10 files changed, 809 insertions, 205 deletions
diff --git a/phpBB/includes/db/db_tools.php b/phpBB/includes/db/db_tools.php
index f4b181c6ad..c6dd23e6bd 100644
--- a/phpBB/includes/db/db_tools.php
+++ b/phpBB/includes/db/db_tools.php
@@ -348,6 +348,66 @@ class phpbb_db_tools
 	}
 
 	/**
+	* Gets a list of tables in the database.
+	*
+	* @return array		Array of table names  (all lower case)
+	*/
+	function sql_list_tables()
+	{
+		switch ($this->db->sql_layer)
+		{
+			case 'mysql':
+			case 'mysql4':
+			case 'mysqli':
+				$sql = 'SHOW TABLES';
+			break;
+
+			case 'sqlite':
+				$sql = 'SELECT name
+					FROM sqlite_master
+					WHERE type = "table"';
+			break;
+
+			case 'mssql':
+			case 'mssql_odbc':
+			case 'mssqlnative':
+				$sql = "SELECT name
+					FROM sysobjects
+					WHERE type='U'";
+			break;
+
+			case 'postgres':
+				$sql = 'SELECT relname
+					FROM pg_stat_user_tables';
+			break;
+
+			case 'firebird':
+				$sql = 'SELECT rdb$relation_name
+					FROM rdb$relations
+					WHERE rdb$view_source is null
+						AND rdb$system_flag = 0';
+			break;
+
+			case 'oracle':
+				$sql = 'SELECT table_name
+					FROM USER_TABLES';
+			break;
+		}
+
+		$result = $this->db->sql_query($sql);
+
+		$tables = array();
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			$name = current($row);
+			$tables[$name] = $name;
+		}
+		$this->db->sql_freeresult($result);
+
+		return $tables;
+	}
+
+	/**
 	* Check if table exists
 	*
 	*
@@ -417,6 +477,11 @@ class phpbb_db_tools
 			// here lies an array, filled with information compiled on the column's data
 			$prepared_column = $this->sql_prepare_column_data($table_name, $column_name, $column_data);
 
+			if (isset($prepared_column['auto_increment']) && strlen($column_name) > 26) // "${column_name}_gen"
+			{
+				trigger_error("Index name '${column_name}_gen' on table '$table_name' is too long. The maximum auto increment column length is 26 characters.", E_USER_ERROR);
+			}
+
 			// here we add the definition of the new column to the list of columns
 			switch ($this->sql_layer)
 			{
@@ -538,7 +603,7 @@ class phpbb_db_tools
 			break;
 
 			case 'oracle':
-				$table_sql .= "\n);";
+				$table_sql .= "\n)";
 				$statements[] = $table_sql;
 
 				// do we need to add a sequence and a tigger for auto incrementing columns?
@@ -556,7 +621,7 @@ class phpbb_db_tools
 					$trigger .= "BEGIN\n";
 					$trigger .= "\tSELECT {$table_name}_seq.nextval\n";
 					$trigger .= "\tINTO :new.{$create_sequence}\n";
-					$trigger .= "\tFROM dual\n";
+					$trigger .= "\tFROM dual;\n";
 					$trigger .= "END;";
 
 					$statements[] = $trigger;
@@ -566,7 +631,13 @@ class phpbb_db_tools
 			case 'firebird':
 				if ($create_sequence)
 				{
-					$statements[] = "CREATE SEQUENCE {$table_name}_seq;";
+					$statements[] = "CREATE GENERATOR {$table_name}_gen;";
+					$statements[] = "SET GENERATOR {$table_name}_gen TO 0;";
+
+					$trigger = "CREATE TRIGGER t_$table_name FOR $table_name\n";
+					$trigger .= "BEFORE INSERT\nAS\nBEGIN\n";
+					$trigger .= "\tNEW.{$create_sequence} = GEN_ID({$table_name}_gen, 1);\nEND;";
+					$statements[] = $trigger;
 				}
 			break;
 		}
@@ -638,6 +709,36 @@ class phpbb_db_tools
 			$sqlite = true;
 		}
 
+		// Drop tables?
+		if (!empty($schema_changes['drop_tables']))
+		{
+			foreach ($schema_changes['drop_tables'] as $table)
+			{
+				// only drop table if it exists
+				if ($this->sql_table_exists($table))
+				{
+					$result = $this->sql_table_drop($table);
+					if ($this->return_statements)
+					{
+						$statements = array_merge($statements, $result);
+					}
+				}
+			}
+		}
+
+		// Add tables?
+		if (!empty($schema_changes['add_tables']))
+		{
+			foreach ($schema_changes['add_tables'] as $table => $table_data)
+			{
+				$result = $this->sql_create_table($table, $table_data);
+				if ($this->return_statements)
+				{
+					$statements = array_merge($statements, $result);
+				}
+			}
+		}
+
 		// Change columns?
 		if (!empty($schema_changes['change_columns']))
 		{
@@ -681,10 +782,12 @@ class phpbb_db_tools
 			{
 				foreach ($columns as $column_name => $column_data)
 				{
-					// Only add the column if it does not exist yet, else change it (to be consistent)
+					// Only add the column if it does not exist yet
 					if ($column_exists = $this->sql_column_exists($table, $column_name))
 					{
-						$result = $this->sql_column_change($table, $column_name, $column_data, true);
+						continue;
+						// This is commented out here because it can take tremendous time on updates
+//						$result = $this->sql_column_change($table, $column_name, $column_data, true);
 					}
 					else
 					{
@@ -695,7 +798,8 @@ class phpbb_db_tools
 					{
 						if ($column_exists)
 						{
-							$sqlite_data[$table]['change_columns'][] = $result;
+							continue;
+//							$sqlite_data[$table]['change_columns'][] = $result;
 						}
 						else
 						{
@@ -717,6 +821,11 @@ class phpbb_db_tools
 			{
 				foreach ($indexes as $index_name)
 				{
+					if (!$this->sql_index_exists($table, $index_name))
+					{
+						continue;
+					}
+
 					$result = $this->sql_index_drop($table, $index_name);
 
