Conference orarep::nomahs::rdb_60

5116.0. "Database Snapshot Mode" by M5::BLEHLBAC (RDB: 34% better than real life) Thu Mar 06 1997 14:30

Hi,

  I coulda sworn that I've seen a discussion about this before but I'm
unable to find anything.

  The "snapshot mode" information in the "Database Parameters" portion
of the db header may not accurately reflect the actual snapshot mode.
I have a customer that altered his db to "snaps are disabled" but the
snap mode in the db parameters showed "snaps are deferred".  I told
him that he needs to look at the individual storage area info to look
at the snap mode, and, they all said "disabled".

  Liz Wilcox enlightened me as to the cause of this behavior - in
dbms, areas can have different snap modes and the snap mode in the
db parameters indicated what the snap mode will be if snaps are enabled
for an area.  Such is not the case in Rdb.

  Questions:

  1) can/will this dbms functionality be added to Rdb??

  2) if not, should the db parameter snap mode accurately reflect the
     actual snap mode setting??

                            Thanks,  Barry

~  1) can/will this dbms functionality be added to Rdb??

Maybe.  We added EXTENT DISABLED in V6.0 and we added ALG COUNT for Rdb7.  SO
as things come to be useful we enable them.  Each one adds some level of
complexity so we resist adding everything at once...

~  2) if not, should the db parameter snap mode accurately reflect the
~     actual snap mode setting??

It is reflecting what it knows.

Ian

re: .1

  OK ..... thanks, sounds reasonable to me.

Well, the "mode" refers to snaps being either deferred or non-deferred, which
is different from whether or not they are enabled or disabled.  Mode says
"this is HOW they will be enabled IF they are enabled".

Liz