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https://issues.apache.org/jira/browse/HIVE-10746?page=com.atlassian.jira.plugin.system.issuetabpanels:comment-tabpanel&focusedCommentId=14555456#comment-14555456
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Greg Senia commented on HIVE-10746:
-----------------------------------
After having offline discussion with Gopal V he determined the cause of this
problem is that starting in Hive 0.14 org.apache.hadoop.mapred.TextInputFormat
uses whatever is defined in property:
mapreduce.input.fileinputformat.split.minsize; In my case this was defined to
"1"... Unfortunately that is 1 byte so it created 40040 splits creating 40400
reads of the single 3MB file...
Hope this helps someone else out.
Should be around half of the HDFS block size in my case 64MB since my block
size is 128MB..
mapreduce.input.fileinputformat.split.minsize=67108864
Gopal V if no fix is coming should we resolve/close this JIRA?
> Hive 0.14.x and Hive 1.2.0 w/ Tez 0.5.3/Tez 0.6.0 Slow group by/order by
> ------------------------------------------------------------------------
>
> Key: HIVE-10746
> URL: https://issues.apache.org/jira/browse/HIVE-10746
> Project: Hive
> Issue Type: Bug
> Components: Hive, Tez
> Affects Versions: 0.14.0, 0.14.1, 1.2.0, 1.1.0, 1.1.1
> Reporter: Greg Senia
> Priority: Critical
> Attachments: slow_query_output.zip
>
>
> The following query: "SELECT appl_user_id, arsn_cd, COUNT(*) as RecordCount
> FROM adw.crc_arsn GROUP BY appl_user_id,arsn_cd ORDER BY appl_user_id;" runs
> consistently fast in Spark and Mapreduce on Hive 1.2.0. When attempting to
> run this same query against Tez as the execution engine it consistently runs
> for over 300-500 seconds this seems extremely long. This is a basic external
> table delimited by tabs and is a single file in a folder. In Hive 0.13 this
> query with Tez runs fast and I tested with Hive 0.14, 0.14.1/1.0.0 and now
> Hive 1.2.0 and there clearly is something going awry with Hive w/Tez as an
> execution engine with Single or small file tables. I can attach further logs
> if someone needs them for deeper analysis.
> HDFS Output:
> hadoop fs -ls /example_dw/crc/arsn
> Found 2 items
> -rwxr-x--- 6 loaduser hadoopusers 0 2015-05-17 20:03
> /example_dw/crc/arsn/_SUCCESS
> -rwxr-x--- 6 loaduser hadoopusers 3883880 2015-05-17 20:03
> /example_dw/crc/arsn/part-m-00000
> Hive Table Describe:
> hive> describe formatted crc_arsn;
> OK
> # col_name data_type comment
>
> arsn_cd string
> clmlvl_cd string
> arclss_cd string
> arclssg_cd string
> arsn_prcsr_rmk_ind string
> arsn_mbr_rspns_ind string
> savtyp_cd string
> arsn_eff_dt string
> arsn_exp_dt string
> arsn_pstd_dts string
> arsn_lstupd_dts string
> arsn_updrsn_txt string
> appl_user_id string
> arsntyp_cd string
> pre_d_indicator string
> arsn_display_txt string
> arstat_cd string
> arsn_tracking_no string
> arsn_cstspcfc_ind string
> arsn_mstr_rcrd_ind string
> state_specific_ind string
> region_specific_in string
> arsn_dpndnt_cd string
> unit_adjustment_in string
> arsn_mbr_only_ind string
> arsn_qrmb_ind string
>
> # Detailed Table Information
> Database: adw
> Owner: [email protected]
> CreateTime: Mon Apr 28 13:28:05 EDT 2014
> LastAccessTime: UNKNOWN
> Protect Mode: None
> Retention: 0
> Location: hdfs://xhadnnm1p.example.com:8020/example_dw/crc/arsn
