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From "Paul Rogers (JIRA)" <j...@apache.org>
Subject [jira] [Issue Comment Deleted] (DRILL-4704) select statement behavior is inconsistent for decimal values in parquet
Date Fri, 05 Aug 2016 00:30:20 GMT

     [ https://issues.apache.org/jira/browse/DRILL-4704?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel
]

Paul Rogers updated DRILL-4704:
-------------------------------
    Comment: was deleted

(was: The proximate cause of this particular issue is the mechanism by which the cast function
is being generated. As others have noted, the code is passing through lines 316-316. My guess
is that the materializer is working out how to call this function:

    Decimal28SparseFunctions.Decimal28SparseEqual( Decimal28Sparse left, Decimal28Sparse right
)

The materializer sees: D28SEqual( Decimal28Sparse, Integer ) 

The code wants to convert the Integer to a Decimal28Sparse. It asks the argument for its precision
and scale. But, since the argument just specifies the "minor type" (SQL type), it does not
have the extended attributes of precision and scale. Thus, the annotations in the function
definition are the ultimate cause of the precision being 0:

        @Param Decimal28SparseHolder left;
        @Param Decimal28SparseHolder right;

Now, we might argue that the code should be using, as the target (p, s) the (p,s) of the left
argument (the one that is already a decimal). But, the materializer does not know that this
is an operator; it treats all functions the same (operators and otherwise.) So, the materializer
does not know that we should treat arguments in this way. All it knows is that it has an Integer
and wants a D28S (of, presumably, any p & s).

Next, we can ask how DS28Equal handles the (p,s) of the two arguments: must they be the same
or can they be different? Looking at the code (as best as I can tell), the code will align
values with different (p,s) values. Thus, say, values of Decimal28( 10, 2 ) and Decimal28(
8, 0 ) will compare properly.

So, back to the cast from Integer to D28S. As Dave suggests, we can interpret (precision ==
0) to mean "you figure it out": we can set (p,s) way we want.

Dave's fix computes the precision based on the actual integer value. But, since the comparison
can handle any valid (p,s), we might as well set them to a constant. Since the maximum Integer
value is 2 billion, we can just use a constant (10,0).

If the selected precision is constant, then the cost is low and the solution is fine for both
for constant integers (as in the original case), and for per-row conversions (as in Aman's
concern.))

