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Posted to issues@drill.apache.org by "Vitalii Diravka (JIRA)" <ji...@apache.org> on 2017/11/20 20:17:00 UTC
[jira] [Commented] (DRILL-5970) DrillParquetReader always builds
the schema with "OPTIONAL" dataMode columns instead of "REQUIRED" ones
[ https://issues.apache.org/jira/browse/DRILL-5970?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=16259778#comment-16259778 ]
Vitalii Diravka commented on DRILL-5970:
----------------------------------------
There is an issue with a REQUIRED fields which are part of complex OPTIONAL structures (MAP, LIST), when that parent complex structure is null.
The design to resolve the above issue: internal structures should be stored in Nullable vectors (even if they have REQUIRED DataMode) for the case of parent OPTIONAL complex structure.
For example:
{code}
optional group complex_field (MAP) {
repeated group map (MAP_KEY_VALUE) {
required binary key (UTF8);
required int64 value;
}
}
{code}
Note: MAP_KEY_VALUE is an old annotation group, described here: https://github.com/apache/parquet-format/blob/master/LogicalTypes.md#backward-compatibility-rules-1
{code}
select complex_field from complex_table;
{code}
{code}
---------------------------------------------------------------------------------------------------------------------------------------------------------
| complex_field<MAP(OPTIONAL)>{map<MAP(REPEATED)>{$offsets$<UINT4(REQUIRED)>,key<VARCHAR(OPTIONAL)>,value<BIGINT(OPTIONAL)>}} |
---------------------------------------------------------------------------------------------------------------------------------------------------------
| {"map":[{"key":"Apple","value":2},{"key":"Facebook","value":2}]} |
| {"map":[]} |
---------------------------------------------------------------------------------------------------------------------------------------------------------
{code}
> DrillParquetReader always builds the schema with "OPTIONAL" dataMode columns instead of "REQUIRED" ones
> -------------------------------------------------------------------------------------------------------
>
> Key: DRILL-5970
> URL: https://issues.apache.org/jira/browse/DRILL-5970
> Project: Apache Drill
> Issue Type: Bug
> Components: Execution - Codegen, Execution - Data Types, Storage - Parquet
> Affects Versions: 1.11.0
> Reporter: Vitalii Diravka
> Assignee: Vitalii Diravka
>
> The root cause of the issue is that adding REQUIRED (not-nullable) data types to the container in the all MapWriters is not implemented.
> It can lead to get invalid schema.
> {code}
> 0: jdbc:drill:zk=local> CREATE TABLE dfs.tmp.bof_repro_1 as select * from (select CONVERT_FROM('["hello","hai"]','JSON') AS MYCOL, 'Bucket1' AS Bucket FROM (VALUES(1)));
> SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
> SLF4J: Defaulting to no-operation (NOP) logger implementation
> SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
> +-----------+----------------------------+
> | Fragment | Number of records written |
> +-----------+----------------------------+
> | 0_0 | 1 |
> +-----------+----------------------------+
> 1 row selected (2.376 seconds)
> {code}
> Run from Drill unit test framework (to see "data mode"):
> {code}
> @Test
> public void test() throws Exception {
> setColumnWidths(new int[] {25, 25});
> List<QueryDataBatch> queryDataBatches = testSqlWithResults("select * from dfs.tmp.bof_repro_1");
> printResult(queryDataBatches);
> }
> 1 row(s):
> -------------------------------------------------------
> | MYCOL<VARCHAR(REPEATED)> | Bucket<VARCHAR(OPTIONAL)>|
> -------------------------------------------------------
> | ["hello","hai"] | Bucket1 |
> -------------------------------------------------------
> Total record count: 1
> {code}
> {code}
> vitalii@vitalii-pc:~/parquet-tools/parquet-mr/parquet-tools/target$ java -jar parquet-tools-1.6.0rc3-SNAPSHOT.jar schema /tmp/bof_repro_1/0_0_0.parquet
> message root {
> repeated binary MYCOL (UTF8);
> required binary Bucket (UTF8);
> }
> {code}
> To simulate of obtaining the wrong result you can try the query with aggregation by using a new parquet reader (used by default for complex data types) and old parquet reader. False "Hash aggregate does not support schema changes" error will happen.
> 1) Create two parquet files.
> {code}
> 0: jdbc:drill:schema=dfs> CREATE TABLE dfs.tmp.bof_repro_1 as select * from (select CONVERT_FROM('["hello","hai"]','JSON') AS MYCOL, 'Bucket1' AS Bucket FROM (VALUES(1)));
> +-----------+----------------------------+
> | Fragment | Number of records written |
> +-----------+----------------------------+
> | 0_0 | 1 |
> +-----------+----------------------------+
> 1 row selected (1.122 seconds)
> 0: jdbc:drill:schema=dfs> CREATE TABLE dfs.tmp.bof_repro_2 as select * from (select CONVERT_FROM('[]','JSON') AS MYCOL, 'Bucket1' AS Bucket FROM (VALUES(1)));
> +-----------+----------------------------+
> | Fragment | Number of records written |
> +-----------+----------------------------+
> | 0_0 | 1 |
> +-----------+----------------------------+
> 1 row selected (0.552 seconds)
> 0: jdbc:drill:schema=dfs> select * from dfs.tmp.bof_repro_2;
> {code}
> 2) Copy the parquet files from bof_repro_1 to bof_repro_2.
> {code}
> [root@naravm1 ~]# hadoop fs -ls /tmp/bof_repro_1
> Found 1 items
> -rw-r--r-- 3 mapr mapr 415 2017-07-25 11:46 /tmp/bof_repro_1/0_0_0.parquet
> [root@naravm1 ~]# hadoop fs -ls /tmp/bof_repro_2
> Found 1 items
> -rw-r--r-- 3 mapr mapr 368 2017-07-25 11:46 /tmp/bof_repro_2/0_0_0.parquet
> [root@naravm1 ~]# hadoop fs -cp /tmp/bof_repro_1/0_0_0.parquet /tmp/bof_repro_2/0_0_1.parquet
> [root@naravm1 ~]#
> {code}
> 3) Query the table.
> {code}
> 0: jdbc:drill:schema=dfs> ALTER SESSION SET `planner.enable_streamagg`=false;
> +-------+------------------------------------+
> | ok | summary |
> +-------+------------------------------------+
> | true | planner.enable_streamagg updated. |
> +-------+------------------------------------+
> 1 row selected (0.124 seconds)
> 0: jdbc:drill:schema=dfs> select * from dfs.tmp.bof_repro_2;
> +------------------+----------+
> | MYCOL | Bucket |
> +------------------+----------+
> | ["hello","hai"] | Bucket1 |
> | null | Bucket1 |
> +------------------+----------+
> 2 rows selected (0.247 seconds)
> 0: jdbc:drill:schema=dfs> select bucket, count(*) from dfs.tmp.bof_repro_2 group by bucket;
> Error: UNSUPPORTED_OPERATION ERROR: Hash aggregate does not support schema changes
> Fragment 0:0
> [Error Id: 60f8ada3-5f00-4413-a676-4881fc8cb409 on naravm3:31010] (state=,code=0)
> {code}
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