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Thread: what is sublinks in query planner?

what is sublinks in query planner?

From
Sandeep Gupta
Date:
Hi,

 
 I looked for description of sublinks in the code as well as online but failed to come with any information. Was wondering someone can provide a line or two of what sublinks are suppose to do?

Thanks.
Sandeep

Re: what is sublinks in query planner?

From
Tom Lane
Date:
Sandeep Gupta <gupta.sandeep@gmail.com> writes:
>  I looked for description of sublinks in the code as well as online but
> failed to come with any information. Was wondering someone can provide a
> line or two of what sublinks are suppose to do?

They're sub-SELECTs used in expression contexts (ie, not directly in a
FROM list).  The comments for the SubLink and SubPlan node types in
primnodes.h may help you.

            regards, tom lane

Re: what is sublinks in query planner?

From
Sandeep Gupta
Date:
Hi Tom,

 Sure. Thanks for the info. This helps. I will look into primnodes.h as well.

-Sandeep






On Fri, Mar 28, 2014 at 3:56 PM, Tom Lane <tgl@sss.pgh.pa.us> wrote:
Sandeep Gupta <gupta.sandeep@gmail.com> writes:
>  I looked for description of sublinks in the code as well as online but
> failed to come with any information. Was wondering someone can provide a
> line or two of what sublinks are suppose to do?

They're sub-SELECTs used in expression contexts (ie, not directly in a
FROM list).  The comments for the SubLink and SubPlan node types in
primnodes.h may help you.

                        regards, tom lane