Do we have a stream mode where the entire resultset is not loaded in memory?

[nvqua...@gmail.com]

Mysql2 gem has a streaming option when dealing with large resultset, so that the load on memory is reduced. https://github.com/brianmario/mysql2#streaming

Do we have such option or a way to solve it when dealing with query that returns a large amount of data?

Thanks!

Huy

[Lars Kanis]

You have two options with PostgreSQL: The single row mode or the COPY command:

For the single row mode use the example here: http://deveiate.org/code/pg/PG/Result.html#method-i-stream_each

For COPY you can use the copy_data method: http://deveiate.org/code/pg/PG/Connection.html#method-i-copy_data

This is most interesting, if you need the rows in CSV format. If you need to process the result set in ruby, you can use a CopyRow-decoder instead: http://deveiate.org/code/pg/PG/TextDecoder/CopyRow.html

COPY is typically a bit faster than the single row mode for data from the database. For data to the database COPY is typically way faster than any other method.

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Kind Regards,

Lars