Datastream maxConcurrentCdcTasks

[NishinThattil]

We are using datastream to stream data from our oracle to bigquery database, at the time of month end there are a high number of redo logs generated on the source database.

Can you please help on how we can increase the maxConcurrentCdcTasks for the datastream.

[ms4446]

The maxConcurrentCdcTasks parameter in Google Cloud Datastream controls how many Change Data Capture (CDC) tasks run simultaneously. During periods of high database activity (e.g., increased redo logs from Oracle), raising this value helps Datastream process changes more efficiently.

Increasing maxConcurrentCdcTasks:

Google Cloud Console:

1. Go to your Datastream instance in the Google Cloud Console.
2. Select the specific stream to configure.
3. If available, find maxConcurrentCdcTasks under "Advanced Settings" in the "Stream Configuration" section. Edit it there.
4. If you cannot edit it directly in the console, use the gcloud CLI or REST API.

API (gcloud CLI or REST API):

Use the following gcloud command to update the parameter:

Bash

gcloud datastream streams update YOUR_STREAM_NAME \

  --location=YOUR_REGION \

  --update-mask="streamConfig.maxConcurrentCdcTasks" \

  --stream-config='{"maxConcurrentCdcTasks": NEW_VALUE}'

Replace placeholders with your stream's name, region, and desired new value.

Important Considerations:

• Oracle Database Resources: More concurrent CDC tasks increase database load. Make sure your Oracle database has enough CPU, memory, and I/O resources to handle this.
• Network Bandwidth: Increased parallelism means more network traffic between your database and Datastream.Ensure your network can handle it.
• Monitoring: Keep a close eye on Datastream metrics (replication lag, CPU usage) and Oracle database metrics (redo log generation, AWR reports). Adjust maxConcurrentCdcTasks as needed to balance performance and resource use.

Alternative Approaches:

If changing parallelism doesn't fix the issue, consider these:

• Stream Configuration Optimization: Adjust settings like batch size.
• Oracle Database Tuning: Reduce redo log generation during peak times.
• BigQuery Integration: Ensure efficient data handling, potentially using BigQuery's streaming insert feature.

[NishinThattil]

Getting error while executing the gcloud command 

gcloud datastream streams update YOUR_STREAM_NAME \

--location=YOUR_REGION \

--update-mask="streamConfig.maxConcurrentCdcTasks" \

--stream-config='{"maxConcurrentCdcTasks": NEW_VALUE}'

ERROR: (gcloud.datastream.streams.update) unrecognized arguments: --stream-config={"maxConcurrentCdcTasks": 10} (did you mean '--postgresql-source-config'?) 

[ms4446]

The error message you encountered indicates that there might be an issue with the syntax of the gcloud command, specifically regarding how the streamConfig is being updated. The gcloud datastream streams update command does not directly accept a --stream-config flag, which is why it's producing an "unrecognized arguments" error.

To resolve this, we should adjust the command to properly update the stream settings. Google Cloud's gcloud CLI often uses a JSON-like structure for complex configurations, but the exact flags and methods can vary based on the CLI version and specific service commands.

Let's try to structure the command correctly. If your goal is to update the maxConcurrentCdcTasks setting, you might need to pass this as part of a configuration update using a JSON snippet, but ensuring it's done with the correct flags:

gcloud datastream streams update YOUR_STREAM_NAME \ --location=YOUR_REGION \ --update-mask="streamConfiguration.maxConcurrentCdcTasks" \ --stream-configuration='{"maxConcurrentCdcTasks":NEW_VALUE}'

Make sure you replace YOUR_STREAM_NAME, YOUR_REGION, and NEW_VALUE with the actual stream name, the region your stream is located in, and the value you wish to set for maxConcurrentCdcTasks.

Note: Ensure your gcloud CLI is up to date as the commands and flags can change between versions. You can update it using:

gcloud components update

If this doesn't resolve the issue, it might be helpful to look at the specific syntax for the Datastream update command for your gcloud CLI version. You can check the documentation for the exact syntax or run:

gcloud datastream streams update --help

[NishinThattil]

The command is throwing error.

[ms4446]

If you're encountering errors with the syntax for updating maxConcurrentCdcTasks, it may be beneficial to revisit the correct usage of the gcloud command for Google Cloud Datastream.

Since the gcloud command to directly update specific settings like maxConcurrentCdcTasks seems to be throwing errors, here are the steps you can take to correctly form your command:

1. Verify Available Properties for Update:

   • First, ensure that the maxConcurrentCdcTasks is a valid configurable property via the CLI and check how it should be specified.

   • Use the --help flag on the update command to see the available options and the correct structure:

     gcloud datastream streams update --help

2. Use the Correct Flags and Structure:

   • The error message suggests the CLI does not recognize --stream-config or the property is not correctly addressed. We need to find the right way to specify stream configuration updates.

3. General Syntax for Updating Properties:

   • The general syntax for updating a resource in gcloud often involves specifying what exactly needs to be updated and then providing the new configuration in a JSON format if it's a complex nested property.

4. Check Documentation:

   • It's also advisable to check the latest online Google Cloud documentation for Datastream or any release notes for updates or changes in the CLI commands.

Since the exact command structure isn't working, and if the documentation or the --help command does not clarify the usage, you might consider using the Google Cloud Platform Console (if possible) or contacting Google Cloud support for more detailed guidance on how to update this particular setting via the CLI.

In case you need immediate assistance in modifying stream properties and are unable to resolve the CLI issues, using the Google Cloud Console might provide a more user-friendly interface to make the required changes, if the setting is exposed there. Additionally, checking if there's an available API call that can be used as an alternative to perform this update might be beneficial.