gpmenos@phoenix.Princeton.EDU (G. Philippe Menos) (06/22/91)
Can someone tell me if the Ingres environment incorporates some mechanism(s) for transaction management and crash protection? If so, please describe... Or, alternatively, do you tend to code these mechanisms within the applications? With appreciation, Phil Menos Systems Administrator Princeton University Libraries
mcintoshc@ctl.co.nz (06/24/91)
In article <11060@idunno.Princeton.EDU>, gpmenos@phoenix.Princeton.EDU (G. Philippe Menos) writes: > Can someone tell me if the Ingres environment incorporates some > mechanism(s) for transaction management and crash protection? If so, > please describe... Or, alternatively, do you tend to code these mechanisms > within the applications? > Ingres has a transaction log file which logs each transaction. Journal files are created for those tables with journalling enabled. This is automatic apart from the initial 'enable'. From within the code you can specify the handling of transactions and errors at a number of levels. Eg specify autocommit ON will commit after every transaction (select, insert, update delete) - great for simpple updates and queries, lousy for complex, multi-table updates; so set autocommit OFF and you determine the size of these MST's (multi-statement transactions) - the MST is completed on COMMIT or ROLLBACK. You can also specify rollback points to partially roll-out of error situations. The post error recovery obviously depends on the situation, but you can roll- forward from the relevant checkpoint up-to (or from) any specified time. Hope this helps Colin ----------------------------------------------------------------------------- From : Colin McIntosh, Project Manager # .=====. ======== Computertime Ltd, P.O. Box 6243 # / / / / Wellington, New Zealand # / / / Phone: (04) 852 195 # / / / Fax : (04) 828 288 # / / / / Internet: mcintoshc@nzfc.co.nz # ====== / ====== ----------------------------------------------------------------------------- 'God saw what he had created and it was good' Genesis Chapter 1 - just look what man has gone and done to it -----------------------------------------------------------------------------