SQL Not in vs Join example

Obviously SQL join is more efficient than the not in clause. Here is an example of both.


Most inefficient Not in query :

select count(*)
from
wire_instr w
where
w.short_code
not in (select short_code
from nostro_accts)


Slightly better Not Exists query :

select count(*) from
wire_instr w
where not exists(
select 1
from nostro_accts n where
n.short_code=w.short_code)


Finally the Join query :

Join infact creates a new table which

select w.short_code as wshort,n.short_code as nshort from wire_instr w
left outer join
nostro_accts n
on n.short_code=w.short_code
where n.short_code=null

Enjoy
-Sunny

Replace with new line in eclipse

To replace comma with new line in edit plus.

clrl h in eclipse, enter the character you want to replace, in this case ,
for the new line, click on the downward arrow next to the text and then select new line. See the picture below.



Cheers,
Sonu

Eclipse VM Args

Multiple VM args can be entered to eclipse by separating them with a space. See the picture below :




2) Issue : Eclipse doesnot allow spaces in vm arguments.

You can force eclipse to take a space by wrapping the value of your argument in double quotes.

-Dpropsfile="H:/user data/eclipse/workspace/wires/etc/dev.config.props"

Cheers,
Sonu

Perl in eclipse

Perl Eclipse Tutorials

PDF download of the tutorial above :

Perl ternary operator

I was trying to use an if else stmt in perl inside a join. And it was throwing compilation errors. In this case you can use a ternary operator to serve as if else :

ex :

($Bond{$_}{CFAC} ==-1 ?”N/A” : $Bond{$_}{CFAC})

sybase convert float to char

Sybase function to convert float to char
convert(char(10),isnull(convert(char(18), pi.factor),'N/A')) as factor

Clustering

Horizontal Clustering

Horizontal clustering. A horizontally clustered environment contains multiple physical machines (nodes); see Horizontally clustered environments for more information.

A horizontally clustered environment contains multiple physical machines (nodes), as illustrated in the previous section (Architectural overview of a clustered environment) The cluster-enabled application is deployed to each node and is available for requests. An IP-Sprayer (load balancer (IP Sprayer) provides workload management by distributing requests to the various nodes. A horizontal cluster environment is used for high availability of the management server. In a cluster environment where there is only one active management server, the number of supported management agents should not exceed the number of supported management agents in a single server environment because the management server cannot handle the load.

Advantages :
Provides hardware failover.
Provides all the advantages of a vertical cluster .
Scales.
Can be used in conjunction with vertical clusters.

Disadvantages :
Additional machines require more installation and maintenance.


Vertically clustered environments


Vertical Clustering

Vertical clustering.

A vertically clustered environment contains multiple application server instances hosted on the same physical machine (node). The HTTP server plug-in distributes requests to the various web server instances for processing. A vertical cluster is configured so only one server instance is active at a given time.

Advantages :

Provides process failover.
Increases efficiency with multiple Java(TM) Virtual Machines .
Provides load balancing through workload management.

Disadvantages


Offers minimal scalability.
Does not provide hardware-level failover.


The following shows an example of a vertically clustered environment:



Horizontal and Vertical clusters can be worked in combination