tumbling trigger

Question

tumbling trigger

Vineet S 1,390

The tumbling trigger is created to trigger and copy files from location A for every 5 mins if any files modified... but even there is no files modified in Location A (Source) , it is refreshing the modified date at Location B (Target) where the files are moving

Location A----- Copy

Location ----B ---Paste

issue even no change ... it is modifying modifed date files at B

Anonymous

2024-03-12T10:24:19.4733333+00:00
Hi @Vineet S

Thanks for reaching out to Microsoft Q&A.

You're right, a tumbling trigger firing every 5 minutes shouldn't necessarily modify the timestamp of files at the destination (Location B) if there are no changes in the source (Location A).

Here's a breakdown of the potential issue and solutions:

Possible Causes:

Copy Operation Behavior: The copy operation itself might be modifying the destination file's metadata (like timestamps) even if the content remains unchanged. This could be due to the specific tool or script used for copying.

File Permissions: Insufficient write permissions at the destination could lead to the file being recreated each time, resulting in a new timestamp.

Solutions:

Conditional Copy: Implement logic within the copy process to only copy files that have actually been modified since the last trigger. This can be achieved by:

Checking the source file's modification time before copying.

Using tools that support incremental copy, which only transfer the changed parts of the file.

Adjust Copy Operation: If the issue lies with the copy tool, explore alternative tools that preserve timestamps for unchanged files.

File Permissions: Ensure the copy process has the necessary permissions to modify the existing file at the destination without recreating it.

Logging: Implement logging to track file modifications and identify unnecessary copy operations

.Review Trigger Configuration: Double-check the trigger settings to ensure it's not forcing a full copy every time, even for unchanged files.

By implementing these solutions, you can prevent the destination file timestamps from being unnecessarily modified when there are no actual changes in the source files.

Azure Data Factory Tumbling Window Triggers: https://learn.microsoft.com/en-us/azure/data-factory/how-to-create-tumbling-window-trigger

Hope this helps. Do let us know if you any further queries.
Vineet S 1,390 Reputation points

2024-03-12T10:39:09.8+00:00

Can you give this step Conditional Copy: Implement logic within the copy process to only copy files that have actually been modified since the last trigger. This can be achieved by: Checking the source
Anonymous

2024-03-13T10:17:28.9566667+00:00
@Vineet S .Here's a breakdown of the conditional copy process with the logic to only copy modified files:

1. Accessing File Metadata:

Source File: Utilize the appropriate method (depending on the programming language or tool used) to access the source file's last modified timestamp. Examples:

Python: os.path.getmtime(source_file_path)

Linux/macOS: stat -c %y source_file

Windows: Libraries like os.stat or pre-built functions can be used.

2. Accessing Target File Metadata (Optional):

This step depends on your desired behavior:

Skip if Target Doesn't Exist: If the target file doesn't exist, a copy is always necessary.

Check for Modification: If the target file exists, compare its last modified timestamp with the source file's timestamp.

3. Conditional Logic:

Comparison: Compare the source file's last modified timestamp with:

No Target File: If the target file doesn't exist, proceed with the copy.

Target Exists: If the target file exists, compare its timestamp.

Source Newer: If the source file's timestamp is newer than the target's, proceed with the copy.

Source Older/Equal: No copy is needed.

4. Copy Operation (if applicable):

Based on the comparison results: Modified File: Initiate the copy process using the appropriate method (e.g., shutil.copy2 in Python, system commands like cp).

Example (Python):

import os def conditional_copy(source_file, target_file): """ Copies a file only if it has been modified since the last copy. Args: source_file: Path to the source file. target_file: Path to the target file. """ source_mtime = os.path.getmtime(source_file) # Check if target exists if not os.path.exists(target_file): # Target doesn't exist, copy the file shutil.copy2(source_file, target_file) return target_mtime = os.path.getmtime(target_file) # Compare timestamps if source_mtime > target_mtime: # Source is newer, copy the file shutil.copy2(source_file, target_file) print(f"Copied {source_file} to {target_file}") # Example usage source_file = "/path/to/source.txt" target_file = "/path/to/target.txt" conditional_copy(source_file, target_file)

Remember:

Adapt this code based on your specific programming language or tool.

