Get recently loaded partitions

Maybe by checking the table's EPOCH column?

Example:

dbadmin=> CREATE TABLE parts (c1 INT NOT NULL, c2 INT) PARTITION BY c1;
CREATE TABLE

dbadmin=> INSERT INTO parts SELECT 1, 1;
 OUTPUT
--------
      1
(1 row)

dbadmin=> INSERT INTO parts SELECT 1, 2;
 OUTPUT
--------
      1
(1 row)

dbadmin=> COMMIT;
COMMIT

dbadmin=> INSERT INTO parts SELECT 2, 3;
 OUTPUT
--------
      1
(1 row)

dbadmin=> INSERT INTO parts SELECT 3, 5;
 OUTPUT
--------
      1
(1 row)

dbadmin=> COMMIT;
COMMIT

dbadmin=> SELECT c1 AS partition_key
dbadmin->   FROM parts
dbadmin->  WHERE parts.epoch = (SELECT MAX(epoch)
dbadmin(>                         FROM parts);
 partition_key
---------------
             2
             3
(2 rows)

dbadmin=> UPDATE parts SET c2 = 10 WHERE c1 = 1 AND c2 = 1;
 OUTPUT
--------
      1
(1 row)

dbadmin=> COMMIT;
COMMIT

dbadmin=> SELECT c1 AS partition_key
dbadmin->   FROM parts
dbadmin->  WHERE parts.epoch = (SELECT MAX(epoch)
dbadmin(>                         FROM parts);
 partition_key
---------------
             1
(1 row)

But you asked for activity in the past 3 hours, so you will need to find the latest Epoch 3 hours ago. One option to get that info is to query the DC_REQUESTS_ISSUED table hoping that it has records that are at least 3 hours old

dbadmin=> SELECT DISTINCT c1 AS partition_key
dbadmin->   FROM parts
dbadmin->  WHERE epoch >= (SELECT MIN(query_start_epoch)
dbadmin(>                    FROM dc_requests_issued
dbadmin(>                   WHERE time >= (SYSDATE::TIMESTAMP - INTERVAL '3 HOURS'));
 partition_key
---------------
             1
             2
             3
(3 rows)

But for my example, I will use a smaller interval.

dbadmin=> INSERT INTO parts SELECT 5, 100;
 OUTPUT
--------
      1
(1 row)

dbadmin=> INSERT INTO parts SELECT 6, 1000;
 OUTPUT
--------
      1
(1 row)

dbadmin=> COMMIT;
COMMIT

dbadmin=> SELECT DISTINCT c1 AS partition_key
dbadmin->   FROM parts
dbadmin->  WHERE epoch >= (SELECT MIN(query_start_epoch)
dbadmin(>                    FROM dc_requests_issued
dbadmin(>                   WHERE time >= (SYSDATE::TIMESTAMP - INTERVAL '1 MINUTE'));
 partition_key
---------------
             5
             6
(2 rows)

@Vertica_Curtis - Fyi, I sent an email to Vanilla support on the posting SQL issue!

@Vertica_Curtis - The issue that caused your SQL post to fail has been resolved. Can you please post the query you mentioned for the benefit of the Community?