Fixed lots of unclosed ResultSets in Database and DatabaseUpdates.

src/main/kotlin/de/fabianonline/telegram_backup/Database.kt

@@ -56,7 +56,9 @@ class Database private constructor(var client: TelegramClient) {
 		try {
 			val rs = stmt!!.executeQuery("SELECT MAX(message_id) FROM messages WHERE source_type IN ('group', 'dialog')")
 			rs.next()
-			return rs.getInt(1)
+			val result = rs.getInt(1)
+			rs.close()
+			return result
 		} catch (e: SQLException) {
 			return 0
 		}
@@ -87,6 +89,7 @@ class Database private constructor(var client: TelegramClient) {
 						missing.add(i)
 					}
 				}
+				rs.close()
 				return missing
 			} catch (e: SQLException) {
 				e.printStackTrace()
@@ -111,16 +114,7 @@ class Database private constructor(var client: TelegramClient) {
 
 	}
 
-	fun getMessagesFromUserCount(): Int {
+	fun getMessagesFromUserCount() = queryInt("SELECT COUNT(*) FROM messages WHERE sender_id=" + user_manager.user!!.getId())
-		try {
-			val rs = stmt!!.executeQuery("SELECT COUNT(*) FROM messages WHERE sender_id=" + user_manager.user!!.getId())
-			rs.next()
-			return rs.getInt(1)
-		} catch (e: SQLException) {
-			throw RuntimeException(e)
-		}
-
-	}
 
 	fun getMessageTypesWithCount(): HashMap<String, Int> = getMessageTypesWithCount(GlobalChat())
 
@@ -164,7 +158,9 @@ class Database private constructor(var client: TelegramClient) {
 		try {
 			val rs = stmt!!.executeQuery("PRAGMA encoding")
 			rs.next()
-			return rs.getString(1)
+			val result = rs.getString(1)
+			rs.close()
+			return result
 		} catch (e: SQLException) {
 			logger.debug("SQLException: {}", e)
 			return "unknown"
@@ -255,9 +251,7 @@ class Database private constructor(var client: TelegramClient) {
 
 	}
 
-	fun getTopMessageIDForChannel(id: Int): Int {
+	fun getTopMessageIDForChannel(id: Int): Int = queryInt("SELECT MAX(message_id) FROM messages WHERE source_id=$id AND source_type IN('channel', 'supergroup')")
-		return queryInt("SELECT MAX(message_id) FROM messages WHERE source_id=$id AND source_type IN('channel', 'supergroup')")
-	}
 
 	fun logRun(start_id: Int, end_id: Int, count: Int) {
 		try {
@@ -269,6 +263,7 @@ class Database private constructor(var client: TelegramClient) {
 			ps.setInt(2, end_id)
 			ps.setInt(3, count)
 			ps.execute()
+			ps.close()
 		} catch (e: SQLException) {
 		}
 
