![]() The list of Redshift SQL commands differs from the list of PostgreSQL commands, and even when both platforms implement the same command, their syntax is often different. While a lot of the two platforms' SQL syntax is the same, there are plenty of differences as well. Differences in SQLīoth databases use SQL as their native language. It's more like the difference between dialects – the American and British versions of English, for example. But the good news is that if you're familiar with PostgreSQL commands and concepts, learning Redshift isn't like learning a foreign language. PostgreSQL can serve as a data warehouse for smaller volumes of data, but it can't match the performance of Redshift's column-oriented architecture. The architectural changes Amazon made to Redshift make it better able to handle large volumes of data for analytical queries. Redshift doesn't enforce primary key, foreign key, or uniqueness constraints, though Amazon says "primary keys and foreign keys are used as planning hints and they should be declared if your ETL process or some other process in your application enforces their integrity.".When you insert, update, or copy data in a Redshift table, new rows get added to an unsorted region, and are sorted only when the table is vacuumed or deep copied. Instead, each table has a sort key, which determines how rows are ordered when the data is loaded. If you distribute a pair of tables on the joining keys, the leader node collocates the rows on the slices according to the values in the joining columns so that matching values from the common columns are physically stored together." PostgreSQL lacks distribution styles and distribution keys. Redshift's documentation says, "The leader node will attempt to place matching values on the same node slice. One of the distribution styles is key distribution, in which the rows are distributed according to the values in a specified column. When you load data into a Redshift table, Redshift distributes the rows of the table across nodes according to the table's distribution style.In PostgreSQL a single database connection cannot utilize more than one CPU, while Redshift is architected for parallel processing across multiple nodes.Redshift is a columnar database better suited for analytics, and thus a more appropriate platform for a data warehouse. Under the hood, PostgreSQL is a traditional row-oriented relational database, great for processing transactional data.If you're familiar with PostgreSQL features and syntax, how easy will it be to get used to Redshift?įirst, there are architectural differences between Redshift and PostgreSQL: PADB was itself based on PostgreSQL – so to some extent, Redshift is based on PostgreSQL – but "based on" leaves a lot of room for difference. ![]() In 2015 Amazon CTO Werner Vogels called Redshift "the fastest-growing service in AWS, ever." Meanwhile, ParAccel was acquired by Actian in 2013, and PADB was renamed Actian Matrix. While that deal might have seemed worthwhile for ParAccel at the time, it worked out even better for Amazon in the long run. PADB was notable because it was a columnar database that ran on commodity hardware, which made it a natural choice as a basis for a cloud-based analytic database platform. Amazon invested $20 million in a company called ParAccel, and in return gained the license to use code from ParAccel Analytic Database (PADB) for Redshift. Amazon Redshift debuted in 2012 as the first cloud data warehouse, and remains the most popular one today. ![]()
0 Comments
Leave a Reply. |
AuthorWrite something about yourself. No need to be fancy, just an overview. ArchivesCategories |