Redshift and error "opening multiple cursors..."

Discussion of open issues, suggestions and bugs regarding UniDAC (Universal Data Access Components) for Delphi, C++Builder, Lazarus (and FPC)
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mariot
Posts: 17
Joined: Mon 02 Feb 2015 11:35

Redshift and error "opening multiple cursors..."

Post by mariot » Thu 23 May 2019 10:46

Hi.

I use Unidac 7.3.10 and have problem with data access provider for Amazon Redshift.
When I open new query, while exist another open query (main), then this error appeared (after second record in main query is processed):
"opening multiple cursors from within the same client connection is not allowed"

I use provider for Amazon Redshift similar way as data access provider for PostgreSQL with similar program code. In PostgreSQL it is OK, in Amazon Redshift not.

With ODBC connection it is OK (for Amazon Redshift).

Any suggestion please?

mariot
Posts: 17
Joined: Mon 02 Feb 2015 11:35

Re: Redshift and error "opening multiple cursors..."

Post by mariot » Thu 23 May 2019 20:23

Solution: I had UniDirectional parameter set to true. When I set it to false, then using of Redshift provider is OK, but it is more slow.

MaximG
Devart Team
Posts: 1469
Joined: Mon 06 Jul 2015 11:34

Re: Redshift and error "opening multiple cursors..."

Post by MaximG » Fri 24 May 2019 13:39

The described issue is not caused by our driver functionality - it stems from the limitations that Amazon Redshift imposes on the use of cursors. Please see this page for a detailed description: https://docs.aws.amazon.com/en_us/redsh ... clare.html

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