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When I unload a table from amazon redshift to S3, it always splits the table into two parts no matter how small the table. I have read the redshift documentation regarding unloading, but no answers other than it says sometimes it splits the table (I've never seen it not do that). I have two questions:
Has anybody every seen a case where only one file is created?
Is there a way to force redshift to unload into a single file?
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The following steps to easily perform Snowflake Unload to S3 are listed below: Step 1: Allowing the Virtual Private Cloud IDs. Step 2: Configuring an Amazon S3 Bucket. Step 3: Unloading Data into an External Stage.
Unload VENUE to a CSV file The following example unloads the VENUE table and writes the data in CSV format to s3://mybucket/unload/ . unload ('select * from venue') to 's3://mybucket/unload/' iam_role 'arn:aws:iam::0123456789012:role/MyRedshiftRole' CSV; Suppose that the VENUE table contains the following rows.
To unload data from database tables to a set of files in an Amazon S3 bucket, you can use the UNLOAD command with a SELECT statement. You can unload text data in either delimited format or fixed-width format, regardless of the data format that was used to load it.
Let's say that we intend to export this data into an AWS S3 bucket. The primary method natively supports by AWS Redshift is the “Unload” command to export data.
Amazon recently added support for unloading to a single file by using PARALLEL OFF in the UNLOAD statement. Note that you still can end up with more than one file if it is bigger than 6.2GB.
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As of May 6, 2014 UNLOAD queries support a new PARALLEL options. Passing PARALLEL OFF will output a single file if your data is less than 6.2 gigs (data is split into 6.2 GB chunks).
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