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Posted to issues@hive.apache.org by "Matt McCline (JIRA)" <ji...@apache.org> on 2015/11/26 03:34:11 UTC
[jira] [Resolved] (HIVE-9983) Vectorizer doesn't vectorize (1)
partitions with different schema anywhere (2) any MapWork with >1 table
scans in MR
[ https://issues.apache.org/jira/browse/HIVE-9983?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Matt McCline resolved HIVE-9983.
--------------------------------
Resolution: Won't Fix
> Vectorizer doesn't vectorize (1) partitions with different schema anywhere (2) any MapWork with >1 table scans in MR
> --------------------------------------------------------------------------------------------------------------------
>
> Key: HIVE-9983
> URL: https://issues.apache.org/jira/browse/HIVE-9983
> Project: Hive
> Issue Type: Bug
> Components: Vectorization
> Reporter: Sergey Shelukhin
> Assignee: Matt McCline
>
> For some test, tables are created as such:
> {noformat}
> CREATE TABLE orc_llap_part(
> csmallint SMALLINT,
> cint INT,
> cbigint BIGINT,
> cfloat FLOAT,
> cdouble DOUBLE,
> cstring1 STRING,
> cstring2 STRING,
> ctimestamp1 TIMESTAMP,
> ctimestamp2 TIMESTAMP,
> cboolean1 BOOLEAN,
> cboolean2 BOOLEAN
> ) PARTITIONED BY (ctinyint TINYINT) STORED AS ORC;
> CREATE TABLE orc_llap_dim_part(
> cbigint BIGINT
> ) PARTITIONED BY (ctinyint TINYINT) STORED AS ORC;
> INSERT OVERWRITE TABLE orc_llap_part PARTITION (ctinyint)
> SELECT csmallint, cint, cbigint, cfloat, cdouble, cstring1, cstring2, ctimestamp1, ctimestamp2, cboolean1, cboolean2, ctinyint FROM alltypesorc;
> INSERT OVERWRITE TABLE orc_llap_dim_part PARTITION (ctinyint)
> SELECT sum(cbigint) as cbigint, ctinyint FROM alltypesorc WHERE ctinyint > 10 AND ctinyint < 21 GROUP BY ctinyint;
> {noformat}
> The query is:
> {noformat}
> explain
> SELECT oft.ctinyint, oft.cint FROM orc_llap_part oft
> INNER JOIN orc_llap_dim_part od ON oft.ctinyint = od.ctinyint;
> {noformat}
> This results in a failure to vectorize in MR:
> {noformat}
> Could not vectorize partition pfile:/Users/sergey/git/hive3/itests/qtest/target/warehouse/orc_llap_dim_part/ctinyint=11. Its column names cbigint do not match the other column names csmallint,cint,cbigint,cfloat,cdouble,cstring1,cstring2,ctimestamp1,ctimestamp2,cboolean1,cboolean2
> {noformat}
> This is comparing schemas from different tables because MapWork has 2 TableScan-s; in Tez this error will never happen as MapWork will not have 2 scans.
> In Tez (and MR as well), the other case can happen, namely partitions of the same table having different schemas.
> Tez case can be solved by making a super-schema to include all variations and handling missing columns where necessary.
> MR case may be harder to solve.
> Of note is that despite schema being different (and not a prefix of a schema by coincidence or some such), query passes if validation is commented out. Perhaps in some cases it can work?
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