G MySQL に将来加えたいもの (The TODO)

このリストのすべては、それが終わるだろう順番に書かれています。 もしあなたが優先順位に影響を及ぼしたければ、どうかライセンスかサポート登録して、 我々にあなたがより速く欲しいものを言ってください。 「3 MySQL ライセンスとサポート」節参照.

G.1 近い将来に完了せねばならないもの

• Fail safe replication.
• Optimize, test and document transactions safe tables
• 副問い合わせ。 select id from t where grp in (select grp from g where u > 100)
• mysqld に、同時に多くのキャラクタ・セットをサポートさせる
• もし他の disk に symlink されているテーブルに対して ALTER TABLE を 実行した場合、一時テーブルをこの disk に作成するようにする
• RENAME table as table, table as table [,...]
• FreeBSD and MIT-pthreads; Do sleeping threads take CPU?
• Check if locked threads take any CPU.
• キーの部分での JOIN を許す (最適化問題)
• Entry for DECRYPT().
• `.frm' ファイルに FOREIGN キーの定義を記憶する。
• サーバーサイドのカーソル
• 起動オプションの変更をユーザーに許すように
• Check if lockd works with modern Linux kernels; If not, we have to fix lockd! To test this, start mysqld with --enable-locking and run the different fork* test suits. They shouldn't give any errors if lockd works.
• Allow SQL variables in LIMIT, like in LIMIT @a,@b.
• 自動で DEFAULT 値をフィールドに追加しない。 DEFAULT を持たないフィールドを含まない INSERT の使用は エラーにする
• クエリーと結果のキャッシュ。 This should be done as a separated module that examines each query and if this is query is in the cache the cached result should be returned. When one updates a table one should remove as few queries as possible from the cache. This should give a big speed bost on machines with much RAM where queries are often repeated (like WWW applications). One idea would be to only cache queries of type: SELECT CACHED ....
• Fix `libmysql.c' to allow two mysql_query() commands in a row without reading results or give a nice error message when one does this.
• BIT 型を 1 bit 取るように最適化 （今 BIT は一文字とります）
• なぜいくつかの FreeBSD システムで MIT-pthreads ctime() が動かないか検証。
• Check if locked threads take any CPU.
• 更新に ORDER BY を追加。 This would be handy with functions like: generate_id(start,step).
• TIMESTAMP と AUTO_INCREMENT フィールドを更新しないように、 IMAGE オプションを LOAD DATA INFILE に追加。
• LOAD DATA INFILE に以下の文を理解させる：

  LOAD DATA INFILE 'file_name.txt' INTO TABLE tbl_name
  TEXT_FIELDS (text_field1, text_field2, text_field3)
  SET table_field1=concatenate(text_field1, text_field2), table_field3=23
  IGNORE text_field3
  

• 本当の VARCHAR のサポート (MyISAM にはこのサポートが既にあります)
• mysql から自動的に netscape に出力
• LOCK DATABASES. (いろいろなオプション付きで)
• NATURAL JOIN.
• Change sort to allocate memory in ``hunks'' to get better memory utilization.
• DECIMAL と NUMERIC 型は 指数表示の数字を読むことが出来ません： これを修正するには、 Field_decimal::store(const char *from,uint len) を再コードしなくてはなりません
• Fix mysql.cc to do fewer malloc() calls when hashing field names.
• 関数： ADD_TO_SET(value,set) と REMOVE_FROM_SET(value,set)
• t1 JOIN t2 ON ... と t1 JOIN t2 USING ... の使用の追加。 現在、 LEFT JOIN のみが使用できます。
• unsigned long long 型の完全なサポート。
• CASE 関数
• show status にもっと多くの変数を。 INSERT/DELETE/UPDATE 文のカウント。 レコードの読み込みと更新のカウント。 1テーブルでのSELECTとJOINを伴ったSELECTのカウント。 SELECT 中のテーブルの数のカウント。 キーバッファの reaad/write のヒット数(理論値と実数)のカウント。 ORDER BY, GROUP BY, 一時テーブルの作成のカウント
• もしクエリの途中で mysql を中断した場合、あなたは他から接続して 走っているクエリを kill しなくてはなりません。 最終的には、こういったことはサーバー内で検知されるように試みるべきです。
• テーブルの情報のためのハンドラーインターフェースの追加。 それをシステムテーブルとして使えるように。 これはもしあなたがすべてのテーブルについて情報をリクエストした場合は 少し遅くなるでしょう。 しかしとても柔軟性があります。 基本的なテーブルへの SHOW INFO FROM tbl_name では実行されるべきです。
• UNICODE のサポート
• NATURAL JOIN.
• Oracle like CONNECT BY PRIOR ... to search hierarchy structures.
• RENAME DATABASE
• mysqladmin copy database new-database.
• Processlist は queries/thread の数を表示すべき。
• IGNORE オプションを UPDATE 文に追加。 ( これは更新中に起こったキーの重複エラーのあるレコードを 全て削除するでしょう).
• Change the format of DATETIME to store fractions of seconds.
• ANSI92 と ODBC 3.0 型でかけている物全てを追加。
• Change table names from empty strings to NULL for calculated columns.
• Don't use 'Item_copy_string' on numerical values to avoid number->string->number conversion in case of: SELECT COUNT(*)*(id+0) FROM table_name GROUP BY id
• Make it possible to use the new GNU regexp library instead of the current one (The GNU library should be much faster than the old one).
• Change that ALTER TABLE doesn't abort clients that executes INSERT DELAYED.
• Allow select a from crash_me left join crash_me2 using (a); In this case a is assumed to come from the crash_me table.
• LOAD DATA INFILE 'file_name' INTO TABLE 'table_name' ERRORS TO err_table_name which would cause any errors/warnings to be logged into the err_table_name table. That table would have a structure like: line_number - line number in data file error_message - the error/warning message and maybe data_line - the line from the data file
• Fix that when columns referenced in an UPDATE clause contains the old values before the update started.
• Allow update of varibles in UPDATE statements. For example: UPDATE TABLE foo SET @a=a+b,a=@a, b=@a+c
• myisamchk, REPAIR and OPTIMIZE TABLE should be able to handle cases where the data and/or index files are symbolic links.

