Divide by zero in logging code

[Jim <ji...@gmail.com>]

I sent this to the pre-apache status github issues list. I guess that 
github account is inactive now.

I'm getting a divide by zero in the timing measurement code of 
InternalParquetRecordReader at line 109 here: 
https://github.com/apache/incubator-parquet-mr/blob/master/parquet-hadoop/src/main/java/parquet/hadoop/InternalParquetRecordReader.java#L109

totalTime is 0 and there's no check.

In gerneral I find this code somewhat confusing in that it's not obvious 
what's being tracked (it operates through the side effect of updating 
certain timing values and assuming it will be called at certain points 
of the reading lifecycle). With each call to "checkRead" the 
startedAssemblingCurrentBlockAt is reset to the current time. If 
checkRead is called again within a millisecond then this is likely to fail.

Also, why are all these timing measurements taken 
(System.currentTimeMillis is called twice in this one method) and 
strings constructed for logging when the logging might not even be at 
INFO level (it seems this code has no operational purpose unless logging 
is at INFO)?