I am struggling with the performance of a SQL of the following
structure:
SELECT <cols>
FROM tab1@remote t1, tab2@remote t2
AND t1.col = t2.col
UNION ALL
SELECT <cols>
FROM localtab1 t1, localtab2 t2
AND t1.col = t2.col
UNION ALL
SELECT <cols>
FROM localtab1 t1, tab2@remote t2
AND t1.col = t2.col
If I run the three statements separately they use about 15, 1 and 6
seconds, but the whole thing takes 220 seconds.
The two databases I'm using are located are located in two different
countries, and the connection between them aren't among the fastest.
As I have understood the Oracle executions the queries will be
executed remotely if all tables in a query is located on the remote
database. I have also tried to use the DRIVING_SITE hint on each of
the query blocks, but it doesn't seem to help.
The version of the local database is 7.3.4 and the remote 8.1.7. 1 2405
We had something similar happening when testing our Applications that
run on 7.3.4 on a 8.1.7.4 Oracle database. Some queries that
connected to a remote database went from 5 seconds to about 15
minutes. The explain plan showed many hash joins in the queries. We
had to set the init.ora parameter hash_join_enabl ed = false, and the
queries ran again in about 5 seconds.
Hope this helps,
David This thread has been closed and replies have been disabled. Please start a new discussion. Similar topics |
by: Andreas Lauffer |
last post by:
I changed from Access97 to AccessXP and I have immense performance
problems.
Details:
- Access XP MDB with Jet 4.0 ( no ADP-Project )
- Linked Tables to SQL-Server 2000 over ODBC
I used the SQL Profile to watch the T-SQL-Command which Access ( who
creates the commands?) creates and noticed:
|
by: Bernie |
last post by:
Greetings,
I have 3 servers all running SQL Server 2000 - 8.00.818. Lets call
them parent, child1, and child 2.
On parent, I create a view called item as follows:
CREATE view Item as
select * from child1.dbchild1.dbo.Item union all
select * from child2.DBChild2.dbo.Item
|
by: serge |
last post by:
I have an SP that is big, huge, 700-800 lines.
I am not an expert but I need to figure out every possible way that
I can improve the performance speed of this SP.
In the next couple of weeks I will work on preparing SQL statements
that will create the tables, insert sample record and run the SP.
I would hope people will look at my SP and...
|
by: Jindrich Prchal |
last post by:
Hi there.
We are running DB2 v7.2 for Win NT on Windows 2000 SP3 machine with
poor configuration AMD 1800+, 512MB RAM and usual IDE harddisk. During
tests of migration our batch programmes written in Visual Age
Generator by IBM from OS390 to Win2000 was this machine our test
machine and migrated programmes ran quick enough there. Batch...
|
by: Joerg Ammann |
last post by:
hi,
os: aix 4.3.3
DB2: version 7 FP3
we are using a federated DB setup, datasource and fed-Db are both
V7FP3 (in fact they are on the same server) and are having massiv
performance problems.
i tracked it back to the way the queries are push-downed to the
| |
by: lyn.duong |
last post by:
Hi,
I have a large table (about 50G) which stores data for over 7 years. I
decided to split this table up into a yearly basis and in order to
allow minimum changes to the applications which access this table, I
created a union all view over the 7 yearly tables.
What I have noticed is that queries against the union all view is
considerably...
|
by: HC |
last post by:
Hello, all, I started out thinking my problems were elsewhere but as I
have worked through this I have isolated my problem, currently, as a
difference between MSDE and SQL Express 2005 (I'll just call it
Express for simplicity).
I have, to try to simplify things, put the exact same DB on two
systems, one running MSDE and one running...
|
by: 73k5blazer |
last post by:
Hello again all..
We have a giant application from a giant software vendor that has very
poor SQL.
It's a PLM CAD application, that makes a call to the db for every cad
node in the assembly.
So for an assembly with many parts, from remote locations, the
performance goes out the window.
Locally, it all works fine because network latency is...
|
by: Terje J?sang |
last post by:
I am struggling with the performance of a SQL of the following
structure:
SELECT <cols>
FROM tab1@remote t1, tab2@remote t2
AND t1.col = t2.col
UNION ALL
SELECT <cols>
FROM localtab1 t1, localtab2 t2
AND t1.col = t2.col
|
by: Hystou |
last post by:
Most computers default to English, but sometimes we require a different language, especially when relocating. Forgot to request a specific language before your computer shipped? No problem! You can effortlessly switch the default language on Windows 10 without reinstalling. I'll walk you through it.
First, let's disable language...
|
by: jinu1996 |
last post by:
In today's digital age, having a compelling online presence is paramount for businesses aiming to thrive in a competitive landscape. At the heart of this digital strategy lies an intricately woven tapestry of website design and digital marketing. It's not merely about having a website; it's about crafting an immersive digital experience that...
| |
by: Hystou |
last post by:
Overview:
Windows 11 and 10 have less user interface control over operating system update behaviour than previous versions of Windows. In Windows 11 and 10, there is no way to turn off the Windows Update option using the Control Panel or Settings app; it automatically checks for updates and installs any it finds, whether you like it or not. For...
|
by: tracyyun |
last post by:
Dear forum friends,
With the development of smart home technology, a variety of wireless communication protocols have appeared on the market, such as Zigbee, Z-Wave, Wi-Fi, Bluetooth, etc. Each protocol has its own unique characteristics and advantages, but as a user who is planning to build a smart home system, I am a bit confused by the...
|
by: agi2029 |
last post by:
Let's talk about the concept of autonomous AI software engineers and no-code agents. These AIs are designed to manage the entire lifecycle of a software development project—planning, coding, testing, and deployment—without human intervention. Imagine an AI that can take a project description, break it down, write the code, debug it, and then...
|
by: TSSRALBI |
last post by:
Hello
I'm a network technician in training and I need your help.
I am currently learning how to create and manage the different types of VPNs and I have a question about LAN-to-LAN VPNs.
The last exercise I practiced was to create a LAN-to-LAN VPN between two Pfsense firewalls, by using IPSEC protocols.
I succeeded, with both firewalls in...
|
by: adsilva |
last post by:
A Windows Forms form does not have the event Unload, like VB6. What one acts like?
|
by: muto222 |
last post by:
How can i add a mobile payment intergratation into php mysql website.
| |
by: bsmnconsultancy |
last post by:
In today's digital era, a well-designed website is crucial for businesses looking to succeed. Whether you're a small business owner or a large corporation in Toronto, having a strong online presence can significantly impact your brand's success. BSMN Consultancy, a leader in Website Development in Toronto offers valuable insights into creating...
| |