Error handling (e.g., file not found) should be implemented for a robust solution.

This approach ensures that the copy process only occurs when the source file has been modified, preventing unnecessary updates to the target file's last modified date.
Vineet S 1,390 Reputation points

2024-03-14T00:20:43.6966667+00:00

can you please explain in adf pipeline

Answer accepted by question author

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Anonymous

2024-03-12T10:24:19.4733333+00:00

Hi @Vineet S

Thanks for reaching out to Microsoft Q&A.

You're right, a tumbling trigger firing every 5 minutes shouldn't necessarily modify the timestamp of files at the destination (Location B) if there are no changes in the source (Location A).

Here's a breakdown of the potential issue and solutions:

Possible Causes:

Copy Operation Behavior: The copy operation itself might be modifying the destination file's metadata (like timestamps) even if the content remains unchanged. This could be due to the specific tool or script used for copying.

File Permissions: Insufficient write permissions at the destination could lead to the file being recreated each time, resulting in a new timestamp.

Solutions:

Conditional Copy: Implement logic within the copy process to only copy files that have actually been modified since the last trigger. This can be achieved by:

Checking the source file's modification time before copying.

Using tools that support incremental copy, which only transfer the changed parts of the file.

Adjust Copy Operation: If the issue lies with the copy tool, explore alternative tools that preserve timestamps for unchanged files.

File Permissions: Ensure the copy process has the necessary permissions to modify the existing file at the destination without recreating it.

Logging: Implement logging to track file modifications and identify unnecessary copy operations

.Review Trigger Configuration: Double-check the trigger settings to ensure it's not forcing a full copy every time, even for unchanged files.

By implementing these solutions, you can prevent the destination file timestamps from being unnecessarily modified when there are no actual changes in the source files.

Azure Data Factory Tumbling Window Triggers: https://learn.microsoft.com/en-us/azure/data-factory/how-to-create-tumbling-window-trigger

Hope this helps. Do let us know if you any further queries.
Vineet S 1,390 Reputation points

2024-03-12T10:39:09.8+00:00

Can you give this step Conditional Copy: Implement logic within the copy process to only copy files that have actually been modified since the last trigger. This can be achieved by: Checking the source
Vineet S 1,390 Reputation points

2024-03-14T00:20:43.6966667+00:00

can you please explain in adf pipeline

Answer 1

Hi Vineet,

Here’s a high-level overview of how you can create an Azure Data Factory (ADF) pipeline to copy only modified data from Source A to Source B using a trigger that runs every 5 minutes.

Create Linked Services: Create linked services in ADF for both Source A and Source B. These linked services will act as connection strings to your data sources.
Create Datasets: Create datasets for Source A and Source B. These datasets represent the structure of your data.
Create a Pipeline: Create a new pipeline in ADF.
Add a Copy Activity: In your pipeline, add a ‘Copy Data’ activity. This activity will be responsible for copying the data from Source A to Source B.
Configure the Copy Activity: In the ‘Source’ tab of the copy activity, select the dataset for Source A. In the ‘Sink’ tab, select the dataset for Source B.
Incremental Load: To copy only the modified data, you need to set up an incremental load. This can be done by parameterizing your dataset to accept a ‘last modified’ timestamp. Then, in your copy activity, you can write a query to select only the rows where the ‘last modified’ timestamp is later than the parameter value.
Create a Trigger: Finally, create a new trigger that runs every 5 minutes. Attach this trigger to your pipeline.

Here’s a sample code snippet for the Copy Activity with incremental load:

User's image

Please replace [SourceA], [last_modified] with your actual table name and column name.

Remember to replace the sqlReaderQuery and type in both source and sink based on your actual data source and destination type.

This is a high-level overview and the actual implementation might vary based on the specifics of your data sources and requirements. You might want to refer to the official Azure Data Factory documentation for more detailed steps and instructions.

If you find my answer helpful, please consider marking it as the ‘Answer’ and giving it an ‘Upvote’ using the thumbs-up option. This can also benefit other community members who may have the same question.

Thanks,

Karni.G

P.S. - The answer was generated with the help of Co-Pilot.

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