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Greater than more efficient than equals?

AleKaOct 20 2015 — edited Oct 28 2015

Good morning,

in our company we manage multiple client databases oracle .

Our framework "versions" records using  2  NUMBER(18) fields (lets call NSTART and NEND). So that we have, for example:

ExtId   |    NSTART  |             NEND          |....and so on

+++++++++++++++++++++++++++++++++

  1       |     1            |    10                          |.....

  1       |     10          |    12                          |....and so on

  1       |      12         | 999999999999999999 |....and so on

  2       |     67          |    789                        |....and so on

  2       |     789        | 999999999999999999 |....and so on


The record with 999999999999999999 is the "last version record".

It happens that we have to identify the last version, so we look for the NEND = 999999999999999999.

In databases  with million records, the "research" is really long and often seems to freeze...but we discovered that if we just change:

NEND = 999999999999999999

with

NEND > 999999999999999998


it is much more faster (doesnt freeze and takes just seconds, not minutes....)


Why?


Thanks

Alex

Comments

Billy Verreynne

A session is the logical entity that services a specific db client connection.
A process is the physical entity that executes a session.
With dedicated server, each session has its own physical process for execution. 1:1 relationship. A 100 sessions mean a 100 processes.
With shared server, sessions share a pool of processes, where any idle process can be tasked to execute any shared server session. A 100 processes in the pool can service a 1000 shared sessions. However, if all 100 processes are busy, then 900 sessions need to wait for an idle process in order to to be serviced.

sol-danesh

And What is the method of setting these two parameters in Oracle architectures?

sol-danesh

Thank you dear Billy Verreynne.
As a result, it can be said that dedicated architecture is better for projects with a large number of users?

Billy Verreynne

Basic parameters for shared server are DISPATCHERS and SHARED_SERVERS.
Shared Server is ideal for supporting a large number of OLTP type users, servicing 1000s of user requests that are of short duration to service. Note that UGA memory is stored in the SGA.
Dedicated Server is ideal for supporting OLAP type users, servicing 100s of user requests that are of long duration to service. Note that UGA memory is stored in the PGA.
The Oracle database can use both architectures at the same time.

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Locked on Nov 25 2015
Added on Oct 20 2015
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