From top of my head, you could set the flag to true based on some
globally unique condition.
Like some specific file name with start offset 0 - like part-00000,
offset 0 (the actual file name could be a jobconf param).
Note that the condition should be repeatable - since tasks can get
reexecuted.
Regards,
Mridul
bharath v wrote:
Hi,
I want a particular "section of code" to run only in any "ONE" of the
mappers . So I employed the following procedure.
Main-Class
{
public boolean flag = true;
Map-Class
{
if(flag)
{
flag=false;
/* section of code */
}
}
I am running this code on in pseudo-distributed mode and its working fine .
I doubt whether this runs correctly in distributed mode because , mappers on
other systems have to notified of the changed "flag" .. Any Comments ? If
this is wrong , any suggestions on what method I must follow to achieve this
functionality in D-mode .
Thanks
