How can we know if the governor limit already exceeded or not in salesforce?

Hi saurabh,

You will get to know it by using limit class in Salesforce.

Just refer to thi sexample code :

trigger accountLimitExample on Account (after delete, after insert, after update) {

System.debug('Total Number of SOQL Queries allowed in this Apex code context: ' + Limits.getLimitQueries());
System.debug('Total Number of records that can be queried in this Apex code context: ' + Limits.getLimitDmlRows());
System.debug('Total Number of DML statements allowed in this Apex code context: ' + Limits.getLimitDmlStatements() );
System.debug('Total Number of CPU usage time (in ms) allowed in this Apex code context: ' + Limits.getLimitCpuTime());

// Query the Opportunity object
List<Opportunity> opptys =
[select id, description, name, accountid, closedate, stagename from Opportunity where accountId IN: Trigger.newMap.keySet()];

System.debug('1. Number of Queries used in this Apex code so far: ' + Limits.getQueries());
System.debug('2. Number of rows queried in this Apex code so far: ' + Limits.getDmlRows());
System.debug('3. Number of DML statements used so far: ' + Limits.getDmlStatements());
System.debug('4. Amount of CPU time (in ms) used so far: ' + Limits.getCpuTime());

//NOTE:Proactively determine if there are too many Opportunities to update and avoid governor limits
if (opptys.size() + Limits.getDMLRows() > Limits.getLimitDMLRows()) {
System.debug('Need to stop processing to avoid hitting a governor limit. Too many related Opportunities to update in this trigger');
System.debug('Trying to update ' + opptys.size() + ' opportunities but governor limits will only allow ' + Limits.getLimitDMLRows());
for (Account a : Trigger.new) {
a.addError('You are attempting to update the addresses of too many accounts at once. Please try again with fewer accounts.');
}
}

else{
System.debug('Continue processing. Not going to hit DML governor limits');
System.debug('Going to update ' + opptys.size() + ' opportunities and governor limits will allow ' + Limits.getLimitDMLRows());
for(Account a : Trigger.new){
System.debug('Number of DML statements used so far: ' + Limits.getDmlStatements());

for(Opportunity o: opptys){
if (o.accountid == a.id)
o.description = 'testing';
}

}
update opptys;
System.debug('Final number of DML statements used so far: ' + Limits.getDmlStatements());
System.debug('Final heap size: ' + Limits.getHeapSize());
}
}

Thanks.