The detail description as following:
"MySQL Database Error: Row size too large. The maximum row size
for the used table type, not counting BLOBs, is 8126. You have to
change some columns to TEXT or BLOBs "
main reasons as following:
1)MYSQL VARCHAR length limit is 65535 bytes,if you use UTF8,the
length limit is 65535/3.
2)mysql5.1 bug,the bug is http://bugs.mysql.com/bug.php?id=50495
please upgrade the MYSQL version to 5.1.47
OSC2011-Fukuoka に、日本MySQLユーザ会(MyNA)として参加してきました。OSC(オープンソースカンファレンス)は各地で開催されていますが、福岡は私にとって、地方*1OSC参加の原点でもあり、今年で5回目の参加になります。ちなみにOSC-Fukuoka
は、今年で５回目の開催だそうです。
http://www.ospn.jp/osc2011-fukuoka/
…
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在oracle中我们希望表的join方式按照顺序执行，需要加hint，一般是加ordering的关键字，在mysql中，也给出了这样的功能提示，那就是STRAIGHT_JOIN，example如下：
SELECT STRAIGHT_JOIN count(*)
FROM ext,rec
WHERE ext.guid=rec.guid
and ext.name like 'dddd%' and
rec.name not like 'dddd%'
JUGEMテーマ：コンピュータ
情報スキーマ(INFORMATION SCHEMA)はバージョン毎にテーブルが追加されていっています。MySQL 5.1で追加されたのは、次のものです。
[MySQL 5.1で追加された11個のテーブル] +---------------------------------------+ | Tables_in_information_schema | +---------------------------------------+ | ENGINES |独自: show engines相当の情報 | EVENTS |独自: イベントスケジューラのイベント情報(show events + α) | FILES |独自: NDB(MySQL Cluster)エンジンのディスクデータテーブル情報 | GLOBAL_STATUS |独自: show global status相当の情報 | GLOBAL_VARIABLES |独自: show global variables相当の情報 | PARTITIONS …[さらに読む]
Non-clustered:
The data is present in random order, but the logical ordering is
specified by the index. The data rows may be randomly spread
throughout the table. The non-clustered index tree contains the
index keys in sorted order, with the leaf level of the index
containing the pointer to the page and the row number in the data
page. In non-clustered index:
The physical order of the rows is not the same as the index
order.
Typically created on column used in JOIN, WHERE, and ORDER BY
clauses.
Good for tables whose values may be modified frequently.
Clustered:
Clustering alters the data block into a certain distinct order to
match the index, resulting in the row data being stored in order.
Therefore, only one clustered index can be created on a given
database table. Clustered indices can greatly increase overall
speed of retrieval, but usually only where the data is accessed
sequentially in …
MySQLでは5.0から情報スキーマをサポートしています。(バージョンにより利用できる情報に違いがあります) 情報スキーマはSQL標準(SQL/Information Schema)に定義されているもので、データベース上に定義されたオブジェクト(テーブル、ビュー、ストアドルーチンなど)のメタ情報(定義情報)を取得するものです。従来MySQLではSHOWコマンドという独自のコマンドでメタ情報を取得してきましたが、情報スキーマを利用することにより、以下の点が改善されます。
またMySQL …
TokuDB is a storage engine for MySQL that is specifically designed for high performance on write-intensive workloads.
It achieves this via Fractal Tree indexing, which is based on cache-oblivious algorithmic，TokuDB is a scalable, ACID and MVCC compliant storage engine that provides indexing-based query acceleration and supports online schema modifications
Fractal Tree indexes implement the same operations as a B-tree, and thus are a drop-in replacement for B-trees. The difference is in performance. Fractal Tree indexes effectively replace random I/O with sequential I/O, which is faster on spinning disks. By converting random I/O into sequential I/O, Fractal Trees index data at near disk bandwidth rates, regardless of the structure of the primary and secondary keys, and have range queries that stream data off disk at near disk bandwidth rates, even as the database grows. As a …
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