dougal-software/etc/db/upgrades/upgrade19-v0.3.6-optimise-geometry-functions.sql

-- Fix not being able to edit a time-based event.
--
-- New schema version: 0.3.6
--
-- ATTENTION:
--
-- ENSURE YOU HAVE BACKED UP THE DATABASE BEFORE RUNNING THIS SCRIPT.
--
--
-- NOTE: This upgrade affects all schemas in the database.
-- NOTE: Each application starts a transaction, which must be committed
-- or rolled back.
--
-- This optimises geometry_from_tstamp() by many orders of magnitude
-- (issue #241). The redefinition of geometry_from_tstamp() necessitates
-- redefining dependent functions.
--
-- We also drop the index on real_time_inputs.meta->'tstamp' as it is no
-- longer used.
--
-- To apply, run as the dougal user:
--
-- psql <<EOF
-- \i $THIS_FILE
-- COMMIT;
-- EOF
--
-- NOTE: It can be applied multiple times without ill effect.
--

BEGIN;

CREATE OR REPLACE PROCEDURE show_notice (notice text) AS $$
BEGIN
	RAISE NOTICE '%', notice;
END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE PROCEDURE pg_temp.upgrade_survey_schema (schema_name text) AS $$
BEGIN

	RAISE NOTICE 'Updating schema %', schema_name;
	-- We need to set the search path because some of the trigger
	-- functions reference other tables in survey schemas assuming
	-- they are in the search path.
	EXECUTE format('SET search_path TO %I,public', schema_name);

	CREATE OR REPLACE PROCEDURE augment_event_data ()
	LANGUAGE sql
	AS $inner$
		-- Populate the timestamp of sequence / point events
		UPDATE event_log_full
		SET tstamp = tstamp_from_sequence_shot(sequence, point)
		WHERE
			tstamp IS NULL AND sequence IS NOT NULL AND point IS NOT NULL;

		-- Populate the geometry of sequence / point events for which
		-- there is raw_shots data.
		UPDATE event_log_full
		SET meta = meta ||
			jsonb_build_object(
				'geometry',
				(
					SELECT st_transform(geometry, 4326)::jsonb
					FROM raw_shots rs
					WHERE rs.sequence = event_log_full.sequence AND rs.point = event_log_full.point
				)
			)
		WHERE
			sequence IS NOT NULL AND point IS NOT NULL AND
			NOT meta ? 'geometry';

		-- Populate the geometry of time-based events
		UPDATE event_log_full e
		SET
			meta = meta || jsonb_build_object('geometry',
				(SELECT st_transform(g.geometry, 4326)::jsonb
				FROM geometry_from_tstamp(e.tstamp, 3) g))
		WHERE
			tstamp IS NOT NULL AND
			sequence IS NULL AND point IS NULL AND
			NOT meta ? 'geometry';

		-- Get rid of null geometries
		UPDATE event_log_full
		SET
			meta = meta - 'geometry'
		WHERE
			jsonb_typeof(meta->'geometry') = 'null';

		-- Simplify the GeoJSON when the CRS is EPSG:4326
		UPDATE event_log_full
		SET
			meta = meta #- '{geometry, crs}'
		WHERE
			meta->'geometry'->'crs'->'properties'->>'name' = 'EPSG:4326';

	$inner$;

	COMMENT ON PROCEDURE augment_event_data()
		IS 'Populate missing timestamps and geometries in event_log_full';

END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE PROCEDURE pg_temp.upgrade () AS $outer$
DECLARE
	row RECORD;
BEGIN

	CALL show_notice('Dropping index from real_time_inputs.meta->tstamp');
	DROP INDEX IF EXISTS meta_tstamp_idx;

	CALL show_notice('Creating function geometry_from_tstamp');
	CREATE OR REPLACE FUNCTION public.geometry_from_tstamp(
		IN ts timestamptz,
		IN tolerance numeric,
		OUT "geometry" geometry,
		OUT "delta" numeric)
	AS $inner$
		SELECT
			geometry,
			extract('epoch' FROM tstamp - ts ) AS delta
		FROM real_time_inputs
		WHERE
			geometry IS NOT NULL AND
			tstamp BETWEEN (ts - tolerance * interval '1 second') AND (ts + tolerance * interval '1 second')
		ORDER BY abs(extract('epoch' FROM tstamp - ts ))
		LIMIT 1;
	$inner$ LANGUAGE SQL;

	COMMENT ON FUNCTION public.geometry_from_tstamp(timestamptz, numeric)
		IS 'Get geometry from timestamp';

	FOR row IN
		SELECT schema_name FROM information_schema.schemata
		WHERE schema_name LIKE 'survey_%'
		ORDER BY schema_name
	LOOP
		CALL pg_temp.upgrade_survey_schema(row.schema_name);
	END LOOP;
END;
$outer$ LANGUAGE plpgsql;

CALL pg_temp.upgrade();

CALL show_notice('Cleaning up');
DROP PROCEDURE pg_temp.upgrade_survey_schema (schema_name text);
DROP PROCEDURE pg_temp.upgrade ();

CALL show_notice('Updating db_schema version');
INSERT INTO public.info VALUES ('version', '{"db_schema": "0.3.6"}')
ON CONFLICT (key) DO UPDATE
	SET value = public.info.value || '{"db_schema": "0.3.6"}' WHERE public.info.key = 'version';


CALL show_notice('All done. You may now run "COMMIT;" to persist the changes');
DROP PROCEDURE show_notice (notice text);

--
--NOTE Run `COMMIT;` now if all went well
--