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March 2010

March 25, 2010

Japanize の翻訳データ更新障害を解消しました

Japanize および Mylingual をご利用の方々、翻訳データを登録いただいている方々、いつもありがとうございます。

昨年末より、翻訳データの更新が一覧に反映されない、および、Japanize のプラグインを使っていて翻訳データを「定期的に更新」に設定している場合に更新が反映されない、という障害が発生しておりましたが、本日サーバを移転し、問題を解消いたしました (以前サーバを設置していた VPS 環境のメモリ制限による問題でした)。サーバ移転にともない、一時的な不具合が発生しているかもしれません。なにかお気づきのことがありましたら、しばらく時間をおいて再度お試しいただき、解消しないようであれば、こちらのエントリにコメント、あるいはメールでご連絡いただければと思います。


Q4M 0.9.3 prerelease (with support for "concurrent compaction")

Q4M (Queue for MySQL) periodically performs an operation called "compaction", which is sort of a garbage collection, that collects empty space from a queue file and returns to the OS.

The pitfall that exists until now was that during compaction, all operation on the queue table was being blocked.

My opinion was (is) that it is not a serious problem for most users, since the time required for compaction will be small in most cases (the time depends on the number (and size) of the rows alive on the queue table, and the number of the rows alive will be mostly small).

But for usecases where fast response is a requirement, I have added a "queue_use_concurrent_compaction" option to Q4M in the 0.9.3 prerelease.  When the variable is set to one in my.cnf, INSERTs will not be blocked during compaction.  Another configuration variable queue_concurrent_compaction_interval is also available to fine-tune response time of INSERTs during compaction.  The response of INSERTs during compaction will become faster as you set the variable smaller, although the compaction will become slower as a side effect.

# enable / disable concurrent compaction (0: disabled (default), 1: enabled)

# handle INSERTs for every N bytes of data is compacted (default: 1048576)

If you are already using Q4M without any problems, I recommend sticking to the version you are using, since the stability of Q4M might have degraded due to the introduction of the feature.

On the other hand if you were having problems with the issue or planning to use Q4M for a new application, I recommend using this release.  Have fun!  And if you find any problems, please send stacktraces to me :-)