Creating a partition index in AWS Glue

Creating a partition index in AWS Glue can help speed up queries that rely on specific partition columns. This blog thread illustrates creating a partition index on an AWS Glue table.

Let's assume you have a table called sales_data in AWS Glue, which is partitioned by year, month, and day. If you frequently query the data by year and month, you can create a partition index on these columns to improve performance.

Example: Creating a Partition Index

1. Set up the Table and Partitions (if not already set): Ensure your table is set up in AWS Glue Data Catalog and is partitioned by year, month, and day.

   python
   import boto3
   
   glue = boto3.client('glue')
   
   response = glue.create_table(
       DatabaseName='my_database',
       TableInput={
           'Name': 'sales_data',
           'PartitionKeys': [
               {'Name': 'year', 'Type': 'int'},
               {'Name': 'month', 'Type': 'int'},
               {'Name': 'day', 'Type': 'int'}
           ],
           'StorageDescriptor': {
               'Columns': [
                   {'Name': 'product_id', 'Type': 'string'},
                   {'Name': 'quantity', 'Type': 'int'},
                   {'Name': 'price', 'Type': 'double'}
               ],
               'Location': 's3://my-bucket/sales_data/'
           }
       }
   )
   

2. Create a Partition Index: To create a partition index for the year and month columns, use the following example code:

   python
    
   response = glue.create_partition_index(
       DatabaseName='my_database',
       TableName='sales_data',
       PartitionIndex={
           'Keys': ['year', 'month'],  # Specify the columns to index
           'IndexName': 'year_month_index'  # Name the index
       }
   )
   
   print("Partition Index Created:", response)
   

3. Verifying the Partition Index: To check that the partition index was created successfully, you can use the get_partition_indexes method:

   python
    
   response = glue.get_partition_indexes(
       DatabaseName='my_database',
       TableName='sales_data'
   )
   
   print("Partition Indexes:", response['PartitionIndexList'])
   

Explanation of the Code

• DatabaseName and TableName specify the database and table in Glue Data Catalog.
• PartitionIndex includes:
  • Keys: A list of partition columns to index, in this case, ['year', 'month'].
  • IndexName: A unique name for the index, like year_month_index.

Creating this index will allow AWS Glue and any service querying the table, such as Athena, to quickly locate partitions based on year and month, improving performance on queries filtering by these columns.