 					if ($this->return_statements)
@@ -777,6 +886,11 @@ class phpbb_db_tools
 			{
 				foreach ($index_array as $index_name => $column)
 				{
+					if ($this->sql_unique_index_exists($table, $index_name))
+					{
+						continue;
+					}
+
 					$result = $this->sql_create_unique_index($table, $index_name, $column);
 
 					if ($this->return_statements)
@@ -794,6 +908,11 @@ class phpbb_db_tools
 			{
 				foreach ($index_array as $index_name => $column)
 				{
+					if ($this->sql_index_exists($table, $index_name))
+					{
+						continue;
+					}
+
 					$result = $this->sql_create_index($table, $index_name, $column);
 
 					if ($this->return_statements)
@@ -952,34 +1071,21 @@ class phpbb_db_tools
 	}
 
 	/**
-	* Check if a specified column exist
+	* Gets a list of columns of a table.
 	*
-	* @param string	$table			Table to check the column at
-	* @param string	$column_name	The column to check
+	* @param string $table		Table name
 	*
-	* @return bool True if column exists, else false
+	* @return array				Array of column names (all lower case)
 	*/
-	function sql_column_exists($table, $column_name)
+	function sql_list_columns($table)
 	{
+		$columns = array();
+
 		switch ($this->sql_layer)
 		{
 			case 'mysql_40':
 			case 'mysql_41':
-
 				$sql = "SHOW COLUMNS FROM $table";
-				$result = $this->db->sql_query($sql);
-
-				while ($row = $this->db->sql_fetchrow($result))
-				{
-					// lower case just in case
-					if (strtolower($row['Field']) == $column_name)
-					{
-						$this->db->sql_freeresult($result);
-						return true;
-					}
-				}
-				$this->db->sql_freeresult($result);
-				return false;
 			break;
 
 			// PostgreSQL has a way of doing this in a much simpler way but would
@@ -990,19 +1096,6 @@ class phpbb_db_tools
 					WHERE c.relname = '{$table}'
 						AND a.attnum > 0
 						AND a.attrelid = c.oid";
-				$result = $this->db->sql_query($sql);
-				while ($row = $this->db->sql_fetchrow($result))
-				{
-					// lower case just in case
-					if (strtolower($row['attname']) == $column_name)
-					{
-						$this->db->sql_freeresult($result);
-						return true;
-					}
-				}
-				$this->db->sql_freeresult($result);
-
-				return false;
 			break;
 
 			// same deal with PostgreSQL, we must perform more complex operations than
@@ -1013,62 +1106,26 @@ class phpbb_db_tools
 					FROM syscolumns c
 					LEFT JOIN sysobjects o ON c.id = o.id
 					WHERE o.name = '{$table}'";
-				$result = $this->db->sql_query($sql);
-				while ($row = $this->db->sql_fetchrow($result))
-				{
-					// lower case just in case
-					if (strtolower($row['name']) == $column_name)
-					{
-						$this->db->sql_freeresult($result);
-						return true;
-					}
-				}
-				$this->db->sql_freeresult($result);
-				return false;
 			break;
 
 			case 'oracle':
 				$sql = "SELECT column_name
 					FROM user_tab_columns
 					WHERE LOWER(table_name) = '" . strtolower($table) . "'";
-				$result = $this->db->sql_query($sql);
-				while ($row = $this->db->sql_fetchrow($result))
-				{
-					// lower case just in case
-					if (strtolower($row['column_name']) == $column_name)
-					{
-						$this->db->sql_freeresult($result);
-						return true;
-					}
-				}
-				$this->db->sql_freeresult($result);
-				return false;
 			break;
 
 			case 'firebird':
 				$sql = "SELECT RDB\$FIELD_NAME as FNAME
 					FROM RDB\$RELATION_FIELDS
 					WHERE RDB\$RELATION_NAME = '" . strtoupper($table) . "'";
-				$result = $this->db->sql_query($sql);
-				while ($row = $this->db->sql_fetchrow($result))
-				{
-					// lower case just in case
-					if (strtolower($row['fname']) == $column_name)
-					{
-						$this->db->sql_freeresult($result);
-						return true;
-					}
-				}
-				$this->db->sql_freeresult($result);
-				return false;
 			break;
 
-			// ugh, SQLite
 			case 'sqlite':
 				$sql = "SELECT sql
 					FROM sqlite_master
 					WHERE type = 'table'
 						AND name = '{$table}'";
+
 				$result = $this->db->sql_query($sql);
 
 				if (!$result)
@@ -1092,14 +1149,269 @@ class phpbb_db_tools
 						continue;
 					}
 
