Delay in connection to a database

>>> chapman  13/August/1996 01:55pm >>>
I'm seeing the following symptom.... occasional delay of 5-10 seconds
at the point where one connects to a db, either when running a utility
like 'tables' or 'isql' or an esql program.  Then (run the program
immediately a second time, and see a very fast connect).... feels like 
something's swapped out that needs to be swapped back in, and the system 
is taking its sweet time.   


A thing to note is that when INGRES first connects
to a database it loads the system catalogs into
cache.  Thus the first connect to the database
will take a little time, but each connect after
that will not need to go through the database
setup routine and will connect almost instantly.

The system catalogues will stay in memory so long
as someone has a session open against the
database.  If at sometime all connections to a
database are closed
it is possible for the database connect details
and system catalogues be
released.  Thus the next call to the database
would agaib need to go through the database
connect routine and load the catalogues into
memory.

It's an old sales trick to have an 'sql' session
going somewhere with a connection to the database
they are going to demonstrate against.  Thus when
they start the demonstration the database appears
instantly dazzling the crowd.

The details might not be exact but the idea is
there.

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Steve Clements                         If you can
find an opinion here its
About Time Software Solutions          yours to
keep.
Brisbane, Queensland, Australia
President of Vice, Queensland IUA      Email:
clemens@pcux.citec.qld.gov.au
ph & fax: 61-7-3217-2118                 or  
sclement@interconnect.com.au
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