>
> Table Type: EXTERNAL_TABLE
> Table Parameters:
> EXTERNAL TRUE
> transient_lastDdlTime 1398706085
>
> # Storage Information
> SerDe Library: org.apache.hadoop.hive.serde2.lazy.LazySimpleSerDe
>
> InputFormat: org.apache.hadoop.mapred.TextInputFormat
> OutputFormat:
> org.apache.hadoop.hive.ql.io.HiveIgnoreKeyTextOutputFormat
> Compressed: No
> Num Buckets: -1
> Bucket Columns: []
> Sort Columns: []
> Storage Desc Params:
> field.delim \t
> line.delim \n
> serialization.format \t
> Time taken: 1.245 seconds, Fetched: 54 row(s)
> Explain Hive 1.2.0 w/Tez:
> STAGE DEPENDENCIES:
> Stage-1 is a root stage
> Stage-0 depends on stages: Stage-1
> STAGE PLANS:
> Stage: Stage-1
> Tez
> Edges:
> Reducer 2 <- Map 1 (SIMPLE_EDGE)
> Reducer 3 <- Reducer 2 (SIMPLE_EDGE)
> Explain Hive 0.13 w/Tez:
> STAGE DEPENDENCIES:
> Stage-1 is a root stage
> Stage-0 is a root stage
> STAGE PLANS:
> Stage: Stage-1
> Tez
> Edges:
> Reducer 2 <- Map 1 (SIMPLE_EDGE)
> Reducer 3 <- Reducer 2 (SIMPLE_EDGE)
> Results:
> Hive 1.2.0 w/Spark 1.3.1:
> Finished successfully in 7.09 seconds
> Hive 1.2.0 w/Mapreduce:
> Stage 1: 32 Seconds
> Stage 2: 35 Seconds
> Hive 1.2.0 w/Tez 0.5.3:
> Time taken: 565.025 seconds, Fetched: 11516 row(s)
>
> Hive 0.13 w/Tez 0.4.0:
> Time taken: 13.552 seconds, Fetched: 11516 row(s)
> And finally looking at the Dag Attempt that is stuck for 500 seconds or so in
> Tez it looks to be stuck running the same method over and over again:
> 8 duration=2561 from=org.apache.hadoop.hive.ql.exec.tez.RecordProcessor>
> 2015-05-18 19:58:41,719 INFO [TezChild] exec.Utilities: PLAN PATH =
> hdfs://xhadnnm1p.example.com:8020/tmp/hive/gss2002/dbc4b0b5-7859-4487-a56d-969440bc5e90/hive_2015-05-18_19-58-25_951_5497535752804149087-1/gss2002/_tez_scratch_dir/4e635121-c4cd-4e3f-b96b-9f08a6a7bf5d/map.xml
> 2015-05-18 19:58:41,822 INFO [TezChild] exec.MapOperator: MAP[4]: records
> read - 1
> 2015-05-18 19:58:41,835 INFO [TezChild] io.HiveContextAwareRecordReader:
> Processing file
> hdfs://xhadnnm1p.example.com:8020/example_dw/crc/arsn/part-m-00000
> 2015-05-18 19:58:41,848 INFO [TezChild] io.HiveContextAwareRecordReader:
> Processing file
> hdfs://xhadnnm1p.example.com:8020/example_dw/crc/arsn/part-m-00000
> ......
> 2015-05-18 20:07:46,560 INFO [TezChild] io.HiveContextAwareRecordReader:
> Processing file
> hdfs://xhadnnm1p.example.com:8020/example_dw/crc/arsn/part-m-00000
> 2015-05-18 20:07:46,574 INFO [TezChild] io.HiveContextAwareRecordReader:
> Processing file
> hdfs://xhadnnm1p.example.com:8020/example_dw/crc/arsn/part-m-00000
> 2015-05-18 20:07:46,587 INFO [TezChild] io.HiveContextAwareRecordReader:
> Processing file
> hdfs://xhadnnm1p.example.com:8020/example_dw/crc/arsn/part-m-00000
> 2015-05-18 20:07:46,603 INFO [TezChild] io.HiveContextAwareRecordReader:
> Processing file
> hdfs://xhadnnm1p.example.com:8020/example_dw/crc/arsn/part-m-00000
> 2015-05-18 20:07:46,603 INFO [TezChild] log.PerfLogger: </PERFLOG
> method=TezRunProcessor start=1431993518764 end=1431994066603 duration=547839
> from=org.apache.hadoop.hive.ql.exec.tez.TezProcessor>
> 2015-05-18 20:07:46,603 INFO [TezChild] exec.MapOperator: 4 finished.
> closing...
> 2015-05-18 20:07:46,603 INFO [TezChild] exec.MapOperator:
> RECORDS_IN_Map_1:13440
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