> select statement behavior is inconsistent for decimal values in parquet
> -----------------------------------------------------------------------
>
>                 Key: DRILL-4704
>                 URL: https://issues.apache.org/jira/browse/DRILL-4704
>             Project: Apache Drill
>          Issue Type: Bug
>          Components: Functions - Drill
>    Affects Versions: 1.6.0
>         Environment: Windows 7 Pro, Java 1.8.0_91
>            Reporter: Dave Oshinsky
>             Fix For: Future
>
>
> A select statement that searches a parquet file for a decimal value matching a specific
value behaves inconsistently.  The query expressed most simply finds nothing:
> 0: jdbc:drill:zk=local> select * from dfs.`c:/archiveHR/HR.EMPLOYEES` where employee_id
= 100;
> +--------------+-------------+------------+--------+---------------+-----------+
> | EMPLOYEE_ID  | FIRST_NAME  | LAST_NAME  | EMAIL  | PHONE_NUMBER  | HIRE_DATE |
> +--------------+-------------+------------+--------+---------------+-----------+
> +--------------+-------------+------------+--------+---------------+-----------+
> No rows selected (0.348 seconds)
> The query can be modified to find the matching row in a few ways, such as the following
(using between instead of '=', changing 100 to 100.0, or casting as decimal:
> 0: jdbc:drill:zk=local> select * from dfs.`c:/archiveHR/HR.EMPLOYEES` where employee_id
between 100 and 100;
> +--------------+-------------+------------+--------+---------------+-----------+
> | EMPLOYEE_ID  | FIRST_NAME  | LAST_NAME  | EMAIL  | PHONE_NUMBER  |       HIR |
> +--------------+-------------+------------+--------+---------------+-----------+
> | 100          | Steven      | King       | SKING  | 515.123.4567  | 2003-06-1 |
> +--------------+-------------+------------+--------+---------------+-----------+
> 1 row selected (0.226 seconds)
> 0: jdbc:drill:zk=local> select * from dfs.`c:/archiveHR/HR.EMPLOYEES` where employee_id
= 100.0;
> +--------------+-------------+------------+--------+---------------+-----------+
> | EMPLOYEE_ID  | FIRST_NAME  | LAST_NAME  | EMAIL  | PHONE_NUMBER  |       HIR |
> +--------------+-------------+------------+--------+---------------+-----------+
> | 100          | Steven      | King       | SKING  | 515.123.4567  | 2003-06-1 |
> +--------------+-------------+------------+--------+---------------+-----------+
> 1 row selected (0.259 seconds)
> 0: jdbc:drill:zk=local> select * from dfs.`c:/archiveHR/HR.EMPLOYEES` where cast(employee_id
AS DECIMAL) = 100;
> +--------------+-------------+------------+--------+---------------+-----------+
> | EMPLOYEE_ID  | FIRST_NAME  | LAST_NAME  | EMAIL  | PHONE_NUMBER  |       HIR |
> +--------------+-------------+------------+--------+---------------+-----------+
> | 100          | Steven      | King       | SKING  | 515.123.4567  | 2003-06-1 |
> +--------------+-------------+------------+--------+---------------+-----------+
> 1 row selected (0.232 seconds)
> 0: jdbc:drill:zk=local>
> The schema of the parquet data that is being searched is as follows:
> $ java -jar parquet-tools*1.jar meta c:/archiveHR/HR.EMPLOYEES/1.parquet
> file:           file:/c:/archiveHR/HR.EMPLOYEES/1.parquet
> creator:        parquet-mr version 1.8.1 (build 4aba4dae7bb0d4edbcf7923ae1339f28fd3f7fcf)
> .....
> file schema:    HR.EMPLOYEES
> --------------------------------------------------------------------------------
> EMPLOYEE_ID:    REQUIRED FIXED_LEN_BYTE_ARRAY O:DECIMAL R:0 D:0
> FIRST_NAME:     OPTIONAL BINARY O:UTF8 R:0 D:1
> LAST_NAME:      REQUIRED BINARY O:UTF8 R:0 D:0
> EMAIL:          REQUIRED BINARY O:UTF8 R:0 D:0
> PHONE_NUMBER:   OPTIONAL BINARY O:UTF8 R:0 D:1
> HIRE_DATE:      REQUIRED BINARY O:UTF8 R:0 D:0
> JOB_ID:         REQUIRED BINARY O:UTF8 R:0 D:0
> SALARY:         OPTIONAL FIXED_LEN_BYTE_ARRAY O:DECIMAL R:0 D:1
> COMMISSION_PCT: OPTIONAL FIXED_LEN_BYTE_ARRAY O:DECIMAL R:0 D:1
> MANAGER_ID:     OPTIONAL FIXED_LEN_BYTE_ARRAY O:DECIMAL R:0 D:1
> DEPARTMENT_ID:  OPTIONAL FIXED_LEN_BYTE_ARRAY O:DECIMAL R:0 D:1
> row group 1:    RC:107 TS:9943 OFFSET:4
> --------------------------------------------------------------------------------
> EMPLOYEE_ID:     FIXED_LEN_BYTE_ARRAY SNAPPY DO:0 FPO:4 SZ:360/355/0.99 VC:107 ENC:PLAIN,BIT_PACKED
> FIRST_NAME:      BINARY SNAPPY DO:0 FPO:364 SZ:902/1058/1.17 VC:107 ENC:PLAIN_DICTIONARY,RLE,BIT_PACKED
> LAST_NAME:       BINARY SNAPPY DO:0 FPO:1266 SZ:913/1111/1.22 VC:107 ENC:PLAIN,BIT_PACKED
> EMAIL:           BINARY SNAPPY DO:0 FPO:2179 SZ:977/1184/1.21 VC:107 ENC:PLAIN,BIT_PACKED
> PHONE_NUMBER:    BINARY SNAPPY DO:0 FPO:3156 SZ:750/1987/2.65 VC:107 ENC:PLAIN,RLE,BIT_PACKED
> HIRE_DATE:       BINARY SNAPPY DO:0 FPO:3906 SZ:874/2636/3.02 VC:107 ENC:PLAIN_DICTIONARY,BIT_PACKED
> JOB_ID:          BINARY SNAPPY DO:0 FPO:4780 SZ:254/302/1.19 VC:107 ENC:PLAIN_DICTIONARY,BIT_PACKED
> SALARY:          FIXED_LEN_BYTE_ARRAY SNAPPY DO:0 FPO:5034 SZ:419/580/1.38 VC:107 ENC:PLAIN,RLE,BIT_PACKED
> COMMISSION_PCT:  FIXED_LEN_BYTE_ARRAY SNAPPY DO:0 FPO:5453 SZ:97/113/1.16 VC:107 ENC:PLAIN,RLE,BIT_PACKED
> MANAGER_ID:      FIXED_LEN_BYTE_ARRAY SNAPPY DO:0 FPO:5550 SZ:168/363/2.16 VC:107 ENC:PLAIN,RLE,BIT_PACKED
> DEPARTMENT_ID:   FIXED_LEN_BYTE_ARRAY SNAPPY DO:0 FPO:5718 SZ:94/254/2.70 VC:107 ENC:PLAIN,RLE,BIT_PACKED



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