REVMEDIA FKB Articles - AREV, OI, REV G, jREV, JCDC, LIVEWATER,ADVANCED REVELATION, OPENINSIGHT, REVELATION G

RevMedia FKB

Document	V3I9A5
Title	Batch.Indexing
Keywords	BATCH.INDEXING
Text	BATCH INDEXING is a routine which permits the buffering of index transactions in memory until certain pre set limits are reached USING this routine speed improvements of 30%+ are typical The usage is simple just call BATCH INDEXING(1 File_Var) to turn batching on and BATCH INDEXING(0 File_Var) to turn it off From thereon index transactions are buffered in memory for that file and not actually written to the ! datafile The pre set limits are documented in the latest "System Subroutines" book FROM Revelation Technologies as follows "BATCH INDEXING either BUFFERS a set amount of data (1 000 bytes) or buffers for a limited time (5 seconds) whichever occurs first so you need not be concerned WITH overrunning memory space" Caveats The information buffered by BATCH INDEXING is only flushed to disk by the ! code and by a DIRECT call to BATCH INDEXING turning the buffering off Further only one file is buffered at a time This has four major implications ; You should NEVER logoff without first turning BATCH INDEXING off If you do any buffered transactions will be lost (Fixed in 2 12) The time between flushes is only 5 seconds if records are continually being written to disk through the ! code That is if a record is written to disk and then the machine is left standing for 24 hours the buffered TRANSACTION will still be in memory However the moment a record is written to the same file the record will be flushed Neither INDEX FLUSH nor background indexing flush the buffered transactions to disk regardless of the "Delay before indexing" settings If BATCH INDEXING is started on one file and transactions are buffered and then BATCH INDEXING is started on a new file the old transactions will be written to the new file (Volume 3 Issue 9 Pages 5 6)

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