Thanks for your reply Josh Elser. scan.setMaxResultSize() is set to 10 MB I tried setting Scan.setBatch() with different values, I could see that there is improvement compared to earlier, but I did not see any variation in the performance for different fetch sizes. After setting scan.setMaxResultSize() is to 10 MB+ the new perf numbers are as below . Fetch Size (Number of Rows) . 1000 2000 5000 7500 10000 15000 20000 Java API time 17692 17158 21524 21289 18802 18786 18786 For any batch size, performance is almost consistent. Where as with REST I could see the improvement on higher fetch size. Till batch Size 10000 - Java Client looks good. Above 10000 batch size REST looks better .. why ? What other parameters might be impacting this . ... View more