G.2 いつかは行うべきもの

• Implement function: get_changed_tables(timeout,table1,table2,...)
• Atomic updates; This includes a language that one can even use for a set of stored procedures.
• update items,month set items.price=month.price where items.id=month.id;
• Change reading through tables to use memmap when possible. Now only compressed tables use memmap.
• Add a new privilege 'Show_priv' for SHOW commands.
• Make the automatic timestamp code nicer. Add timestamps to the update log with SET TIMESTAMP=#;
• Use read/write mutex in some places to get more speed.
• Full foreign key support. One probably wants to implement a procedural language first.
• Simple views (first on one table, later on any expression).
• Automatically close some tables if a table, temporary table or temporary files gets error 23 (not enough open files).
• When one finds a field=#, change all occurrences of field to #. Now this is only done for some simple cases.
• Change all const expressions with calculated expressions if possible.
• Optimize key = expression. At the moment only key = field or key = constant are optimized.
• Join some of the copy functions for nicer code.
• Change `sql_yacc.yy' to an inline parser to reduce its size and get better error messages (5 days).
• Change the parser to use only one rule per different number of arguments in function.
• Use of full calculation names in the order part. (For ACCESS97)
• UNION, MINUS, INTERSECT and FULL OUTER JOIN. (Currently only LEFT OUTER JOIN is supported)
• Allow UNIQUE on fields that can be NULL.
• SQL_OPTION MAX_SELECT_TIME=# to put a time limit on a query.
• Make the update log to a database.
• Negative LIMIT to retrieve data from the end.
• Alarm around client connect/read/write functions.
• Make a mysqld version which isn't multithreaded (3-5 days).
• Please note the changes to safe_mysqld: according to FSSTND (which Debian tries to follow) PID files should go into `/var/run/<progname>.pid' and log files into `/var/log'. It would be nice if you could put the "DATADIR" in the first declaration of "pidfile" and "log", so the placement of these files can be changed with a single statement.
• Better dynamic record layout to avoid fragmentation.
• UPDATE SET blob=read_blob_from_file('my_gif') where id=1;
• Allow a client to request logging.
• Add use of zlib() for gzip-ed files to LOAD DATA INFILE.
• Fix sorting and grouping of BLOB columns (partly solved now).
• Stored procedures. This is currently not regarded to be very important as stored procedures are not very standardized yet. Another problem is that true stored procedures make it much harder for the optimizer and in many cases the result is slower than before We will, on the other hand, add a simple (atomic) update language that can be used to write loops and such in the MySQL server.
• Change to use semaphores when counting threads. One should first implement a semaphore library to MIT-pthreads.
• Don't assign a new AUTO_INCREMENT value when one sets a column to 0. Use NULL instead.
• Add full support for JOIN with parentheses.
• Reuse threads for systems with a lot of connections.
• As an alternative for one thread / connection manage a pool of threads to handle the queries.
• Allow one to get more than one lock with GET_LOCK. When doing this, one must also handle the possible deadlocks this change will introduce.

Time is given according to amount of work, not real time. TcX's main business is the use of MySQL not the development of it. But because TcX is a very flexible company, we have put a lot of resources into the development of MySQL.

G.3 行う予定のない物

• Nothing; In the long run we plan to be fully ANSI 92 / ANSI 99 compliant.

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