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Posted to dev@abdera.apache.org by "Rafit Izhak Ratzin (JIRA)" <ji...@apache.org> on 2015/08/24 18:10:47 UTC
[jira] [Created] (ABDERA-426) Group by a divided value (e.g.,
time/10) returns NULL.
Rafit Izhak Ratzin created ABDERA-426:
-----------------------------------------
Summary: Group by a divided value (e.g., time/10) returns NULL.
Key: ABDERA-426
URL: https://issues.apache.org/jira/browse/ABDERA-426
Project: Abdera
Issue Type: Bug
Reporter: Rafit Izhak Ratzin
Running with an environment that includes: phoenix version 4.5.0, HBase version 0.98, Cloudera 5.2
When I group by a divided value (e.g., time/10) the divided value will return as NULL.
Please see the simple examples below,
Thanks in advance,
--Rafit
create table test(time integer not null, hostname varchar not null,usage float constraint pk PRIMARY KEY(time, hostname));
upsert into test values(1439853441,'qa8',3.28);
upsert into test values(1439853449,'qa8',3.28);
upsert into test values(1439853459,'qa8',3.28);
upsert into test values(1439853458,'qa8',3.27);
upsert into test values(1439853457,'qa8',6.27);
upsert into test values(1439853462,'qa8',8.27);
upsert into test values(1439853462,'qa9',8.27);
upsert into test values(1439853457,'qa9',6.27);
0: jdbc:phoenix:localhost> select * from test;
+------------------------------------------+------------------------------------------+----------------------------------------+
| TIME | HOSTNAME | USAGE |
+------------------------------------------+------------------------------------------+----------------------------------------+
| 1439853441 | qa8 | 3.28 |
| 1439853449 | qa8 | 3.28 |
| 1439853457 | qa8 | 6.27 |
| 1439853457 | qa9 | 6.27 |
| 1439853458 | qa8 | 3.27 |
| 1439853459 | qa8 | 3.28 |
| 1439853462 | qa8 | 8.27 |
| 1439853462 | qa9 | 8.27 |
+------------------------------------------+------------------------------------------+----------------------------------------+
0: jdbc:phoenix:localhost> select time/10, hostname, usage from test;
+----------------------------------------+------------------------------------------+------------------------------------------+
| (TIME / 10) | HOSTNAME | USAGE |
+----------------------------------------+------------------------------------------+------------------------------------------+
| 143985344 | qa8 | 3.28 |
| 143985344 | qa8 | 3.28 |
| 143985345 | qa8 | 6.27 |
| 143985345 | qa9 | 6.27 |
| 143985345 | qa8 | 3.27 |
| 143985345 | qa8 | 3.28 |
| 143985346 | qa8 | 8.27 |
| 143985346 | qa9 | 8.27 |
+----------------------------------------+------------------------------------------+------------------------------------------+
0: jdbc:phoenix:localhost> select time/10 as tm, hostname, avg(usage) from test group by hostname, tm;
+----------------------------------------+------------------------------------------+------------------------------------------+
| TM | HOSTNAME | AVG(USAGE) |
+----------------------------------------+------------------------------------------+------------------------------------------+
| null | | 3.2799 |
| null | | 4.2733 |
| null | | 6.2699 |
| null | | 8.27 |
| null | | 8.27 |
+----------------------------------------+------------------------------------------+------------------------------------------+
hostname is empty, time/10 is null
I thought it might be related to the fact that the time is a primary key so I ran the next test case:
0: jdbc:phoenix:localhost> create table test1(time integer not null, hostname varchar not null,usage float,period integer constraint pk PRIMARY KEY(time, hostname));
0: jdbc:phoenix:localhost> upsert into test1 values(1439853462,'qa9',8.27,1439853462);
0: jdbc:phoenix:localhost> upsert into test1 values(1439853461,'qa9',8.27,1439853362);
0: jdbc:phoenix:localhost> upsert into test1 values(1439853461,'qa9',5.27,1439853461);
0: jdbc:phoenix:localhost> upsert into test1 values(1439853451,'qa9',4.27,1439853451);
0: jdbc:phoenix:localhost> select * from test1;
+-------------------------------------+-------------------------------------+--------------------------------------+---------------------------------------+
| TIME | HOSTNAME | USAGE | PERIOD |
+-------------------------------------+-------------------------------------+--------------------------------------+---------------------------------------+
| 1439853451 | qa9 | 4.27 | 1439853451 |
| 1439853461 | qa9 | 5.27 | 1439853461 |
| 1439853462 | qa9 | 8.27 | 1439853462 |
+-------------------------------------+------------------------------------+--------------------------------------+----------------------------------------+
0: jdbc:phoenix:localhost> select period/10 as tm, hostname, usage from test1 ;
+----------------------------------------+------------------------------------------+------------------------------------------+
| TM | HOSTNAME | USAGE |
+----------------------------------------+------------------------------------------+------------------------------------------+
| 143985345 | qa9 | 4.27 |
| 143985346 | qa9 | 5.27 |
| 143985346 | qa9 | 8.27 |
+----------------------------------------+------------------------------------------+------------------------------------------+
+----------------------------------------+------------------------------------------+------------------------------------------+
| TM | HOSTNAME | AVG(USAGE) |
+----------------------------------------+------------------------------------------+------------------------------------------+
| null | qa8 | 4.2699 |
| null | qa9 | 4.2699 |
| null | qa9 | 6.77 |
+----------------------------------------+------------------------------------------+------------------------------------------+
Now we can see the hostname (it is not an empty field as before) but tm is still null.
Please see below the response from James for a work arround:
Hi Rafit,
Looks like a bug. Please file a JIRA. The following seems to work as a workaround:
select cast(time/10.0 as integer) as tm, hostname, avg(usage) from test group by hostname, tm;
You might also consider using a date[1] type instead of an integer and then using the TRUNC function[2] which work with both numeric and time types.
Thanks,
James
[1] https://phoenix.apache.org/language/datatypes.html#date_type
[2] https://phoenix.apache.org/language/functions.html#trunc
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