[pgpointcloud] PC_Get array of dimensions

[Lars]

Regina,

Thank you for the suggestion.

Using LATERAL makes the query easier to read but it does not appear to have any performance gain.

________________________________
Fra: Regina Obe <lr at pcorp.us>
Sendt: 8. mai 2018 14:45
Til: 'Lars'; pgpointcloud at lists.osgeo.org
Emne: RE: [pgpointcloud] PC_Get array of dimensions


Lars,



Have you tried using LATERAL for this.  This seems like an example just dying for that to be used.



For example



SELECT  PC_Get(pae, 'X') AS X, PC_Get(pae, 'Y') AS Y, PC_GET(pae, 'Z') As Z

FROM import , LATERAL PC_Explode(import.pa) AS pae

WHERE PC_Intersects(...);







From: pgpointcloud [mailto:pgpointcloud-bounces at lists.osgeo.org] On Behalf Of Lars
Sent: Tuesday, May 08, 2018 5:32 AM
To: pgpointcloud at lists.osgeo.org
Subject: [pgpointcloud] PC_Get array of dimensions



Hello,



Does pgpointcloud have any plans to add a generic PC_Get function that accepts an array of input names? There was a discussion on the subject a while back but cannot see any new function. http://lists.osgeo.org/pipermail/pdal/2014-November/000429.html



The suggested function would make the query more compact and easier to read. Could it also improve performance?



A simple query without PC_Get/PC_Explode takes 1 ms.

select id from import where PC_Intersects(...);



Updating the test to include X value and the time increases to 21 ms.

select PC_Get(PC_Explode(pa), 'X') from import where PC_Intersects(...);



Updating the test to include X and Y and it takes 34ms.

select PC_Get(PC_Explode(pa), 'X'), PC_Get(PC_Explode(pa), 'Y')  from import where PC_Intersects(...);



Updating the test to include X,Y and Z and it takes 46ms.

select PC_Get(PC_Explode(pa), 'X'), PC_Get(PC_Explode(pa), 'Y'), PC_Get(PC_Explode(pa), 'Z')  from import where PC_Intersects(...);



It appear that for each dimension added the time increase quiet a bit. This is obviously a very simple test but just wanted to get a feedback.



Using Windows 7, PostgresSQL 10.3 and PostGIS 2.4.4



kind regards, Lars
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