Add columnsize = 0 option to FTS index

Since we don't use ranking functions and I don't see them being useful,
there is no point in having columnsize, which just takes extra space in
the database.

In my database of approximately 3.5 million events, disabling columnsize
saves about 62 MB.

The migration unfortunately has to rebuild the entire index to disable
it.

1 files changed, 22 insertions, 3 deletions

diff --git a/database.h b/database.h
index d44bb15..83be73c 100644
--- a/database.h
+++ b/database.h
@@ -31,7 +31,7 @@
 
 #define DATABASE_PATH "litterbox/litterbox.sqlite"
 
-enum { DatabaseVersion = 0 };
+enum { DatabaseVersion = 1 };
 
 #define ENUM_TYPE \
 	X(Privmsg, "privmsg") \
@@ -285,7 +285,8 @@ static const char *InitSQL = SQL(
 		network, channel, query, nick, user, target, message,
 		content = text,
 		content_rowid = event,
-		tokenize = 'porter'
+		tokenize = 'porter',
+		columnsize = 0
 	);
 
 	CREATE TRIGGER eventsInsert AFTER INSERT ON events BEGIN
@@ -300,6 +301,8 @@ static const char *InitSQL = SQL(
 		) SELECT 'delete', * FROM text WHERE event = old.event;
 	END;
 
+	PRAGMA user_version = 1;
+
 	COMMIT TRANSACTION;
 );
 
@@ -308,7 +311,23 @@ static inline void dbInit(void) {
 }
 
 static const char *MigrationSQL[] = {
-	NULL,
+	// Added columnsize = 0 option.
+	SQL(
+		BEGIN TRANSACTION;
+		DROP TABLE search;
+		CREATE VIRTUAL TABLE search USING fts5 (
+			network, channel, query, nick, user, target, message,
+			content = text,
+			content_rowid = event,
+			tokenize = 'porter',
+			columnsize = 0
+		);
+		INSERT INTO search (
+			rowid, network, channel, query, nick, user, target, message
+		) SELECT * FROM text;
+		PRAGMA user_version = 1;
+		COMMIT TRANSACTION;
+	),
 };
 
 static inline void dbMigrate(void) {