Re: Phantom Inserts

Posted in 1995

Jay Feenan — 8 MAR 95 20:21:46 EDT — source: Informix-list mailing list archive (1991-1998)

In article <3jg60n$lmr@gatekeeper.cognos.com>, nigelc@Cognos.COM (Nigel Campbell) writes... . . . >Interbase provides phantom protection by default without requiring >readers to block writers or vice versa. Rather than use locking >on tables or indexes etc InterBase uses row versioning. Your >transaction can only see those rows whose transaction id is known >to be committed. >-- >Nigel Campbell Voice: (613) 738-1338 ext 3016 P.O. Box 9707 >Desktop Division FAX: (613) 738-0002 3755 Riverside Dr. >Cognos Incorporated MCI: nigel campbell || 3074729 Ottawa, Ontario >UUnet: nigelc@cognos.COM CANADA K1G 3Z4 My first post failed... Interbase has some 'roots' with DEC Rdb/ELN product so I'm assuming the following is true: USER1 USER2 start tran select all foo where bar = 1 start trans Insert foo (bar 1) commit select all foo where bar = 1 would produce an error on the second select by user 1 if it did phantom prevention [I guess I would call this detection]...and not using a blocking scheme. No?!?!? -Jay Feenan ********************************************************************* *** Jay Feenan *** *** Oracle Rdb Engineering *** *** *** *** opinions expressed here are solely my own and not those of my *** *** employer. *** *** *** *********************************************************************