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  1. Preface
  2. Introduction to Microsoft Azure Synapse SQL Connector
  3. Connections for Microsoft Azure Synapse SQL
  4. Mappings for Microsoft Azure Synapse SQL
  5. Upgrading to Microsoft Azure Synapse SQL Connector
  6. Migrating a mapping
  7. SQL ELT optimization
  8. Data type reference
  9. Troubleshooting

Microsoft Azure Synapse SQL Connector

Microsoft Azure Synapse SQL Connector

Key range partitioning

Key range partitioning

You can configure key range partitioning when you use a
mapping
task to read data from
Microsoft Azure Synapse SQL
sources. With key range partitioning, the Secure Agent distributes rows of source data based on the fields that you define as partition keys. The Secure Agent compares the field value to the range values for each partition and sends rows to the appropriate partitions.
Use key range partitioning for columns that have an even distribution of data values. Otherwise, the partitions might have unequal size. For example, a column might have 10 rows between key values 1 and 1000 and the column might have 999 rows between key values 1001 and 2000. If the mapping includes multiple sources, use the same number of key ranges for each source.
When you define key range partitioning for a column, the Secure Agent reads the rows that are within the specified partition range. For example, if you configure two partitions for a column with the ranges as 10 through 20 and 30 through 40, the Secure Agent does not read the rows 20 through 30 because these rows are not within the specified partition range.
You can configure a partition key for fields of the following data types:
  • Any type of number data type. However, you cannot use decimals in key range values.
You cannot use key range partitions when you create a mapping in advanced mode and when a mapping includes any of the following transformations:
  • Web Services
  • XML to Relational
When you use multiple partitions, the start range for the first partition and the end range for the last partition are not included in the WHERE clause of the polybase command.
Custom queries and SQL override are not applicable when you use key range partitioning.

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