Fixes for StationLink

.gitignore

@@ -10,6 +10,7 @@ data/TradeDangerous.db-journal
 data/TradeDangerous.prices
 market/
 *.orig
+*.prev
 
 wip/
 pycallgraph.png

buildcache.py

@@ -711,21 +711,24 @@ def generateStationLink(tdenv, db):
     tdenv.DEBUG0("Generating StationLink table")
     db.create_function("sqrt", 1, math.sqrt)
     db.execute("""
-        INSERT INTO StationLink
+            INSERT INTO StationLink
             SELECT  lhs.system_id AS lhs_system_id,
                     lhs.station_id AS lhs_station_id,
                     rhs.system_id AS rhs_system_id,
                     rhs.station_id AS rhs_station_id,
-                    ((lSys.pos_x - rSys.pos_x) * (lSys.pos_x - rSys.pos_x)) +
-                    ((lSys.pos_y - rSys.pos_y) * (lSys.pos_y - rSys.pos_y)) +
-                    ((lSys.pos_z - rSys.pos_z) * (lSys.pos_z - rSys.pos_z)) dist
-              FROM  System AS lSys
-                    INNER JOIN Station lhs
-                        ON (lSys.system_id = lhs.system_id),
-                    System AS rSys
-                    INNER JOIN Station rhs
-                        ON (rSys.system_id = rhs.system_id)
-             WHERE  lhs.system_id != rhs.system_id
+                    sqrt(
+                        ((lSys.pos_x - rSys.pos_x) * (lSys.pos_x - rSys.pos_x)) +
+                        ((lSys.pos_y - rSys.pos_y) * (lSys.pos_y - rSys.pos_y)) +
+                        ((lSys.pos_z - rSys.pos_z) * (lSys.pos_z - rSys.pos_z))
+                        )
+              FROM  Station AS lhs
+                    INNER JOIN System AS lSys
+                        ON (lhs.system_id = lSys.system_id),
+                    Station AS rhs
+                    INNER JOIN System AS rSys
+                        ON (rhs.system_id = rSys.system_id)
+              WHERE
+                    lhs.system_id != rhs.system_id
     """)
     db.commit()
 
@@ -754,6 +757,9 @@ def buildCache(tdenv, dbPath, sqlPath, pricesPath, importTables, defaultZero=Fal
     backupDBName = dbFilename  + ".prev"
     tempPath, backupPath = Path(tempDBName), Path(backupDBName)
 
+    if tempPath.exists():
+        tempPath.unlink()
+
     tempDB = sqlite3.connect(tempDBName)
     # Read the SQL script so we are ready to populate structure, etc.
     tdenv.DEBUG0("Executing SQL Script '{}' from '{}'", sqlPath, os.getcwd())
@@ -777,9 +783,10 @@ def buildCache(tdenv, dbPath, sqlPath, pricesPath, importTables, defaultZero=Fal
 
     tdenv.DEBUG0("Swapping out db files")
 
-    if backupPath.exists():
-        backupPath.unlink()
-    dbPath.rename(backupPath)
+    if dbPath.exists():
+        if backupPath.exists():
+            backupPath.unlink()
+        dbPath.rename(backupPath)
     tempPath.rename(dbPath)
 
     tdenv.DEBUG0("Finished")

data/TradeDangerous.sql

@@ -241,16 +241,16 @@ CREATE INDEX idx_buying_price ON StationBuying (item_id, price);
 
 CREATE TABLE StationLink
  (
-	lhs_system_id INTEGER NOT NULL,
-	lhs_station_id INTEGER NOT NULL,
-	rhs_system_id INTEGER NOT NULL CHECK (lhs_system_id != rhs_system_id),
-	rhs_station_id INTEGER NOT NULL CHECK (lhs_station_id != rhs_station_id),
-	dist DOUBLE NOT NULL CHECK (dist > 0.0),
-	PRIMARY KEY (lhs_station_id, rhs_station_id)
- )
+   lhs_system_id INTEGER NOT NULL,
+   lhs_station_id INTEGER NOT NULL,
+   rhs_system_id INTEGER NOT NULL,
+   rhs_station_id INTEGER NOT NULL,
+   dist DOUBLE NOT NULL CHECK (dist > 0.0),
+   PRIMARY KEY (lhs_station_id, rhs_station_id)
+ ) WITHOUT ROWID
 ;
-CREATE INDEX idx_stn_dist ON StationLink (lhs_station_id, rhs_station_id);
-CREATE INDEX idx_stn_sys ON StationLink (lhs_system_id, rhs_system_id);
+CREATE INDEX idx_stn_dist ON StationLink (lhs_station_id, dist, rhs_station_id);
+CREATE INDEX idx_stn_sys ON StationLink (lhs_system_id, rhs_system_id, dist);
 
 CREATE VIEW vPrice AS
 	SELECT	si.station_id AS station_id,