Hi Abishek,

What is meant with 'reduce the use of try/catch' is that you should make 
sensible use of try/catch and manually throwing exceptions using the error 
function. Exception handling is (relatively) slow in most languages, so if you 
have the option to prevent a throw and a catch by simply using an extra if, 
then do so. On other occasions, you might want to be sure certain statements 
are always executed, or that certain actions are taken when an exception is 
thrown.

A good example is trying to connect to an external resource using 
xdmp:http-get. If it fails with a timeout, it throws an exception. It is not 
uncommon to put a try catch around it and connect to a different resource, or 
return some default value instead.

Personally, I don't bother about try/catch performance too much. Just use them 
sensibly..

Kind regards,
Geert

Van: [email protected] 
[mailto:[email protected]] Namens Abishek N
Verzonden: donderdag 5 mei 2011 19:05
Aan: General MarkLogic Developer Discussion
Onderwerp: [MarkLogic Dev General] Try catch in xquery

What are the pointers while exception handling in ml?  One of the pointers we 
have already heard is
"Reduce the use of try/catch where applicable. This is especially true in 
situations where try/catch blocks may be nested. Try/catch blocks have a 
negative impact on performance due to the fact that the block must be 
completely evaluated before the server can move on. "

So does this mean that  we have to avoid having try catch blocks around lots of 
lines of code?   and try to keep the try catch block as short as possible..
So in the eg. below statement 3 try catch block would not be triggered until 
the statement 1 and statement 2 get executed, is that correct? Since statement 
2 is outside try catches there is a possibility it could get lazy evaluated.

try {
statement 1
}
catch{
}

statement 2

try {
statement 3
}
catch{
}

Similarly in the below scenario.. if we have nested try catches like below... 
statement 5 would not get executed until statement 1,2,3 get executed.. however 
statement 4 could get executed..
try {
try
{
statement 1
}
catch{
}

statement 2

try {
statement 3
}
catch{
}

}

statement 4

try {
statement 5
}
catch{
}

Please confirm if our understanding is correct.

Regards Abishek
_______________________________________________
General mailing list
[email protected]
http://developer.marklogic.com/mailman/listinfo/general

Reply via email to