how would esp do when it was launched?

[Liu, Yao-Hua (Joshua)]

Hi all,

       Suresh and I found some interesting thing when run some queries.

       Step 1:
       Use trafci, run query: select count(*) from CELL_INDICATOR_HIVE where 
starttime=20170801000000000;  // CELL_INDICATOR_HIVE has 100 billion rows and 
each starttime would have 4346483 rows. Starttime is the first column in store 
by keys
       This would take about 1 minute and 20 seconds to finish.
       Step2
       Run above sql again, then it would take 3 seconds to finish.
       Here 80s vs 3s, we may guess it's due to esp start time or cache. But we 
checked,

1.     to start all the esps would take less than 1 seconds.

2.     If due to cache, we can run another table for a test:
       Step3
       Run another query: select count(*) from SERVERIP_INDICATOR_BAK where 
starttime=20170801000000000;  // SERVERIP_INDICATOR_BAK has 64 billion rows and 
each starttime would have 2.8 million rows. Starttime is also the first column 
in store by keys. Then it would take 2 seconds to finish.

       By the way, if we start another trafci(not the same mxosrvr from above) 
and run above select count(*) from SERVERIP_INDICATOR_BAK where 
starttime=20170801000000000, it would also take 1 minute or more.

       So we are wondering what does esp do when it was started? Why the first 
time the esp to scan one table would take so much time but the second time to 
scan another table could be much faster?

Thanks
Joshua