@@ -278,7 +273,9 @@ class Database private constructor(var client: TelegramClient) {
 		try {
 			val rs = stmt!!.executeQuery(query)
 			rs.next()
-			return rs.getInt(1)
+			val result = rs.getInt(1)
+			rs.close()
+			return result
 		} catch (e: SQLException) {
 			throw RuntimeException("Could not get count of messages.")
 		}
@@ -431,6 +428,9 @@ class Database private constructor(var client: TelegramClient) {
 			ps_insert_or_ignore.clearBatch()
 			conn!!.commit()
 			conn!!.setAutoCommit(true)
+			
+			ps.close()
+			ps_insert_or_ignore.close()
 		} catch (e: Exception) {
 			e.printStackTrace()
 			throw RuntimeException("Exception shown above happened.")
@@ -486,6 +486,9 @@ class Database private constructor(var client: TelegramClient) {
 			ps_insert_or_replace.clearBatch()
 			conn!!.commit()
 			conn!!.setAutoCommit(true)
+			
+			ps_insert_or_ignore.close()
+			ps_insert_or_replace.close()
 		} catch (e: Exception) {
 			e.printStackTrace()
 			throw RuntimeException("Exception shown above happened.")
@@ -535,6 +538,9 @@ class Database private constructor(var client: TelegramClient) {
 			ps_insert_or_replace.clearBatch()
 			conn!!.commit()
 			conn!!.setAutoCommit(true)
+			
+			ps_insert_or_ignore.close()
+			ps_insert_or_replace.close()
 		} catch (e: Exception) {
 			e.printStackTrace()
 			throw RuntimeException("Exception shown above happened.")
@@ -564,6 +570,7 @@ class Database private constructor(var client: TelegramClient) {
 			while (rs.next()) {
 				map.put("count.messages.type." + rs.getString(1), rs.getInt(2))
 			}
+			rs.close()
 			return map
 		} catch (e: Exception) {
 			throw RuntimeException(e)
@@ -586,6 +593,7 @@ class Database private constructor(var client: TelegramClient) {
 				map.put("count.messages.media_type.$s", rs.getInt(2))
 			}
 			map.put("count.messages.media_type.any", count)
+			rs.close()
 			return map
 		} catch (e: Exception) {
 			throw RuntimeException(e)
@@ -625,6 +633,7 @@ class Database private constructor(var client: TelegramClient) {
 			}
 			map.put("authors.count.others", count_others)
 			map.put("authors.all", all_data)
+			rs.close()
 			return map
 		} catch (e: Exception) {
 			throw RuntimeException(e)
@@ -634,7 +643,9 @@ class Database private constructor(var client: TelegramClient) {
 	fun getMessageCountForExport(c: AbstractChat): Int {
 		val rs = stmt!!.executeQuery("SELECT COUNT(*) FROM messages WHERE " + c.query);
 		rs.next()
-		return rs.getInt(1)
+		val result = rs.getInt(1)
+		rs.close()
+		return result
 	}
 
 	fun getMessageTimesMatrix(c: AbstractChat): Array<IntArray> {
@@ -647,6 +658,7 @@ class Database private constructor(var client: TelegramClient) {
 			while (rs.next()) {
 				result[if (rs.getInt(1) == 0) 6 else rs.getInt(1) - 1][rs.getInt(2)] = rs.getInt(3)
 			}
+			rs.close()
 			return result
 		} catch (e: Exception) {
 			throw RuntimeException(e)

src/main/kotlin/de/fabianonline/telegram_backup/DatabaseUpdates.kt

@@ -37,25 +37,19 @@ class DatabaseUpdates(protected var conn: Connection, protected var db: Database
 	fun doUpdates() {
 		try {
 			val stmt = conn.createStatement()
-			var rs: ResultSet
 			logger.debug("DatabaseUpdate.doUpdates running")
 
 			logger.debug("Getting current database version")
 			var version: Int
 			logger.debug("Checking if table database_versions exists")
-			rs = stmt.executeQuery("SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='database_versions'")
+			val table_count = db.queryInt("SELECT COUNT(*) FROM sqlite_master WHERE type='table' AND name='database_versions'")
-			rs.next()
+			if (table_count == 0) {
-			if (rs.getInt(1) == 0) {
 				logger.debug("Table does not exist")
 				version = 0
 			} else {
 				logger.debug("Table exists. Checking max version")
-				rs.close()
+				version = db.queryInt("SELECT MAX(version) FROM database_versions")
-				rs = stmt.executeQuery("SELECT MAX(version) FROM database_versions")
-				rs.next()
-				version = rs.getInt(1)
 			}
-			rs.close()
 			logger.debug("version: {}", version)
 			System.out.println("Database version: " + version)
 			logger.debug("Max available database version is {}", maxPossibleVersion)
@@ -106,6 +100,9 @@ class DatabaseUpdates(protected var conn: Connection, protected var db: Database
 				} catch (e: SQLException) {
 					throw RuntimeException(e)
 				}
+				
+				println("Cleaning up the database (this might take some time)...")
+				try { stmt.executeUpdate("VACUUM") } catch (t: Throwable) { logger.debug("Exception during VACUUMing: {}", t) }
 
 			} else {
 				logger.debug("No update necessary.")
@@ -441,7 +438,5 @@ internal class DB_Update_9(conn: Connection, db: Database) : DatabaseUpdate(conn
 		}
 		println()
 		logger.info("Converted ${i} of ${count} messages.")
-		println("    Cleaning up the database (this might also take some time, sorry)...")
-		execute("VACUUM")
 	}
 }