Amazon Redshift will no longer support the creation of new Python UDFs starting November 1, 2025.
If you would like to use Python UDFs, create the UDFs prior to that date.
Existing Python UDFs will continue to function as normal. For more information, see the
blog post
Managing concurrent write operations
Some applications require not only concurrent querying and loading, but also the ability to write to multiple tables or the same table concurrently. In this context, concurrently means overlapping, not scheduled to run at precisely the same time. Two transactions are considered to be concurrent if the second one starts before the first commits. Concurrent operations can originate from different sessions that are controlled either by the same user or by different users.
Amazon Redshift supports these types of applications by allowing tables to be read while they are being incrementally loaded or modified. Queries simply see the latest committed version, or snapshot, of the data, rather than waiting for the next version to be committed. If you want a particular query to wait for a commit from another write operation, you have to schedule it accordingly.
Note
Amazon Redshift supports a default automatic commit behavior in which each separately run SQL command commits individually. If you enclose a set of commands in a transaction block (defined by BEGIN and END statements), the block commits as one transaction, so you can roll it back if necessary. Exceptions to this behavior are the TRUNCATE and VACUUM commands, which automatically commit all outstanding changes made in the current transaction.
Some SQL clients issue BEGIN and COMMIT commands automatically, so the client
controls whether a group of statements are run as a transaction or each individual
statement is run as its own transaction. Check the documentation for the interface
you are using. For example, when using the Amazon Redshift JDBC driver, a JDBC
PreparedStatement with a query string that contains multiple
(semicolon separated) SQL commands runs all the statements as a single transaction.
In contrast, if you use SQL Workbench/J and set AUTO COMMIT ON, then if you run
multiple statements, each statement runs as its own transaction.
The following topics describe some of the key concepts and use cases that involve transactions, database snapshots, updates, and concurrent behavior.
Topics
