further split up the big geometry index

Adds partial indexes for all geometry queries used during import.
A full index is not necessary anymore at that point. Still create
the index afterwards for use in queries.

Also adds documentation for all indexes on where they are used.

lib-sql/functions/interpolation.sql

@@ -52,7 +52,9 @@ BEGIN
 
   IF parent_place_id is null THEN
     FOR location IN SELECT place_id FROM placex
-        WHERE ST_DWithin(geom, placex.geometry, 0.001) and placex.rank_search = 26
+        WHERE ST_DWithin(geom, placex.geometry, 0.001)
+              and placex.rank_search = 26
+              and placex.osm_type = 'W' -- needed for index selection
         ORDER BY CASE WHEN ST_GeometryType(geom) = 'ST_Line' THEN
                   (ST_distance(placex.geometry, ST_LineInterpolatePoint(geom,0))+
                   ST_distance(placex.geometry, ST_LineInterpolatePoint(geom,0.5))+

lib-sql/functions/placex_triggers.sql

@@ -197,6 +197,7 @@ BEGIN
         SELECT place_id FROM placex
          WHERE bbox && geometry AND _ST_Covers(geometry, ST_Centroid(bbox))
                AND rank_address between 5 and 25
+               AND ST_GeometryType(geometry) in ('ST_Polygon','ST_MultiPolygon')
          ORDER BY rank_address desc
       LOOP
         RETURN location.place_id;
@@ -212,6 +213,7 @@ BEGIN
         SELECT place_id FROM placex
          WHERE bbox && geometry AND _ST_Covers(geometry, ST_Centroid(bbox))
                AND rank_address between 5 and 25
+               AND ST_GeometryType(geometry) in ('ST_Polygon','ST_MultiPolygon')
         ORDER BY rank_address desc
       LOOP
         RETURN location.place_id;
@@ -275,7 +277,9 @@ BEGIN
 
   -- If extratags has a place tag, look for linked nodes by their place type.
   -- Area and node still have to have the same name.
-  IF bnd.extratags ? 'place' and bnd_name is not null THEN
+  IF bnd.extratags ? 'place' and bnd.extratags->'place' != 'postcode'
+     and bnd_name is not null
+  THEN
     FOR linked_placex IN
       SELECT * FROM placex
       WHERE (position(lower(name->'name') in bnd_name) > 0
@@ -284,7 +288,6 @@ BEGIN
         AND placex.osm_type = 'N'
         AND (placex.linked_place_id is null or placex.linked_place_id = bnd.place_id)
         AND placex.rank_search < 26 -- needed to select the right index
-        AND placex.type != 'postcode'
         AND ST_Covers(bnd.geometry, placex.geometry)
     LOOP
       {% if debug %}RAISE WARNING 'Found type-matching place node %', linked_placex.osm_id;{% endif %}

lib-sql/indices.sql

@@ -5,13 +5,6 @@
 -- Copyright (C) 2022 by the Nominatim developer community.
 -- For a full list of authors see the git log.
 
--- The following indicies are only useful during imoprt when all of placex is processed.
-
-{% if drop %}
-  DROP INDEX IF EXISTS idx_placex_rank_address_sector;
-  DROP INDEX IF EXISTS idx_placex_rank_boundaries_sector;
-{% endif %}
-
 -- Indices used only during search and update.
 -- These indices are created only after the indexing process is done.
 
@@ -28,6 +21,9 @@ CREATE INDEX IF NOT EXISTS idx_placex_parent_place_id
   ON placex USING BTREE (parent_place_id) {{db.tablespace.search_index}}
   WHERE parent_place_id IS NOT NULL;
 ---
+CREATE INDEX IF NOT EXISTS idx_placex_geometry ON placex
+  USING GIST (geometry) {{db.tablespace.search_index}};
+---
 CREATE INDEX IF NOT EXISTS idx_placex_geometry_reverse_lookupPolygon
   ON placex USING gist (geometry) {{db.tablespace.search_index}}
   WHERE St_GeometryType(geometry) in ('ST_Polygon', 'ST_MultiPolygon')
@@ -43,9 +39,17 @@ CREATE INDEX IF NOT EXISTS idx_osmline_parent_osm_id
 ---
 CREATE INDEX IF NOT EXISTS idx_postcode_postcode
   ON location_postcode USING BTREE (postcode) {{db.tablespace.search_index}};
--- Indices only needed for updating.
 
