Why does S3 Select have SQL length limit to 256 KB?

Greetings,

The maximum length of a SQL expression in Amazon S3 Select is 256 KB. This limit is in place to ensure that the service can handle queries efficiently and without experiencing performance degradation. When a query is submitted to S3 Select, the query expression is processed on a distributed infrastructure and it's important to limit the size of the query in order to avoid any processing issues.

It is not possible to configure S3 Select to allow SQL expressions larger than 256 KB. If you require a larger query expression, you may need to break it up into smaller expressions and execute them separately. Alternatively, you may want to consider using other AWS services, such as Amazon Athena or Amazon Redshift, which have higher query limits and can handle larger datasets.

It's also worth noting that while the maximum length of a SQL expression is limited to 256 KB, the size of the input data can be much larger. S3 Select can process objects up to 400 MB in size and can handle compressed files in a variety of formats, including GZIP and BZIP2. If you're working with larger datasets, S3 Select can still be a very powerful tool for extracting the data you need.

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