-					if (strtolower($entities[0]) == $column_name)
+					$column = strtolower($entities[0]);
+					$columns[$column] = $column;
+				}
+
+				return $columns;
+			break;
+		}
+
+		$result = $this->db->sql_query($sql);
+
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			$column = strtolower(current($row));
+			$columns[$column] = $column;
+		}
+		$this->db->sql_freeresult($result);
+
+		return $columns;
+	}
+
+	/**
+	* Check whether a specified column exist in a table
+	*
+	* @param string	$table			Table to check
+	* @param string	$column_name	Column to check
+	*
+	* @return bool		True if column exists, false otherwise
+	*/
+	function sql_column_exists($table, $column_name)
+	{
+		$columns = $this->sql_list_columns($table);
+
+		return isset($columns[$column_name]);
+	}
+
+	/**
+	* Check if a specified index exists in table. Does not return PRIMARY KEY and UNIQUE indexes.
+	*
+	* @param string	$table_name		Table to check the index at
+	* @param string	$index_name		The index name to check
+	*
+	* @return bool True if index exists, else false
+	*/
+	function sql_index_exists($table_name, $index_name)
+	{
+		if ($this->sql_layer == 'mssql' || $this->sql_layer == 'mssqlnative')
+		{
+			$sql = "EXEC sp_statistics '$table_name'";
+			$result = $this->db->sql_query($sql);
+
+			while ($row = $this->db->sql_fetchrow($result))
+			{
+				if ($row['TYPE'] == 3)
+				{
+					if (strtolower($row['INDEX_NAME']) == strtolower($index_name))
 					{
+						$this->db->sql_freeresult($result);
 						return true;
 					}
 				}
-				return false;
+			}
+			$this->db->sql_freeresult($result);
+
+			return false;
+		}
+
+		switch ($this->sql_layer)
+		{
+			case 'firebird':
+				$sql = "SELECT LOWER(RDB\$INDEX_NAME) as index_name
+					FROM RDB\$INDICES
+					WHERE RDB\$RELATION_NAME = '" . strtoupper($table_name) . "'
+						AND RDB\$UNIQUE_FLAG IS NULL
+						AND RDB\$FOREIGN_KEY IS NULL";
+				$col = 'index_name';
+			break;
+
+			case 'postgres':
+				$sql = "SELECT ic.relname as index_name
+					FROM pg_class bc, pg_class ic, pg_index i
+					WHERE (bc.oid = i.indrelid)
+						AND (ic.oid = i.indexrelid)
+						AND (bc.relname = '" . $table_name . "')
+						AND (i.indisunique != 't')
+						AND (i.indisprimary != 't')";
+				$col = 'index_name';
+			break;
+
+			case 'mysql_40':
+			case 'mysql_41':
+				$sql = 'SHOW KEYS
+					FROM ' . $table_name;
+				$col = 'Key_name';
 			break;
+
+			case 'oracle':
+				$sql = "SELECT index_name
+					FROM user_indexes
+					WHERE table_name = '" . strtoupper($table_name) . "'
+						AND generated = 'N'
+						AND uniqueness = 'NONUNIQUE'";
+				$col = 'index_name';
+			break;
+
+			case 'sqlite':
+				$sql = "PRAGMA index_list('" . $table_name . "');";
+				$col = 'name';
+			break;
+		}
+
+		$result = $this->db->sql_query($sql);
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			if (($this->sql_layer == 'mysql_40' || $this->sql_layer == 'mysql_41') && !$row['Non_unique'])
+			{
+				continue;
+			}
+
+			// These DBMS prefix index name with the table name
+			switch ($this->sql_layer)
+			{
+				case 'firebird':
+				case 'oracle':
+				case 'postgres':
+				case 'sqlite':
+					$row[$col] = substr($row[$col], strlen($table_name) + 1);
+				break;
+			}
+
+			if (strtolower($row[$col]) == strtolower($index_name))
+			{
+				$this->db->sql_freeresult($result);
+				return true;
+			}
 		}
+		$this->db->sql_freeresult($result);
+
+		return false;
+	}
+
+	/**
+	* Check if a specified index exists in table. Does not return PRIMARY KEY and UNIQUE indexes.
+	*
+	* @param string	$table_name		Table to check the index at
+	* @param string	$index_name		The index name to check
+	*
+	* @return bool True if index exists, else false
+	*/
+	function sql_unique_index_exists($table_name, $index_name)
+	{
+		if ($this->sql_layer == 'mssql' || $this->sql_layer == 'mssqlnative')
+		{
+			$sql = "EXEC sp_statistics '$table_name'";
+			$result = $this->db->sql_query($sql);
+
+			while ($row = $this->db->sql_fetchrow($result))
+			{
+				// Usually NON_UNIQUE is the column we want to check, but we allow for both
+				if ($row['TYPE'] == 3)
+				{
+					if (strtolower($row['INDEX_NAME']) == strtolower($index_name))
+					{
+						$this->db->sql_freeresult($result);
+						return true;
+					}
+				}
+			}
+			$this->db->sql_freeresult($result);
+			return false;
+		}
+
+		switch ($this->sql_layer)
+		{
+			case 'firebird':
+				$sql = "SELECT LOWER(RDB\$INDEX_NAME) as index_name
+					FROM RDB\$INDICES
+					WHERE RDB\$RELATION_NAME = '" . strtoupper($table_name) . "'
+						AND RDB\$UNIQUE_FLAG IS NOT NULL
+						AND RDB\$FOREIGN_KEY IS NULL";
+				$col = 'index_name';
+			break;
+
+			case 'postgres':
+				$sql = "SELECT ic.relname as index_name, i.indisunique
+					FROM pg_class bc, pg_class ic, pg_index i
+					WHERE (bc.oid = i.indrelid)
+						AND (ic.oid = i.indexrelid)
+						AND (bc.relname = '" . $table_name . "')
+						AND (i.indisprimary != 't')";
+				$col = 'index_name';
+			break;
+
+			case 'mysql_40':
+			case 'mysql_41':
+				$sql = 'SHOW KEYS
+					FROM ' . $table_name;
+				$col = 'Key_name';
+			break;
+
+			case 'oracle':
+				$sql = "SELECT index_name, table_owner
+					FROM user_indexes
+					WHERE table_name = '" . strtoupper($table_name) . "'
+						AND generated = 'N'
+						AND uniqueness = 'UNIQUE'";
+				$col = 'index_name';
+			break;
+
+			case 'sqlite':
+				$sql = "PRAGMA index_list('" . $table_name . "');";
+				$col = 'name';
+			break;
+		}
+
+		$result = $this->db->sql_query($sql);
+		while ($row = $this->db->sql_fetchrow($result))
+		{
+			if (($this->sql_layer == 'mysql_40' || $this->sql_layer == 'mysql_41') && ($row['Non_unique'] || $row[$col] == 'PRIMARY'))
+			{
+				continue;
+			}
+
+			if ($this->sql_layer == 'sqlite' && !$row['unique'])
+			{
+				continue;
+			}
+
+			if ($this->sql_layer == 'postgres' && $row['indisunique'] != 't')
+			{
+				continue;
+			}
+
+			// These DBMS prefix index name with the table name
+			switch ($this->sql_layer)
+			{
+				case 'oracle':
+					// Two cases here... prefixed with U_[table_owner] and not prefixed with table_name
+					if (strpos($row[$col], 'U_') === 0)
+					{
+						$row[$col] = substr($row[$col], strlen('U_' . $row['table_owner']) + 1);
+					}
+					else if (strpos($row[$col], strtoupper($table_name)) === 0)
+					{
+						$row[$col] = substr($row[$col], strlen($table_name) + 1);
+					}
+				break;
+
+				case 'firebird':
+				case 'postgres':
+				case 'sqlite':
+					$row[$col] = substr($row[$col], strlen($table_name) + 1);
+				break;
+			}
+
+			if (strtolower($row[$col]) == strtolower($index_name))
+			{
+				$this->db->sql_freeresult($result);
+				return true;
+			}
+		}
+		$this->db->sql_freeresult($result);
+
+		return false;
 	}
 
