[Spark SQL]: Is it possible that spark SQL appends "SELECT 1 " to the query

[Ramakrishna Rayudu]

Hi Team,

I am facing one issue. Can you please help me on this.

<https://stackoverflow.com/>

   1.


<https://stackoverflow.com/posts/74477662/timeline>

We are connecting Tera data from spark SQL with below API

Dataset<Row> jdbcDF = spark.read().jdbc(connectionUrl, tableQuery,
connectionProperties);

when we execute above logic on large table with million rows every
time we are seeing below

extra query is executing every time as this resulting performance hit on DB.

This below information we got from DBA. We dont have any logs on SPARK SQL.

SELECT 1 FROM ONE_MILLION_ROWS_TABLE;

1
1
1
1
1
1
1
1
1

Can you please clarify why this query is executing or is there any chance
that this type of query is executing from our code it self while check for
rows count from dataframe.

Please provide me your inputs on this.


Thanks,

Rama