So you union two tables, union the result with another one, and finally with a last one?

How many columns do all these tables have?

Are you sure creating the plan depends on the number of rows?

Enrico


Am 22.02.23 um 19:08 schrieb Prem Sahoo:
here is the information missed
1. Spark 3.2.0
2. it is scala based
3. size of tables will be ~60G
4. explain plan for catalysts shows lots of time is being spent in creating the plan
5. number of union table is 2 , and another 2 then finally 2

slowness is providing resylut as the data size & column size increases .

On Wed, Feb 22, 2023 at 11:07 AM Enrico Minack <i...@enrico.minack.dev> wrote:

    Plus number of unioned tables would be helpful, as well as which
    downstream operations are performed on the unioned tables.

    And what "performance issues" do you exactly measure?

    Enrico



    Am 22.02.23 um 16:50 schrieb Mich Talebzadeh:
    Hi,

    Few details will help

     1. Spark version
     2. Spark SQL, Scala or PySpark
     3. size of tables in join.
     4. What does explain() or the joining operation show?


    HTH


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    On Wed, 22 Feb 2023 at 15:42, Prem Sahoo <prem.re...@gmail.com>
    wrote:

        Hello Team,
        We are observing Spark Union performance issues when unioning
        big tables with lots of rows. Do we have any option apart
        from the Union ?


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