumsky
+++ tips:revmedia:v3i2a1 [2024/06/19 20:20] (current) – external edit 127.0.0.1
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+====== Index Flush=====
+^Published By^Date^Version^Knowledge Level^Keywords^
+|Sprezzatura Ltd|01 JUN 1991|2.03+|EXPERT|INDEX.FLUSH, FILE.DISTRIBUTOR, INDEX, !INDEXING, FLUSH|
+The ability to update indexes from within a program is provided by a system
+subroutine called INDEX.FLUSH. This routine takes two parameters, the file
+information and the index information. Using this routine, it is possible to
+update
+  * All indexes: Pass "",""
+  * All indexes for a file: Pass File_Info,""
+  * An  index for a file: Pass File_Info,Index_Info
+There have been reports that this routine does not work as documented but
+this appears to stem from a misunderstanding of how the routine works.
+Regardless of how the routine is called, the same system routine
+(FILE.DISTRIBUTOR) is called to clear !INDEXING. This routine does not check
+to see which index it has been asked to distribute to the ! files, it just
+moves all transaction records to the appropriate ! files clearing down
+!INDEXING as it does so. Thus regardless of which mode is used, the
+!INDEXING file will always be clear (assuming all relevant files are
+attached) after an INDEX.FLUSH call. If a request was made to update a
+specific file, all other ! files would have transactions left pending in
+records 0, 1, 2 etc. If a request was made to update a specific index, all
+other ! files would have transactions left pending in records 0, 1, 2 etc
+and the main ! file would have other index transactions pending in records
+, 1, 2 etc.
+Note that because of this if there are a large amount of index transactions
+pending, there can be a considerable delay when INDEX.FLUSH is called even
+if none of the pending transactions are for the nominated file/index.
+Contrary to the documentation it is possible to just pass the name of a file
+to INDEX.FLUSH (rather than the complete FILE*ACCOUNT*MEDIA_NAME), and it
+will then resolve the rest of the information itself. This removes the need
+for additional code at the application level. It is however important to
+ensure that the file you wish to flush with this command is the currently
+attached one.
+(Volume 3, Issue 2, Page 4)