-{% if not drop %}
+{% if drop %}
+---
+  DROP INDEX IF EXISTS idx_placex_geometry_address_area_candidates;
+  DROP INDEX IF EXISTS idx_placex_geometry_buildings;
+  DROP INDEX IF EXISTS idx_placex_geometry_lower_rank_ways;
+  DROP INDEX IF EXISTS idx_placex_wikidata;
+  DROP INDEX IF EXISTS idx_placex_rank_address_sector;
+  DROP INDEX IF EXISTS idx_placex_rank_boundaries_sector;
+{% else %}
+-- Indices only needed for updating.
 ---
   CREATE INDEX IF NOT EXISTS idx_location_area_country_place_id
     ON location_area_country USING BTREE (place_id) {{db.tablespace.address_index}};

lib-sql/tables.sql

@@ -137,7 +137,9 @@ CREATE TABLE place_addressline (
   ) {{db.tablespace.search_data}};
 CREATE INDEX idx_place_addressline_place_id on place_addressline USING BTREE (place_id) {{db.tablespace.search_index}};
 
-drop table if exists placex;
+---------  PLACEX - storage for all indexed places -----------------
+
+DROP TABLE IF EXISTS placex;
 CREATE TABLE placex (
   place_id BIGINT NOT NULL,
   parent_place_id BIGINT,
@@ -157,25 +159,54 @@ CREATE TABLE placex (
   postcode TEXT,
   centroid GEOMETRY(Geometry, 4326)
   ) {{db.tablespace.search_data}};
+
 CREATE UNIQUE INDEX idx_place_id ON placex USING BTREE (place_id) {{db.tablespace.search_index}};
-CREATE INDEX idx_placex_node_osmid ON placex USING BTREE (osm_id) {{db.tablespace.search_index}} WHERE osm_type = 'N';
+{% for osm_type in ('N', 'W', 'R') %}
-CREATE INDEX idx_placex_way_osmid ON placex USING BTREE (osm_id) {{db.tablespace.search_index}} WHERE osm_type = 'W';
+CREATE INDEX idx_placex_osmid_{{osm_type | lower}} ON placex
-CREATE INDEX idx_placex_relation_osmid ON placex USING BTREE (osm_id) {{db.tablespace.search_index}} WHERE osm_type = 'R';
+  USING BTREE (osm_id) {{db.tablespace.search_index}}
-CREATE INDEX idx_placex_linked_place_id ON placex USING BTREE (linked_place_id) {{db.tablespace.address_index}} WHERE linked_place_id IS NOT NULL;
+  WHERE osm_type = '{{osm_type}}';
-CREATE INDEX idx_placex_geometry ON placex USING GIST (geometry) {{db.tablespace.search_index}};
+{% endfor %}
+
+-- Usage: - removing linkage status on update
+--        - lookup linked places for /details
+CREATE INDEX idx_placex_linked_place_id ON placex
+  USING BTREE (linked_place_id) {{db.tablespace.address_index}}
+  WHERE linked_place_id IS NOT NULL;
+
+-- Usage: - check that admin boundaries do not overtake each other rank-wise
+--        - check that place node in a admin boundary with the same address level
+--        - boundary is not completely contained in a place area
+--        - parenting of large-area or unparentable features
 CREATE INDEX idx_placex_geometry_address_area_candidates ON placex
   USING gist (geometry) {{db.tablespace.address_index}}
   WHERE rank_address between 1 and 25
         and ST_GeometryType(geometry) in ('ST_Polygon','ST_MultiPolygon');
+
+-- Usage: - POI is within building with housenumber
 CREATE INDEX idx_placex_geometry_buildings ON placex
   USING {{postgres.spgist_geom}} (geometry) {{db.tablespace.address_index}}
   WHERE address is not null and rank_search = 30
         and ST_GeometryType(geometry) in ('ST_Polygon','ST_MultiPolygon');
+
+-- Usage: - linking of similar named places to boundaries
+--        - linking of place nodes with same type to boundaries
+--        - lookupPolygon()
 CREATE INDEX idx_placex_geometry_placenode ON placex
   USING {{postgres.spgist_geom}} (geometry) {{db.tablespace.address_index}}
   WHERE osm_type = 'N' and rank_search < 26
-        and class = 'place' and type != 'postcode' and linked_place_id is null;
+        and class = 'place' and type != 'postcode';
-CREATE INDEX idx_placex_wikidata on placex USING BTREE ((extratags -> 'wikidata')) {{db.tablespace.address_index}} WHERE extratags ? 'wikidata' and class = 'place' and osm_type = 'N' and rank_search < 26;
+
+-- Usage: - is node part of a way?
+--        - find parent of interpolation spatially
+CREATE INDEX idx_placex_geometry_lower_rank_ways ON placex
+  USING {{postgres.spgist_geom}} (geometry) {{db.tablespace.address_index}}
+  WHERE osm_type = 'W' and rank_search >= 26;
+
+-- Usage: - linking place nodes by wikidata tag to boundaries
+CREATE INDEX idx_placex_wikidata on placex
+  USING BTREE ((extratags -> 'wikidata')) {{db.tablespace.address_index}}
+  WHERE extratags ? 'wikidata' and class = 'place'
+        and osm_type = 'N' and rank_search < 26;
 
 -- The following two indexes function as a todo list for indexing.