Your query filters out more than half of the original data set.Use the following guidelines to determine if S3 Select is a good fit for your workload: For more information on S3 Select request cost, please see Amazon S3 Cloud Storage Pricing. We recommend that you benchmark your workloads with and without S3 Select to see if using it may be suitable for your workload. If the query doesn’t filter any data then pushdown may not add any additional value and the user will be charged for S3 Select requests. Filtering a large number of rows should result in better performance. The performance of S3SelectPushdown depends on the amount of data filtered by the query. S3SelectPushdown is disabled by default and you should enable it in production after proper benchmarking and cost analysis. Should I turn on S3 Select for my workload on Presto? With S3SelectPushdown Presto only retrieves the required data from S3 instead of entire S3 objects reducing both latency and network usage. S3SelectPushdown can be enabled on your hive catalog as a configuration to enable pushing down projection (SELECT) and predicate (WHERE) processing to S3 Select. For a more detailed understanding of the difference between Athena and Presto see here. As such the comparison between Athena and S3 select is the same as outlined above. What is the difference between S3 Select and Athena?Īthena is Amazon’s fully managed service for Presto. Varies by format and underlying connector Comparisonĭelimited, CSV, RCFile, JSON, SequenceFile, ORC, Avro, and Parquet
Presto on the other hand is a comprehensive ANSI SQL compliant query engine that can work with various data sources. S3 Select is a minimalistic version of pushdown to source with a limited support for the ANSI SQL Dialect. What is the difference between S3 Select and Presto?
You must use the data types specified in the object’s schema.The maximum uncompressed row group size is 256 MB.You must specify the output format as CSV or JSON. Amazon S3 Select doesn’t support Parquet output.Amazon S3 Select doesn’t support whole-object compression for Parquet objects.Amazon S3 Select supports only columnar compression using GZIP or Snappy.You cannot specify the S3 Glacier Flexible Retrieval, S3 Glacier Deep Archive, or REDUCED_REDUNDANCY storage classes.Īdditional limitations apply when using Amazon S3 Select with Parquet objects:.Amazon S3 Select can only emit nested data using the JSON output format.The maximum length of a record in the input or result is 1 MB.
The maximum length of a SQL expression is 256 KB.For more information about the SQL elements that are supported by Amazon S3 Select, see SQL reference for Amazon S3 Select and S3 Glacier Select.Īdditionally, the following limits apply when using Amazon S3 Select: What are the limitations of S3 Select?Īmazon S3 Select supports a subset of SQL. You can perform S3 Select SQL queries using AWS SDKs, the SELECT Object Content REST API, the AWS Command Line Interface (AWS CLI), or the Amazon S3 console. How can I use Amazon S3 Select standalone? The returned filtered results can be in CSV or JSON, and you can determine how the records in the result are delimited. The stored objects can be compressed with GZIP or BZIP2 (for CSV and JSON objects only). What formats are supported for S3 Select?Ĭurrently Amazon S3 Select only works on objects stored in CSV, JSON, or Apache Parquet format. This reduces the amount of data that Amazon S3 transfers, which reduces the cost, latency, and data processing time at the client. Instead of pulling the entire dataset and then manually extracting the data that you need, you can use S3 Select to filter this data at the source (i.e. Amazon S3 Select Limitations What is Amazon S3 Select?Īmazon S3 Select allows you to use simple structured query language (SQL) statements to filter the contents of an Amazon S3 object and retrieve just the subset of data that you need.
0 kommentar(er)
