[Storage] Adjust default connection_data_block_size for all Storage packages
#44332
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jalauzon-msft
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annatisch,
vincenttran-msft and
weirongw23-msft
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Pull request overview
This PR increases the default connection_data_block_size from 4 KiB to 256 KiB across all Azure Storage SDK packages based on performance testing that showed significant speed improvements for large file downloads with minimal resource impact.
- Adds a new constant
DATA_BLOCK_SIZE = 256 * 1024to shared constants in all storage packages - Sets this value as the default for
connection_data_block_sizein the pipeline configuration - Updates comment from "Default socket timeouts, in seconds" to "Connection defaults" to reflect the broader scope
Reviewed changes
Copilot reviewed 12 out of 12 changed files in this pull request and generated no comments.
Show a summary per file
| File | Description |
|---|---|
| sdk/storage/azure-storage-queue/azure/storage/queue/_shared/constants.py | Adds DATA_BLOCK_SIZE constant (256 KiB) and updates comment to "Connection defaults" |
| sdk/storage/azure-storage-queue/azure/storage/queue/_shared/base_client_async.py | Imports DATA_BLOCK_SIZE and sets it as default for connection_data_block_size |
| sdk/storage/azure-storage-queue/azure/storage/queue/_shared/base_client.py | Imports DATA_BLOCK_SIZE and sets it as default for connection_data_block_size |
| sdk/storage/azure-storage-file-share/azure/storage/fileshare/_shared/constants.py | Adds DATA_BLOCK_SIZE constant (256 KiB) and updates comment to "Connection defaults" |
| sdk/storage/azure-storage-file-share/azure/storage/fileshare/_shared/base_client_async.py | Imports DATA_BLOCK_SIZE and sets it as default for connection_data_block_size |
| sdk/storage/azure-storage-file-share/azure/storage/fileshare/_shared/base_client.py | Imports DATA_BLOCK_SIZE and sets it as default for connection_data_block_size |
| sdk/storage/azure-storage-file-datalake/azure/storage/filedatalake/_shared/constants.py | Adds DATA_BLOCK_SIZE constant (256 KiB) and updates comment to "Connection defaults" |
| sdk/storage/azure-storage-file-datalake/azure/storage/filedatalake/_shared/base_client_async.py | Imports DATA_BLOCK_SIZE and sets it as default for connection_data_block_size |
| sdk/storage/azure-storage-file-datalake/azure/storage/filedatalake/_shared/base_client.py | Imports DATA_BLOCK_SIZE and sets it as default for connection_data_block_size |
| sdk/storage/azure-storage-blob/azure/storage/blob/_shared/constants.py | Adds DATA_BLOCK_SIZE constant (256 KiB) and updates comment to "Connection defaults" |
| sdk/storage/azure-storage-blob/azure/storage/blob/_shared/base_client_async.py | Imports DATA_BLOCK_SIZE and sets it as default for connection_data_block_size |
| sdk/storage/azure-storage-blob/azure/storage/blob/_shared/base_client.py | Imports DATA_BLOCK_SIZE and sets it as default for connection_data_block_size |
Member
|
This looks great! The analyzer failure is coming from Queue package's Black formatter so it should be simple :) |
weirongw23-msft
approved these changes
Dec 9, 2025
weirongw23-msft
approved these changes
Dec 9, 2025
jalauzon-msft
added a commit
to jalauzon-msft/azure-sdk-for-python
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this pull request
Dec 10, 2025
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Adjusting the default
connection_data_block_sizeto 256 KiB for all Storage packages. The current default for this value is 4 KiB, and some perf testing has revealed that increasing this value can drastically increase the speed of large file downloads without much cost to CPU or memory. Many values were tested on a range of VM sizes, and 256 KiB was found to be a good default across all VM SKUs.