Forum Discussion
data loading is very slow from oracle Db using import
I'm trying to load the data from oracle to power bi desktop. Data is almost 5 M. For loading 2 lakhs of data it is taking 2.30 hrs of time in my desktop with selected columns. any suggestions to make the data load faster. Need to load total 5 M records to power bi.
HI Anonymous
How many columns are being loaded, and what's the cardinality of your data?
Columns with high cardinality — such as a datetime column where most values are unique — can significantly slow data loading, as they require more memory to encode and compress in Power BI's VertiPaq engine. Additionally, server-side performance plays a key role. If the Oracle server has limited resources, network latency, or slow I/O response times, it will also affect the speed at which data is retrieved and loaded.Hi Sergii24 and Sergii24 , thanks for your time with such thoughtful response. Really appreciate the way you both broke it down.
Anonymous , just to add on to their points, here are a few suggestions that helped in similar situations.
Thanks for the details. A few practical things you can try to speed up the data load.
- Filter During Import (if possible) – Even though you want all 5M rows eventually, try filtering only recent rows (like last 6 months) during development and remove the filter later. It helps reduce the load time while you're building the report.
- Use Native Query – Instead of loading the table directly in Power Query, write a custom SQL query to only pull the columns you need. This reduces overhead and avoids pulling unnecessary metadata.
- Check for Unnecessary Indexes or Triggers – If the Oracle table has any logging or triggers firing on read, it might slow things down. A DBA can help check that.
- Avoid Loading Complex Data Types – Columns like BLOBs, CLOBs, or high-cardinality fields (like timestamps with millisecond precision or GUIDs) are costly in VertiPaq. Try excluding them during import.
- Switch to OLE DB Connector (Optional) – Sometimes, the OLE DB connector performs better than the Oracle client. Worth testing if you're seeing consistently poor load times.
- Monitor Oracle Server Load – Use Oracle tools or ask your DBA to check if the server is bottlenecked during the load (CPU/disk/network).
Let us know how it goes once we identify the bottleneck, we can dig deeper into optimizations.
Regards,
Akhil.
7 Replies
Hi Sergii24 and Sergii24 , thanks for your time with such thoughtful response. Really appreciate the way you both broke it down.
Anonymous , just to add on to their points, here are a few suggestions that helped in similar situations.
Thanks for the details. A few practical things you can try to speed up the data load.
- Filter During Import (if possible) – Even though you want all 5M rows eventually, try filtering only recent rows (like last 6 months) during development and remove the filter later. It helps reduce the load time while you're building the report.
- Use Native Query – Instead of loading the table directly in Power Query, write a custom SQL query to only pull the columns you need. This reduces overhead and avoids pulling unnecessary metadata.
- Check for Unnecessary Indexes or Triggers – If the Oracle table has any logging or triggers firing on read, it might slow things down. A DBA can help check that.
- Avoid Loading Complex Data Types – Columns like BLOBs, CLOBs, or high-cardinality fields (like timestamps with millisecond precision or GUIDs) are costly in VertiPaq. Try excluding them during import.
- Switch to OLE DB Connector (Optional) – Sometimes, the OLE DB connector performs better than the Oracle client. Worth testing if you're seeing consistently poor load times.
- Monitor Oracle Server Load – Use Oracle tools or ask your DBA to check if the server is bottlenecked during the load (CPU/disk/network).
Let us know how it goes once we identify the bottleneck, we can dig deeper into optimizations.
Regards,
Akhil.- Sergii24
Super User
Hi Anonymous, unfortunately, there isn't enough information to help you... Please provide some more context. So I understand that you want to load 5 million records from your DB in Import mode. But do those 5M records come from the same single table in your Oracle DB? What connector do you use to connect to Oracle? What transformations do you perform in Power Query? Are there any other tables that you import in addition to this one?
Hi Sergii24 ,
Thank you for quick response.
5M records come from the same single table in your Oracle DB?----> yes,loading single table
What connector do you use to connect to Oracle? --->https://download.oracle.com/otn_software/odac/OracleClientForMicrosoftTools_x64_19.exe
What transformations do you perform in Power Query? ---> Nothing
Are there any other tables that you import in addition to this one? ----> No
Thanks in advance.
- danextian
HI Anonymous
How many columns are being loaded, and what's the cardinality of your data?
Columns with high cardinality — such as a datetime column where most values are unique — can significantly slow data loading, as they require more memory to encode and compress in Power BI's VertiPaq engine. Additionally, server-side performance plays a key role. If the Oracle server has limited resources, network latency, or slow I/O response times, it will also affect the speed at which data is retrieved and loaded. Hi Anonymous ,
Just checking in were you able to try out any of the suggestions shared by super users and the additional tips we mentioned earlier? To know if filtering during import or switching connectors made any noticeable difference in your load performance. If you're still running into issues or have narrowed down, feel free to share more details we'd be happy to dive deeper and help optimize further. Looking forward to your update.
Regards,
Akhil.Hi Anonymous,
Just looping back to see if you had a chance to try out any of the suggestions shared earlier by the super users especially around filtering during import or switching connectors. Did those make any noticeable difference in your data load performance? If you're still facing challenges or have more clarity on what’s causing the issue, feel free to share the details. We'd be more than happy to take a closer look and help you optimize things further.
Regards,
Akhil.Hi Anonymous ,
Since we haven’t heard back from you, we’ll proceed to close this thread for now. If you continue to experience issues or have any additional questions, feel free to start a new thread in the Microsoft Fabric Community Forum. We’re always here to help and happy to support you.
Regards,
Akhil.
