fix(bq|random): ST_GENERATEPOINTS returning exact name of points

[vdelacruzb]

Description

Shortcut

• Story: https://app.shortcut.com/cartoteam/story/379986/internal-st-generate-points-generating-generate-array-error-or-oddly-low-number-of-points-generated

• Autolink: [sc-379986]

• Check possible optimizations of ST GENERATEPOINTS [sc-386473]

This ticket makes ST_GENERATEPOINTS return the exact number of points requested. As mentioned in the doc there was the small chance of returning less points but in some cases the points returned are way less than expected. I've gone for an approach equal to the one already implemented in Snowflake.

I saw that in Snowflake it worked much faster than the previous approach but it has to be with keeping the result as ARRAY(STRING) in this case it was the same. But UNNESTING + parsing to GEOG + ARRAY_AGG make this approach slower than the original approach. So going for this approach or not depends on what we want to prioritize.

I removed the warning in the 3 docs because in other providers we return the exact name of points.

Type of change

• Fix

Acceptance

with a as (SELECT `carto-un`.carto.ST_GENERATEPOINTS(ST_GEOGFROM('{"type":"Polygon","coordinates":[[[-81.83228458193764,41.64497651445618],[-73.83438791064249,45.21751495507643],[-70.9321626546763,45.07761121864185],[-68.39615548876748,47.7299818321738],[-63.739164722242194,41.38848032241172],[-32.653971565046206,56.517498752322986],[-56.58596382377746,60.899302859749085],[-73.81312713859674,77.06548201227298],[-150.572477438432,77.03299512273315],[-140.85567102668878,70.45234214268247],[-140.15529260872003,48.81513877082211],[-93.76095161674623,49.282176839280744],[-83.29647407768371,46.472790002158526],[-81.83228458193764,41.64497651445618]]]}'), 500000) e
)
select ARRAY_LENGTH(e) from a;
-- time 5 sec, 344354 points

with a as (SELECT `cartodb-data-engineering-team`.vdelacruz_carto.ST_GENERATEPOINTS(ST_GEOGFROM('{"type":"Polygon","coordinates":[[[-81.83228458193764,41.64497651445618],[-73.83438791064249,45.21751495507643],[-70.9321626546763,45.07761121864185],[-68.39615548876748,47.7299818321738],[-63.739164722242194,41.38848032241172],[-32.653971565046206,56.517498752322986],[-56.58596382377746,60.899302859749085],[-73.81312713859674,77.06548201227298],[-150.572477438432,77.03299512273315],[-140.85567102668878,70.45234214268247],[-140.15529260872003,48.81513877082211],[-93.76095161674623,49.282176839280744],[-83.29647407768371,46.472790002158526],[-81.83228458193764,41.64497651445618]]]}'), 500000) e
)
select ARRAY_LENGTH(e) from a;
-- time 29 sec, 500000 points

[shortcut-integration]

This pull request has been linked to Shortcut Story #379986: [internal] ST Generate Points generating GENERATE_ARRAY error or oddly low number of points generated.

[shortcut-integration]

This pull request has been linked to Shortcut Story #386473: Check possible optimizations of ST_GENERATEPOINTS Function [BigQuery, Redshift].