 	/**
@@ -1139,6 +1451,11 @@ class phpbb_db_tools
 	*/
 	function sql_prepare_column_data($table_name, $column_name, $column_data)
 	{
+		if (strlen($column_name) > 30)
+		{
+			trigger_error("Column name '$column_name' on table '$table_name' is too long. The maximum is 30 characters.", E_USER_ERROR);
+		}
+
 		// Get type
 		if (strpos($column_data[0], ':') !== false)
 		{
@@ -1371,24 +1688,29 @@ class phpbb_db_tools
 		switch ($this->sql_layer)
 		{
 			case 'firebird':
+				// Does not support AFTER statement, only POSITION (and there you need the column position)
 				$statements[] = 'ALTER TABLE ' . $table_name . ' ADD "' . strtoupper($column_name) . '" ' . $column_data['column_type_sql'];
 			break;
 
 			case 'mssql':
 			case 'mssqlnative':
+				// Does not support AFTER, only through temporary table
 				$statements[] = 'ALTER TABLE [' . $table_name . '] ADD [' . $column_name . '] ' . $column_data['column_type_sql_default'];
 			break;
 
 			case 'mysql_40':
 			case 'mysql_41':
-				$statements[] = 'ALTER TABLE `' . $table_name . '` ADD COLUMN `' . $column_name . '` ' . $column_data['column_type_sql'];
+				$after = (!empty($column_data['after'])) ? ' AFTER ' . $column_data['after'] : '';
+				$statements[] = 'ALTER TABLE `' . $table_name . '` ADD COLUMN `' . $column_name . '` ' . $column_data['column_type_sql'] . $after;
 			break;
 
 			case 'oracle':
+				// Does not support AFTER, only through temporary table
 				$statements[] = 'ALTER TABLE ' . $table_name . ' ADD ' . $column_name . ' ' . $column_data['column_type_sql'];
 			break;
 
 			case 'postgres':
+				// Does not support AFTER, only through temporary table
 				if (version_compare($this->db->sql_server_info(true), '8.0', '>='))
 				{
 					$statements[] = 'ALTER TABLE ' . $table_name . ' ADD COLUMN "' . $column_name . '" ' . $column_data['column_type_sql'];
@@ -1506,7 +1828,7 @@ class phpbb_db_tools
 			break;
 
 			case 'oracle':
-				$statements[] = 'ALTER TABLE ' . $table_name . ' DROP ' . $column_name;
+				$statements[] = 'ALTER TABLE ' . $table_name . ' DROP COLUMN ' . $column_name;
 			break;
 
 			case 'postgres':
@@ -1657,6 +1979,7 @@ class phpbb_db_tools
 					$statements[] = "DROP SEQUENCE {$row['referenced_name']}";
 				}
 				$this->db->sql_freeresult($result);
+			break;
 
 			case 'postgres':
 				// PGSQL does not "tightly" bind sequences and tables, we must guess...
@@ -1774,6 +2097,13 @@ class phpbb_db_tools
 	{
 		$statements = array();
 
+		$table_prefix = substr(CONFIG_TABLE, 0, -6); // strlen(config)
+		if (strlen($table_name . $index_name) - strlen($table_prefix) > 24)
+		{
+			$max_length = strlen($table_prefix) + 24;
+			trigger_error("Index name '{$table_name}_$index_name' on table '$table_name' is too long. The maximum is $max_length characters.", E_USER_ERROR);
+		}
+
 		switch ($this->sql_layer)
 		{
 			case 'firebird':
@@ -1785,7 +2115,7 @@ class phpbb_db_tools
 
 			case 'mysql_40':
 			case 'mysql_41':
-				$statements[] = 'CREATE UNIQUE INDEX ' . $index_name . ' ON ' . $table_name . '(' . implode(', ', $column) . ')';
+				$statements[] = 'ALTER TABLE ' . $table_name . ' ADD UNIQUE INDEX ' . $index_name . '(' . implode(', ', $column) . ')';
 			break;
 
 			case 'mssql':
@@ -1804,6 +2134,13 @@ class phpbb_db_tools
 	{
 		$statements = array();
 
+		$table_prefix = substr(CONFIG_TABLE, 0, -6); // strlen(config)
+		if (strlen($table_name . $index_name) - strlen($table_prefix) > 24)
+		{
+			$max_length = strlen($table_prefix) + 24;
+			trigger_error("Index name '{$table_name}_$index_name' on table '$table_name' is too long. The maximum is $max_length characters.", E_USER_ERROR);
+		}
+
 		// remove index length unless MySQL4
 		if ('mysql_40' != $this->sql_layer)
 		{
@@ -1831,7 +2168,7 @@ class phpbb_db_tools
 				}
 			// no break
 			case 'mysql_41':
-				$statements[] = 'CREATE INDEX ' . $index_name . ' ON ' . $table_name . '(' . implode(', ', $column) . ')';
+				$statements[] = 'ALTER TABLE ' . $table_name . ' ADD INDEX ' . $index_name . '(' . implode(', ', $column) . ')';
 			break;
 
 			case 'mssql':
@@ -1957,6 +2294,7 @@ class phpbb_db_tools
 				}
 				else
 				{
+					// TODO: try to change pkey without removing trigger, generator or constraints. ATM this query may fail.
 					$statements[] = 'ALTER TABLE ' . $table_name . ' ALTER COLUMN "' . strtoupper($column_name) . '" TYPE ' . ' ' . $column_data['column_type_sql_type'];
 				}
 			break;
diff --git a/phpBB/includes/db/dbal.php b/phpBB/includes/db/dbal.php
index eeddf1f41b..9cc337955b 100644
--- a/phpBB/includes/db/dbal.php
+++ b/phpBB/includes/db/dbal.php
@@ -195,6 +195,49 @@ class dbal
 	}
 
