Redshift and the data.world Collector
Note
The latest version of the Collector is 2.137. To view the release notes for this version and all previous versions, please go here.
About the collector
Use this collector to harvest metadata for Redhsift tables and columns across the enterprise systems and make it searchable and discoverable in data.world.
Authentication supported
The collector supports basic authentication to Redshift.
What is cataloged
The collector catalogs the following information.
Object | Information cataloged |
|---|---|
Columns | Name, Description, JDBC type, Column Type, Is Nullable, Default Value, Key type (Primary, foreign), column size, column index |
Table | Name, description, primary key, schema |
Views | Name, description, SQL definition |
Schema | Identifier |
Database | Type, name, identifier, server, port, environment, JDBC URL |
Relationships between objects
By default, the harvested metadata includes catalog pages for the following resource types. Each catalog page has a relationship to the other related resource types. If the metadata presentation for this data source has been customized with the help of the data.world Solutions team, you may see other resource pages and relationships.
Resource page | Relationship |
|---|---|
Table | Columns |
Columns | Table |
Lineage for Redshift
The collector identifies, for every column in a View, the column(s) in other tables or views from which that view’s column selects (sources) its data.
The collector traces these relationships from a View’s columns to ultimate source Table columns across SQL expressions and subqueries.
Additionally, the collector establishes relationships between a View and any columns in source Tables that sort the rows in the View (via SQL ORDER BY), filter the rows in the View (via SQL WHERE and HAVING clauses), and aggregate the rows in the View (via SQL GROUP BY).
Note
Note that the collector currently does not establish view-to-table relationships in the JDBC collectors. This can be done transitively (e.g., in SPARQL) by noting the column-level relationships, since each column is associated with one and only one table or view.
Preparing Redshift for collectors
Make sure you download the appropriate JDBC driver for Redshift on the machine from where you will run the collector.
Setting up pre-requisites for running the collectors
Make sure that the machine from where you are running the collector meets the following hardware and software requirements.
Item | Requirement |
|---|---|
Hardware | |
RAM | 8 GB |
CPU | 2 Ghz processor |
Software | |
Docker | Click here to get Docker. |
Java Runtime Environment | OpenJDK 17 is supported and available here. |
JDBC Driver | The computer should have the appropriate JDBC driver on its file system. |
data.world specific objects | |
Dataset | You must have a ddw-catalogs (or other) dataset set up to hold your catalog files when you are done running the collector. |
Generating the command and YAML file
This section walks you through the process of generating the command or YAML file for running the collector from Windows or Linux or MAC OS.
To generate the command or YAML file:
On the Organization profile page, go to the Settings tab > Metadata collectors section.
Click the Help me set up a collector button.
On the On-prem collector setup prerequisites screen, read the pre-requisites and click Next.
On the On which platform will this collector execute? screen, select if you will be running the collector on Windows or Mac OS or Linux. This will determine the format of the YAML and CLI that is generated in the end. Click Next.
On the Choose metadata collector type you would like to setup screen, select Redshift. Click Next.
On the Redshift Collector requires an additional driver file screen, set the following and Click Next.
Table 3.Field name
Corresponding parameter name
Description
Required?
JDBC driver directory
source=${HOME}/dwcc-drivers
The driver required to run the collector. You must download this driver yourself and place it in a directory on the machine that will run the collector.
Yes
On the Configure a new on premises Redshift Collector screen, set the following properties and click Next.
On the next screen, set the following properties and click Next.
Table 5.Field name
Corresponding parameter name
Description
Required
Server
-s=<server>
--server=<server>
The hostname of the database server to connect to.
Yes
Server port
-p=<port>
--port=<port>
The port of the database server (if not the default).
No
Database
-d=<database>
--database=<database>
The name of the database to connect to.
Yes
Database Id
-D=<databseid>
database-id=<databaseId>
A unique identifier for this database - will be used to generate the ID for the database (this is optional, you only need to provide this if the database name used for the connection is not sufficiently unique to completely identify the database)
No
Schemas to collect
Select from one of the following options: Collect all schema, Specify which schema to collect
Yes
Collect all schema
-A --all-schemas
Catalog all schemas to which the user has access.
Yes (if --schema is not set)
Specify which schema to collect
-S=<databaseSchema>
--schema=<databaseSchema>
The name of the database schema to catalog.
Yes (if --all-schema is not set)
Information schema
--include-information-schema
When --all-schemas is specified, include the database's Information Schema in catalog collection (ignored if --all-schemas is not specified).
No
Username
-u=<user>
--user=<user>
The username to use to connect to the database.
Yes
Password
-P=<password>
--password=<password>
The environment variable of the password used to connect to the database.
Yes
Server Environment
-e=<environment>
--environment=<environment>
If your provided server name is localhost, use this to give a friendly name to the environment in which your database server runs to help differentiate it from other environments.
No
On the next screen, set the following optional properties and click Next.
Table 6.Field name
Corresponding parameter name
Description
Required?
Disable lineage collection
--disable-lineage-collection
Skip harvesting of intra-database lineage metadata.
No
Enable column statistics collection
--enable-column-statistics
To enable harvesting of column statistics (i.e., data profiling)
No
Enable sample string values collection
--sample-string-values
to enable harvesting of sample values and histograms for columns containing string data
No
Target sample size for Profiling
--target-sample-size=<targetSampleSize>
To control the number of rows sampled for computation of column statistics and string-value histograms. For example, to sample 1000 rows, set the parameter as: --target-sample-size=1000
No
JDBC Properties
--jdbc-property=<driverProperties>
JDBC driver properties to pass through to driver connection.
