Sumit Nigam created PHOENIX-2514:
------------------------------------
Summary: Even with ORDER BY clause the LIMIT does not work
correctly with salted tables containing many records.
Key: PHOENIX-2514
URL: https://issues.apache.org/jira/browse/PHOENIX-2514
Project: Phoenix
Issue Type: Bug
Affects Versions: 4.5.1
Environment: HBase-0.98.14
Reporter: Sumit Nigam
Priority: Critical
Fix For: 4.5.1
A query such as SELECT CURRENT_TIMESTAMP FROM TBL ORDER BY CURRENT_TIMESTAMP
DESC LIMIT 1 does not really return the MAX(CURRENT_TIMESTAMP). The table is
salted and has 200272 records.
select current_timestamp from TBL order by current_timestamp desc limit 1;
+------------------------------------------+
| CURRENT_TIMESTAMP |
+------------------------------------------+
| 1448815328556 |
+------------------------------------------+
select max(current_timestamp) from TBL;
+------------------------------------------+
| MAX("CURRENT_TIMESTAMP") |
+------------------------------------------+
| 1449732792090 |
+------------------------------------------+
The results are different. MAX is of course, returning the right record.
The above query is one example. There are other queries which also seem to be
returning incorrect record with ORDER BY and LIMIT.
Is this also correct that when there is a WHERE clause limiting the number of
projected records, then LIMIT seems to work fine? I seem to be noticing that
also.
The table DDL is:
CREATE TABLE IF NOT EXISTS TBL
(CURRENT_TIMESTAMP BIGINT NOT NULL, ID VARCHAR(96), CURR_EXDOC VARCHAR,
CURR_CHECKSUM VARCHAR(32), SUMMARY VARCHAR,
CONSTRAINT PK PRIMARY KEY(CURRENT_TIMESTAMP, ID))
BLOCKCACHE=FALSE, COMPRESSION=SNAPPY, SALT_BUCKETS=8
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