[Solved] SSIS data load from Oracle source is dramatically slow

EverSQL Database Performance Knowledge Base

SSIS data load from Oracle source is dramatically slow

Database type:

In my SSIS project I need sync data between Oracle and MS SQL.

MS VS 2017 32bit

MS SQL Server 2017 64bit

OLEDB Connector 32bit

The speed is 30 rows per 1 sec

  1. I deleted the target destinations and added just row counter. The same result.

  2. I did the DataFlow Setup: DefaultBufferMaxRows = 1000000 DefaultBufferSize = 104857600 The same result.

  3. I changed source SQL to:

    SELECT * FROM SourceTable ORDER BY LAST_UPDATE OFFSET 0 ROWS FETCH NEXT 10000 ROWS ONLY

The same result.

I read a lot of but people ask how to optimise 100K rows / 3 sec. :)

P.S. The same select work significantly faster from MS SQL Server:

SELECT * FROM OPENQUERY([ORASA], 'SELECT * FROM SourceTable ORDER BY LAST_UPDATE OFFSET 0 ROWS FETCH NEXT 10000 ROWS ONLY')

How to optimize this SQL query?

The following recommendations will help you in your SQL tuning process.
You'll find 3 sections below:

  1. Description of the steps you can take to speed up the query.
  2. The optimal indexes for this query, which you can copy and create in your database.
  3. An automatically re-written query you can copy and execute in your database.
The optimization process and recommendations:
  1. Avoid Selecting Unnecessary Columns (query line: 2): Avoid selecting all columns with the '*' wildcard, unless you intend to use them all. Selecting redundant columns may result in unnecessary performance degradation.
The optimized query:
SELECT
        * 
    FROM
        OPENQUERY([ORASA],
        'SELECT * FROM SourceTable ORDER BY LAST_UPDATE OFFSET 0 ROWS FETCH NEXT 10000 ROWS ONLY')

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* original question posted on StackOverflow here.