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Posted to issues-all@impala.apache.org by "Noemi Pap-Takacs (Jira)" <ji...@apache.org> on 2023/04/03 13:10:00 UTC

[jira] [Updated] (IMPALA-4530) Sort node after exchange should start sorting after first RowBatch is received

     [ https://issues.apache.org/jira/browse/IMPALA-4530?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]

Noemi Pap-Takacs updated IMPALA-4530:
-------------------------------------
    Affects Version/s:     (was: Impala 2.8.0)
               Labels: performance  (was: )
             Priority: Major  (was: Minor)

> Sort node after exchange should start sorting after first RowBatch is received
> ------------------------------------------------------------------------------
>
>                 Key: IMPALA-4530
>                 URL: https://issues.apache.org/jira/browse/IMPALA-4530
>             Project: IMPALA
>          Issue Type: Bug
>          Components: Backend
>            Reporter: Mostafa Mokhtar
>            Assignee: Noemi Pap-Takacs
>            Priority: Major
>              Labels: performance
>
> Sort node after exchange doesn't start sorting until all data is received which add lots of latency to the query. 
> Not clear if this optimization would still make sense for a Scan followed by a sort run using the same thread. 
> Query
> {code}
> insert into tpcds_1000_parquet.store_sales_insert  partition(ss_sold_date_sk, ss_quantity)  /*+ clustered*/
> select
> ss_sold_time_sk,
>   ss_item_sk ,
>   ss_customer_sk,
>   ss_cdemo_sk,
>   ss_hdemo_sk,
>   ss_addr_sk,
>   ss_store_sk,
>   ss_promo_sk,
>   ss_ticket_number ,
>   ss_wholesale_cost ,
>   ss_list_price ,
>   ss_sales_price ,
>   ss_ext_discount_amt ,
>   ss_ext_sales_price ,
>   ss_ext_wholesale_cost ,
>   ss_ext_list_price ,
>   ss_ext_tax ,
>   ss_coupon_amt ,
>   ss_net_paid ,
>   ss_net_paid_inc_tax ,
>   ss_net_profit,
>   ss_sold_date_sk  , ss_quantity
> from   store_sales
> {code}
> Plan
> {code}
> WRITE TO HDFS [tpcds_1000_parquet.store_sales_insert, OVERWRITE=false, PARTITION-KEYS=(ss_sold_date_sk,ss_quantity)]
> |  partitions=180576
> |  hosts=15 per-host-mem=17.88GB
> |
> 02:SORT
> |  order by: ss_sold_date_sk DESC NULLS LAST, ss_quantity DESC NULLS LAST
> |  hosts=15 per-host-mem=1.45GB
> |  tuple-ids=1 row-size=100B cardinality=2879987999
> |
> 01:EXCHANGE [HASH(ss_sold_date_sk,ss_quantity)]
> |  hosts=15 per-host-mem=0B
> |  tuple-ids=0 row-size=100B cardinality=2879987999
> |
> 00:SCAN HDFS [tpcds_1000_parquet.store_sales, RANDOM]
>    partitions=1824/1824 files=1824 size=189.24GB
>    table stats: 2879987999 rows total
>    column stats: all
>    hosts=15 per-host-mem=88.00MB
>    tuple-ids=0 row-size=100B cardinality=2879987999
> {code}



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