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From "Alex Chistyakov (JIRA)" <j...@apache.org>
Subject [jira] [Created] (PHOENIX-4359) Explain plan returns incorrect number of EST_BYTES_READ and EST_ROWS_READ for a salted table
Date Wed, 08 Nov 2017 18:06:00 GMT
Alex Chistyakov created PHOENIX-4359:
----------------------------------------

             Summary: Explain plan returns incorrect number of EST_BYTES_READ and EST_ROWS_READ
for a salted table
                 Key: PHOENIX-4359
                 URL: https://issues.apache.org/jira/browse/PHOENIX-4359
             Project: Phoenix
          Issue Type: Bug
    Affects Versions: 4.11.0
            Reporter: Alex Chistyakov


Table INVOICES_V6 is a salted version of INVOICES_V5 with exactly the same data.
Two exact queries have very different plans on them:
{{0: jdbc:phoenix:192.168.160.123,192.168.160.1> EXPLAIN SELECT COUNT(*) FROM INVOICES_V5
WHERE ( ( PERIOD = 'y2016q2' AND OWNER_INN = '6685003522' ) );
+----------------------------------------------------------------------------------------------------+-----------------+----------------+
|                                                PLAN                                    
           | EST_BYTES_READ  | EST_ROWS_READ  |
+----------------------------------------------------------------------------------------------------+-----------------+----------------+
| CLIENT 1-CHUNK 0 ROWS 0 BYTES PARALLEL 1-WAY RANGE SCAN OVER INVOICES_V5 ['y2016q2','6685003522']
 | 0               | 0              |
|     SERVER FILTER BY FIRST KEY ONLY                                                    
           | 0               | 0              |
|     SERVER AGGREGATE INTO SINGLE ROW                                                   
           | 0               | 0              |
+----------------------------------------------------------------------------------------------------+-----------------+----------------+
3 rows selected (0.046 seconds)
0: jdbc:phoenix:192.168.160.123,192.168.160.1> SELECT /*+ SKIP_SCAN, NO_CACHE */ COUNT(*)
FROM INVOICES_V6 WHERE ( ( PERIOD = 'y2016q2' AND OWNER_INN = '6685003522' ) );
+-----------+
| COUNT(1)  |
+-----------+
| 108       |
+-----------+
1 row selected (0.185 seconds)
0: jdbc:phoenix:192.168.160.123,192.168.160.1> EXPLAIN SELECT COUNT(*) FROM INVOICES_V6
WHERE ( ( PERIOD = 'y2016q2' AND OWNER_INN = '6685003522' ) );
+----------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+----------------+
|                                                                           PLAN         
                                                                 | EST_BYTES_READ  | EST_ROWS_READ
 |
+----------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+----------------+
| CLIENT 256-CHUNK 58635313 ROWS 67874370912 BYTES PARALLEL 256-WAY RANGE SCAN OVER INVOICES_V6
[0,'y2016q2','6685003522'] - [255,'y2016q2','6685003522']  | 67874370912     | 58635313  
    |
|     SERVER FILTER BY FIRST KEY ONLY                                                    
                                                                 | 67874370912     | 58635313
      |
|     SERVER AGGREGATE INTO SINGLE ROW                                                   
                                                                 | 67874370912     | 58635313
      |
+----------------------------------------------------------------------------------------------------------------------------------------------------------+-----------------+----------------+
3 rows selected (0.048 seconds)
0: jdbc:phoenix:192.168.160.123,192.168.160.1>}}
The plan on V6 doesn't seem to be real, Phoenix definitely does not read 60+ Gb.



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