 	/**
+	* Seek to given row number
+	* rownum is zero-based
+	*/
+	function sql_rowseek($rownum, &$query_id)
+	{
+		global $cache;
+
+		if ($query_id === false)
+		{
+			$query_id = $this->query_result;
+		}
+
+		if (isset($cache->sql_rowset[$query_id]))
+		{
+			return $cache->sql_rowseek($rownum, $query_id);
+		}
+
+		if ($query_id === false)
+		{
+			return false;
+		}
+
+		$this->sql_freeresult($query_id);
+		$query_id = $this->sql_query($this->last_query_text);
+
+		if ($query_id === false)
+		{
+			return false;
+		}
+
+		// We do not fetch the row for rownum == 0 because then the next resultset would be the second row
+		for ($i = 0; $i < $rownum; $i++)
+		{
+			if (!$this->sql_fetchrow($query_id))
+			{
+				return false;
+			}
+		}
+
+		return true;
+	}
+
+	/**
 	* Fetch field
 	* if rownum is false, the current row is used, else it is pointing to the row (zero-based)
 	*/
@@ -242,6 +285,16 @@ class dbal
 	}
 
 	/**
+	* Returns whether results of a query need to be buffered to run a transaction while iterating over them.
+	*
+	* @return bool Whether buffering is required.
+	*/
+	function sql_buffer_nested_transactions()
+	{
+		return false;
+	}
+
+	/**
 	* SQL Transaction
 	* @access private
 	*/
@@ -448,6 +501,18 @@ class dbal
 	}
 
 	/**
+	* Run LOWER() on DB column of type text (i.e. neither varchar nor char).
+	*
+	* @param string $column_name	The column name to use
+	*
+	* @return string				A SQL statement like "LOWER($column_name)"
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER($column_name)";
+	}
+
+	/**
 	* Run more than one insert statement.
 	*
 	* @param string $table table name to run the statements on
@@ -599,7 +664,7 @@ class dbal
 					}
 				}
 
-				$sql .= $this->_sql_custom_build('FROM', implode(', ', $table_array));
+				$sql .= $this->_sql_custom_build('FROM', implode(' CROSS JOIN ', $table_array));
 
 				if (!empty($array['LEFT_JOIN']))
 				{
@@ -652,12 +717,7 @@ class dbal
 			// The DEBUG_EXTRA constant is for development only!
 			if ((isset($auth) && $auth->acl_get('a_')) || defined('IN_INSTALL') || defined('DEBUG_EXTRA'))
 			{
-				// Print out a nice backtrace...
-				$backtrace = get_backtrace();
-
 				$message .= ($sql) ? '<br /><br />SQL<br /><br />' . htmlspecialchars($sql) : '';
-				$message .= ($backtrace) ? '<br /><br />BACKTRACE<br />' . $backtrace : '';
-				$message .= '<br />';
 			}
 			else
 			{
@@ -767,7 +827,7 @@ class dbal
 							</div>
 						</div>
 						<div id="page-footer">
-							Powered by phpBB &copy; 2000, 2002, 2005, 2007 <a href="http://www.phpbb.com/">phpBB Group</a>
+							Powered by <a href="http://www.phpbb.com/">phpBB</a>&reg; Forum Software &copy; phpBB Group
 						</div>
 					</div>
 					</body>
@@ -895,6 +955,41 @@ class dbal
 
 		return true;
 	}
+
+	/**
+	* Gets the estimated number of rows in a specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return string				Number of rows in $table_name.
+	*								Prefixed with ~ if estimated (otherwise exact).
+	*
+	* @access public
+	*/
+	function get_estimated_row_count($table_name)
+	{
+		return $this->get_row_count($table_name);
+	}
+
+	/**
+	* Gets the exact number of rows in a specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return string				Exact number of rows in $table_name.
+	*
+	* @access public
+	*/
+	function get_row_count($table_name)
+	{
+		$sql = 'SELECT COUNT(*) AS rows_total
+			FROM ' . $this->sql_escape($table_name);
+		$result = $this->sql_query($sql);
+		$rows_total = $this->sql_fetchfield('rows_total');
+		$this->sql_freeresult($result);
+
+		return $rows_total;
+	}
 }
 
 /**
diff --git a/phpBB/includes/db/firebird.php b/phpBB/includes/db/firebird.php
index 6f60dd5dad..7072c58ac0 100644
--- a/phpBB/includes/db/firebird.php
+++ b/phpBB/includes/db/firebird.php
@@ -28,6 +28,7 @@ class dbal_firebird extends dbal
 	var $last_query_text = '';
 	var $service_handle = false;
 	var $affected_rows = 0;
+	var $connect_error = '';
 
 	/**
 	* Connect to server
@@ -53,9 +54,35 @@ class dbal_firebird extends dbal
 			$use_database = $this->server . ':' . $this->dbname;
 		}
 