No
On the Finalize your Redshift Collector configuration screen, you are notified about the environment variables and directories you need to setup for running the collector. Select if you want to generate Configuration file ( YAML) or Command line arguments (CLI). Click Next.
Important
You must ensure that you have set up these environment variables and directories before you run the collector.
The next screen gives you an option to download the YAML configuration file or copy the CLI command. Click Done. If you are generating a YAML file, click Next.
Sample YAML file.
The Redshift command screen gives you the command to use for running the collector using the YAML file.
You will notice that the YAML/CLI has following additional parameters that are automatically set for you.
Important
Except for the collector version, you should not change the values of any of the parameter listed here.
Table 7.Parameter name
Details
Required?
-a= <agent>
--agent= <agent>
--account= <agent>
The ID for the data.world account into which you will load this catalog - this is used to generate the namespace for any URIs generated.
Yes
--site= <site>
This parameter should be set only for Private instances. Do not set it for public instances and single-tenant installations. Required for private instance installations.
Yes (required for private instance installations)
-U
--upload
Whether to upload the generated catalog to the organization account's catalogs dataset.
Yes
-L
--no-log-upload
Do not upload the log of the Collector run to the organization account's catalogs dataset.
Yes
dwcc: <CollectorVersion>
The version of the collector you want to use (For example,
datadotworld/dwcc:2.113)Yes
Add the following additional parameter to test run the collector.
--dry-run If specified, the collector does not actually harvest any metadata, but just checks the database connection parameters provided by the user and reports success or failure at connecting.
Verifying environment variables and directories
Verify that you have set up all the required environment variables that were identified by the Collector Wizard before running the collector. Alternatively, you can set these credentials in a credential vault and use a script to retrieve those credentials.
Verify that you have set up all the required directories that were identified by the Collector Wizard.
Running the collector
Important
Before you begin running the collector make sure you have the correct version of collectors downloaded and available.
Running collector using YAML file
Go to the server where you have setup docker to run the collector.
Make sure you have download the correct version of collectors. This version should match the version of the collector specified in the command you are using to run the collector.
Place the YAML file generated from the Collector wizard to the correct directory.
From the command line, run the command generated from the application for executing the YAML file.
Caution
Note that is just a sample command for showing the syntax. You must generate the command specific to your setup from the application UI.
docker run -it --rm --mount type=bind,source=${HOME}/dwcc,target=/dwcc-output \ --mount type=bind,source=${HOME}/dwcc,target=${HOME}/dwcc --mount type=bind,source=${HOME}/dwcc-drivers,target=/usr/src/dwcc-config/lib \ -e DW_AUTH_TOKEN=${DW_AUTH_TOKEN} -e DW_REDSHIFT_PASSWORD=${DW_REDSHIFT_PASSWORD} \ datadotworld/dwcc:2.124 --config-file=/dwcc-output/config-redshift.ymlThe collector automatically uploads the file to the specified dataset and you can also find the output at the location you specified while running the collector.
At a later point, if you download a newer version of collector from Docker, you can edit the collector version in the generated command to run the collector with the newer version.
Running collector without the YAML file
Go to the server where you have setup docker to run the collector.
Make sure you have download the version of collectors from here. This version should match the version of the collector specified in the command you are using to run the collector.
From the command line, run the command generated from the application. Here is a sample command.
Caution
Note that is just a sample command for showing the syntax. You must generate the command specific to your setup from the application UI.
docker run -it --rm --mount type=bind,source=${HOME}/dwcc,target=/dwcc-output \ --mount type=bind,source=${HOME}/dwcc,target=${HOME}/dwcc --mount type=bind,source=${HOME}/dwcc-drivers,target=/usr/src/dwcc-config/lib \ datadotworld/dwcc:2.124 catalog-redshift --agent=8bank-catalog-sources \ --site=solutions --no-log-upload=false --upload=true --api-token=${DW_AUTH_TOKEN} \ --output=/dwcc-output --name=8bank-catalog-sources-collection \ --upload-location=ddw-catalogs --server=8bank-server --database=8bank-database \ --all-schemas=true --include-information-schema=false --user=8bank-username \ --password=${DW_REDSHIFT_PASSWORD} --disable-lineage-collection=false \ --enable-column-statistics=true --sample-string-values=true --target-sample-size=10The collector automatically uploads the file to the specified dataset and you can also find the output at the location you specified while running the collector.
At a later point, if you download a newer version of collector from Docker, you can edit the collector version in the generated command to run the collector with the newer version.
Collector runtime and troubleshooting
The catalog collector may run in several seconds to many minutes depending on the size and complexity of the system being crawled. If the catalog collector runs without issues, you should see no output on the terminal, but a new file that matching *.dwec.ttl should be in the directory you specified for the output. If there was an issue connecting or running the catalog collector, there will be either a stack trace or a *.log file. Both of those can be sent to support to investigate if the errors are not clear. A list of common issues and problems encountered when running the collectors is available here.
Automating updates to your metadata catalog
Keep your metadata catalog up to date using cron, your Docker container, or your automation tool of choice to run the catalog collector on a regular basis. Considerations for how often to schedule include:
Frequency of changes to the schema
Business criticality of up-to-date data
For organizations with schemas that change often and where surfacing the latest data is business critical, daily may be appropriate. For those with schemas that do not change often and which are less critical, weekly or even monthly may make sense. Consult your data.world representative for more tailored recommendations on how best to optimize your catalog collector processes.