[comp.databases] Ingres/STAR problem

bg0l+@andrew.cmu.edu (Bruce E. Golightly) (05/16/89)

We're trying to get a STAR data base going on a 6000 series VAX, and having
real problems.

Lock management is driving us crazy. STAR doen't allow the use of SET commands
to modify lock modes or locking, and something is clearly not working right.
We are ending up with a one user version of the data base. Everything is
locking, with the result that we have users crashing out constantly. We
have even lost forms and frame definitions because of locking problems.
Has anyone else seen anything like this?

We are not sure exactly where the problem is coming from. The VAX 6330 is
running under VMS 5.1, which apparently has some problems too, so we're not
sure if we're looking at an Ingres or VMS problem.

Problem number 2 - system catalogs within STAR. SYSMOD doesn't touch the
STAR specific catalogs. We can get it to modify the system catalogs that
are "normal" with in the STAR data base area, but cannot get the others
modified. Any suggestions?

robf@squid.rtech.com (Robert Fair) (05/17/89)

[Problem running Star on VMS 5.1]

INGRES has only just been certified to run on VMS 5, including 5.1 - make 
sure you have the most up-to-date version of INGRES.  

[Problem SYSMODing STAR-specific system catalogs]

This is a funny in 5.0 - the Star catalogs are created in the coordinator
database already modified, and shouldn't need changing unless you have
a lot of  activity in adding/deleting machine nodes or links. If you
do need to re-modify the STAR catalogs (iinode, iilink etc) go into
the coordinator database as a user with privilege to access the system
catalogs (the INGRES user is a good idea, or the DBA with the -u flag),
specify the +U flag to allow system catalogs to be updated, check the
table structures with the HELP command, and then simply re-MODIFY them.

Notes: 
1) This procedure is NOT generally recommended or supported, since
   updating the system catalogs can be dangerous if you make a typo.

2) Changing the structure/keys for any system catalogs from the default
   values is strongly NOT recommended, and may have unpleasant results.

In INGRES 6.2 the SYSMOD command seems to handle STAR databases directly, 
and optimizes all the STAR catalogs very nicely!  (At least it did when
I tested it...)

Robert Fair
RTI Tech Support

bg0l+@andrew.cmu.edu (Bruce E. Golightly) (05/18/89)

We tried a couple of things that seem to have helped a little. Frankly,
what we've done is cheating and may be risky.

I got into the STAR data base as if it were a regular data base. This can be
done by tacking II onto the front of the data base name. I then manually
modified the STAR specific catalogs to their normal structures. This is the
sort of action normally taken by SYSMOD.

This has resolved some of our problems for the time being. We can, at this
point, have several developers working at the same time with FEWER locking
problems. A test allowed us to have 4 out of 5 developers successfully
working on VIFRED forms concurrently.

We're extremely worried about the underlying problem, though. We plan to
perform some additional experiments to see if there are other things we
can do to eliminate or further reduce the locking problems. Our concern
is for the future.

What happens when we're got N users trying to retrieve/update data table
in this STAR data base? Tolerating locking problems during the development
phase is quite different than trying to live with them in production. Some
the the planned tables for this application are going to be quite large,
and will see heavy concurrent usage in both retrieve and update modes.
I'll pass along further developments as they occur.

Bruce