-		$this->db_connect_id = ($this->persistency) ? @ibase_pconnect($use_database, $this->user, $sqlpassword, false, false, 3) : @ibase_connect($use_database, $this->user, $sqlpassword, false, false, 3);
+		if ($this->persistency)
+		{
+			if (!function_exists('ibase_pconnect'))
+			{
+				$this->connect_error = 'ibase_pconnect function does not exist, is interbase extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @ibase_pconnect($use_database, $this->user, $sqlpassword, false, false, 3);
+		}
+		else
+		{
+			if (!function_exists('ibase_connect'))
+			{
+				$this->connect_error = 'ibase_connect function does not exist, is interbase extension installed?';
+				return $this->sql_error('');
+			}
+			$this->db_connect_id = @ibase_connect($use_database, $this->user, $sqlpassword, false, false, 3);
+		}
 
-		$this->service_handle = (function_exists('ibase_service_attach') && $this->server) ? @ibase_service_attach($this->server, $this->user, $sqlpassword) : false;
+		// Do not call ibase_service_attach if connection failed,
+		// otherwise error message from ibase_(p)connect call will be clobbered.
+		if ($this->db_connect_id && function_exists('ibase_service_attach') && $this->server)
+		{
+			$this->service_handle = @ibase_service_attach($this->server, $this->user, $sqlpassword);
+		}
+		else
+		{
+			$this->service_handle = false;
+		}
 
 		return ($this->db_connect_id) ? $this->db_connect_id : $this->sql_error('');
 	}
@@ -333,49 +360,6 @@ class dbal_firebird extends dbal
 	}
 
 	/**
-	* Seek to given row number
-	* rownum is zero-based
-	*/
-	function sql_rowseek($rownum, &$query_id)
-	{
-		global $cache;
-
-		if ($query_id === false)
-		{
-			$query_id = $this->query_result;
-		}
-
-		if (isset($cache->sql_rowset[$query_id]))
-		{
-			return $cache->sql_rowseek($rownum, $query_id);
-		}
-
-		if ($query_id === false)
-		{
-			return;
-		}
-
-		$this->sql_freeresult($query_id);
-		$query_id = $this->sql_query($this->last_query_text);
-
-		if ($query_id === false)
-		{
-			return false;
-		}
-
-		// We do not fetch the row for rownum == 0 because then the next resultset would be the second row
-		for ($i = 0; $i < $rownum; $i++)
-		{
-			if (!$this->sql_fetchrow($query_id))
-			{
-				return false;
-			}
-		}
-
-		return true;
-	}
-
-	/**
 	* Get last inserted id after insert statement
 	*/
 	function sql_nextid()
@@ -471,8 +455,24 @@ class dbal_firebird extends dbal
 	*/
 	function _sql_error()
 	{
+		// Need special handling here because ibase_errmsg returns
+		// connection errors, however if the interbase extension
+		// is not installed then ibase_errmsg does not exist and
+		// we cannot call it.
+		if (function_exists('ibase_errmsg'))
+		{
+			$msg = @ibase_errmsg();
+			if (!$msg)
+			{
+				$msg = $this->connect_error;
+			}
+		}
+		else
+		{
+			$msg = $this->connect_error;
+		}
 		return array(
-			'message'	=> @ibase_errmsg(),
+			'message'	=> $msg,
 			'code'		=> (@function_exists('ibase_errcode') ? @ibase_errcode() : '')
 		);
 	}
diff --git a/phpBB/includes/db/mssql.php b/phpBB/includes/db/mssql.php
index 6899a73902..b7178593dc 100644
--- a/phpBB/includes/db/mssql.php
+++ b/phpBB/includes/db/mssql.php
@@ -333,6 +333,14 @@ class dbal_mssql extends dbal
 	}
 
 	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER(SUBSTRING($column_name, 1, DATALENGTH($column_name)))";
+	}
+
+	/**
 	* Build LIKE expression
 	* @access private
 	*/
diff --git a/phpBB/includes/db/mssql_odbc.php b/phpBB/includes/db/mssql_odbc.php
index 75a080b1b7..2ecc42cadf 100644
--- a/phpBB/includes/db/mssql_odbc.php
+++ b/phpBB/includes/db/mssql_odbc.php
@@ -256,49 +256,6 @@ class dbal_mssql_odbc extends dbal
 	}
 
 	/**
-	* Seek to given row number
-	* rownum is zero-based
-	*/
-	function sql_rowseek($rownum, &$query_id)
-	{
-		global $cache;
-
-		if ($query_id === false)
-		{
-			$query_id = $this->query_result;
-		}
-
-		if (isset($cache->sql_rowset[$query_id]))
-		{
-			return $cache->sql_rowseek($rownum, $query_id);
-		}
-
-		if ($query_id === false)
-		{
-			return false;
-		}
-
-		$this->sql_freeresult($query_id);
-		$query_id = $this->sql_query($this->last_query_text);
-
-		if ($query_id === false)
-		{
-			return false;
-		}
-
-		// We do not fetch the row for rownum == 0 because then the next resultset would be the second row
-		for ($i = 0; $i < $rownum; $i++)
-		{
-			if (!$this->sql_fetchrow($query_id))
-			{
-				return false;
-			}
-		}
-
-		return true;
-	}
-
-	/**
 	* Get last inserted id after insert statement
 	*/
 	function sql_nextid()
@@ -354,6 +311,14 @@ class dbal_mssql_odbc extends dbal
 	}
 
 	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER(SUBSTRING($column_name, 1, DATALENGTH($column_name)))";
+	}
+
+	/**
 	* Build LIKE expression
 	* @access private
 	*/
diff --git a/phpBB/includes/db/mssqlnative.php b/phpBB/includes/db/mssqlnative.php
index 7ed4146f27..c91cc188b0 100644
--- a/phpBB/includes/db/mssqlnative.php
+++ b/phpBB/includes/db/mssqlnative.php
@@ -50,7 +50,7 @@ class result_mssqlnative
 			}
 		}
 
-		$this->m_row_count = count($this->m_rows);
+		$this->m_row_count = sizeof($this->m_rows);
 	}
 
 	private function array_to_obj($array, &$obj)
@@ -259,6 +259,14 @@ class dbal_mssqlnative extends dbal
 	}
 
 	/**
+	* {@inheritDoc}
+	*/
+	function sql_buffer_nested_transactions()
+	{
+		return true;
+	}
+
+	/**
 	* SQL Transaction
 	* @access private
 	*/
@@ -388,7 +396,7 @@ class dbal_mssqlnative extends dbal
 	*/
 	function sql_affectedrows()
 	{
-		return ($this->db_connect_id) ? @sqlsrv_rows_affected($this->db_connect_id) : false;
+		return (!empty($this->query_result)) ? @sqlsrv_rows_affected($this->query_result) : false;
 	}
 
 	/**
@@ -432,24 +440,6 @@ class dbal_mssqlnative extends dbal
 	}
 
 	/**
-	* Seek to given row number
-	* rownum is zero-based
-	*/
-	function sql_rowseek($rownum, &$query_id)
-	{
-		global $cache;
-
-		if (isset($cache->sql_rowset[$query_id]))
-		{
-			return $cache->sql_rowseek($rownum, $query_id);
-		}
-
-		$seek = new result_mssqlnative($query_id);
-		$row = $seek->seek($rownum);
-		return ($row = $seek->fetch()) ? $row : false;
-	}
-
-	/**
 	* Get last inserted id after insert statement
 	*/
 	function sql_nextid()
@@ -503,6 +493,14 @@ class dbal_mssqlnative extends dbal
 	}
 
 	/**
+	* {@inheritDoc}
+	*/
+	function sql_lower_text($column_name)
+	{
+		return "LOWER(SUBSTRING($column_name, 1, DATALENGTH($column_name)))";
+	}
+
+	/**
 	* Build LIKE expression
 	* @access private
 	*/
@@ -628,7 +626,7 @@ class dbal_mssqlnative extends dbal
 			return false;
 		}
 	}
-	
+
 	/**
 	* Allows setting mssqlnative specific query options passed to sqlsrv_query as 4th parameter.
 	*/
diff --git a/phpBB/includes/db/mysql.php b/phpBB/includes/db/mysql.php
index 1e24c79577..1ccb785150 100644
--- a/phpBB/includes/db/mysql.php
+++ b/phpBB/includes/db/mysql.php
@@ -319,6 +319,76 @@ class dbal_mysql extends dbal
 	}
 
 	/**
+	* Gets the estimated number of rows in a specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return string				Number of rows in $table_name.
+	*								Prefixed with ~ if estimated (otherwise exact).
+	*
+	* @access public
+	*/
+	function get_estimated_row_count($table_name)
+	{
+		$table_status = $this->get_table_status($table_name);
+
+		if (isset($table_status['Engine']))
+		{
+			if ($table_status['Engine'] === 'MyISAM')
+			{
+				return $table_status['Rows'];
+			}
+			else if ($table_status['Engine'] === 'InnoDB' && $table_status['Rows'] > 100000)
+			{
+				return '~' . $table_status['Rows'];
+			}
+		}
+
+		return parent::get_row_count($table_name);
+	}
+
+	/**
+	* Gets the exact number of rows in a specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return string				Exact number of rows in $table_name.
+	*
+	* @access public
+	*/
+	function get_row_count($table_name)
+	{
+		$table_status = $this->get_table_status($table_name);
+
+		if (isset($table_status['Engine']) && $table_status['Engine'] === 'MyISAM')
+		{
+			return $table_status['Rows'];
+		}
+
+		return parent::get_row_count($table_name);
+	}
+
+	/**
+	* Gets some information about the specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return array
+	*
+	* @access protected
+	*/
+	function get_table_status($table_name)
+	{
+		$sql = "SHOW TABLE STATUS
+			LIKE '" . $this->sql_escape($table_name) . "'";
+		$result = $this->sql_query($sql);
+		$table_status = $this->sql_fetchrow($result);
+		$this->sql_freeresult($result);
+
+		return $table_status;
+	}
+
+	/**
 	* Build LIKE expression
 	* @access private
 	*/
diff --git a/phpBB/includes/db/mysqli.php b/phpBB/includes/db/mysqli.php
index 862d62f4ba..a311b8cda6 100644
--- a/phpBB/includes/db/mysqli.php
+++ b/phpBB/includes/db/mysqli.php
@@ -33,14 +33,33 @@ class dbal_mysqli extends dbal
 	*/
 	function sql_connect($sqlserver, $sqluser, $sqlpassword, $database, $port = false, $persistency = false , $new_link = false)
 	{
-		$this->persistency = $persistency;
+		// Mysqli extension supports persistent connection since PHP 5.3.0
+		$this->persistency = (version_compare(PHP_VERSION, '5.3.0', '>=')) ? $persistency : false;
 		$this->user = $sqluser;
-		$this->server = $sqlserver;
+
+		// If persistent connection, set dbhost to localhost when empty and prepend it with 'p:' prefix
+		$this->server = ($this->persistency) ? 'p:' . (($sqlserver) ? $sqlserver : 'localhost') : $sqlserver;
+
 		$this->dbname = $database;
 		$port = (!$port) ? NULL : $port;
 
-		// Persistant connections not supported by the mysqli extension?
-		$this->db_connect_id = @mysqli_connect($this->server, $this->user, $sqlpassword, $this->dbname, $port);
+		// If port is set and it is not numeric, most likely mysqli socket is set.
+		// Try to map it to the $socket parameter.
+		$socket = NULL;
+		if ($port)
+		{
+			if (is_numeric($port))
+			{
+				$port = (int) $port;
+			}
+			else
+			{
+				$socket = $port;
+				$port = NULL;
+			}
+		}
+
+		$this->db_connect_id = @mysqli_connect($this->server, $this->user, $sqlpassword, $this->dbname, $port, $socket);
 
 		if ($this->db_connect_id && $this->dbname != '')
 		{
@@ -230,7 +249,13 @@ class dbal_mysqli extends dbal
 			return $cache->sql_fetchrow($query_id);
 		}
 
-		return ($query_id !== false) ? @mysqli_fetch_assoc($query_id) : false;
+		if ($query_id !== false)
+		{
+			$result = @mysqli_fetch_assoc($query_id);
+			return $result !== null ? $result : false;
+		}
+
+		return false;
 	}
 
 	/**
@@ -291,6 +316,76 @@ class dbal_mysqli extends dbal
 	}
 
 	/**
+	* Gets the estimated number of rows in a specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return string				Number of rows in $table_name.
+	*								Prefixed with ~ if estimated (otherwise exact).
+	*
+	* @access public
+	*/
+	function get_estimated_row_count($table_name)
+	{
+		$table_status = $this->get_table_status($table_name);
+
+		if (isset($table_status['Engine']))
+		{
+			if ($table_status['Engine'] === 'MyISAM')
+			{
+				return $table_status['Rows'];
+			}
+			else if ($table_status['Engine'] === 'InnoDB' && $table_status['Rows'] > 100000)
+			{
+				return '~' . $table_status['Rows'];
+			}
+		}
+
+		return parent::get_row_count($table_name);
+	}
+
+	/**
+	* Gets the exact number of rows in a specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return string				Exact number of rows in $table_name.
+	*
+	* @access public
+	*/
+	function get_row_count($table_name)
+	{
+		$table_status = $this->get_table_status($table_name);
+
+		if (isset($table_status['Engine']) && $table_status['Engine'] === 'MyISAM')
+		{
+			return $table_status['Rows'];
+		}
+
+		return parent::get_row_count($table_name);
+	}
+
+	/**
+	* Gets some information about the specified table.
+	*
+	* @param string $table_name		Table name
+	*
+	* @return array
+	*
+	* @access protected
+	*/
+	function get_table_status($table_name)
+	{
+		$sql = "SHOW TABLE STATUS
+			LIKE '" . $this->sql_escape($table_name) . "'";
+		$result = $this->sql_query($sql);
+		$table_status = $this->sql_fetchrow($result);
+		$this->sql_freeresult($result);
+
+		return $table_status;
+	}
+
+	/**
 	* Build LIKE expression
 	* @access private
 	*/
diff --git a/phpBB/includes/db/oracle.php b/phpBB/includes/db/oracle.php
index c8a9a5f604..62b36aa8bf 100644
--- a/phpBB/includes/db/oracle.php
+++ b/phpBB/includes/db/oracle.php
@@ -269,11 +269,12 @@ class dbal_oracle extends dbal
 						{
 							$cols = explode(', ', $regs[2]);
 
+							preg_match_all('/\'(?:[^\']++|\'\')*+\'|[\d-.]+/', $regs[3], $vals, PREG_PATTERN_ORDER);
+
 /*						The code inside this comment block breaks clob handling, but does allow the
 						database restore script to work.  If you want to allow no posts longer than 4KB
 						and/or need the db restore script, uncomment this.
 
-							preg_match_all('/\'(?:[^\']++|\'\')*+\'|[\d-.]+/', $regs[3], $vals, PREG_PATTERN_ORDER);
 
 							if (sizeof($cols) !== sizeof($vals))
 							{
diff --git a/phpBB/includes/db/postgres.php b/phpBB/includes/db/postgres.php
index 4360c790a1..bb116e0763 100644
--- a/phpBB/includes/db/postgres.php
+++ b/phpBB/includes/db/postgres.php
@@ -18,6 +18,11 @@ if (!defined('IN_PHPBB'))
 
 include_once($phpbb_root_path . 'includes/db/dbal.' . $phpEx);
 
+if (!class_exists('phpbb_error_collector'))
+{
+	include($phpbb_root_path . 'includes/error_collector.' . $phpEx);
+}
+
 /**
 * PostgreSQL Database Abstraction Layer
 * Minimum Requirement is Version 7.3+
@@ -26,6 +31,7 @@ include_once($phpbb_root_path . 'includes/db/dbal.' . $phpEx);
 class dbal_postgres extends dbal
 {
 	var $last_query_text = '';
+	var $connect_error = '';
 
 	/**
 	* Connect to server
@@ -81,13 +87,29 @@ class dbal_postgres extends dbal
 
 		if ($this->persistency)
 		{
+			if (!function_exists('pg_pconnect'))
+			{
+				$this->connect_error = 'pg_pconnect function does not exist, is pgsql extension installed?';
+				return $this->sql_error('');
+			}
+			$collector = new phpbb_error_collector;
+			$collector->install();
 			$this->db_connect_id = (!$new_link) ? @pg_pconnect($connect_string) : @pg_pconnect($connect_string, PGSQL_CONNECT_FORCE_NEW);
 		}
 		else
 		{
+			if (!function_exists('pg_connect'))
+			{
+				$this->connect_error = 'pg_connect function does not exist, is pgsql extension installed?';
+				return $this->sql_error('');
+			}
+			$collector = new phpbb_error_collector;
+			$collector->install();
 			$this->db_connect_id = (!$new_link) ? @pg_connect($connect_string) : @pg_connect($connect_string, PGSQL_CONNECT_FORCE_NEW);
 		}
 
+		$collector->uninstall();
+
 		if ($this->db_connect_id)
 		{
 			if (version_compare($this->sql_server_info(true), '8.2', '>='))
@@ -102,6 +124,7 @@ class dbal_postgres extends dbal
 			return $this->db_connect_id;
 		}
 
+		$this->connect_error = $collector->format_errors();
 		return $this->sql_error('');
 	}
 
@@ -371,8 +394,19 @@ class dbal_postgres extends dbal
 	*/
 	function _sql_error()
 	{
+		// pg_last_error only works when there is an established connection.
+		// Connection errors have to be tracked by us manually.
+		if ($this->db_connect_id)
+		{
+			$message = @pg_last_error($this->db_connect_id);
+		}
+		else
+		{
+			$message = $this->connect_error;
+		}
+
 		return array(
-			'message'	=> (!$this->db_connect_id) ? @pg_last_error() : @pg_last_error($this->db_connect_id),
+			'message'	=> $message,
 			'code'		=> ''
 		);
 	}