Author: mcbrown
Date: 2007-02-10 17:47:13 +0100 (Sat, 10 Feb 2007)
New Revision: 4888
Log:
Documenting Merge Engine conformance improvements (WL #3567)
Modified:
trunk/refman-4.1/storage-engines.xml
trunk/refman-5.0/se-merge.xml
trunk/refman-5.1/se-merge.xml
Modified: trunk/refman-4.1/storage-engines.xml
===================================================================
--- trunk/refman-4.1/storage-engines.xml 2007-02-10 04:33:53 UTC (rev 4887)
+++ trunk/refman-4.1/storage-engines.xml 2007-02-10 16:47:13 UTC (rev 4888)
Changed blocks: 1, Lines Added: 129, Lines Deleted: 0; 3935 bytes
@@ -1763,6 +1763,135 @@
</para>
<para>
+ In MySQL 4.1.23 and higher, when a table that is part of a
+ <literal>MERGE</literal> table is opened, the following checks are
+ applied before opening each table. If any table fails the
+ conformance checks, then the operation that triggered the opening
+ of the table will fail. The conformance checks applied to each
+ table are:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Table must have exactly the same amount of columns that
+ <literal>MERGE</literal> table has.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column order in the <literal>MERGE</literal> table must match
+ the column order in the underlying tables.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Additionally, the specification for each column in the parent
+ <literal>MERGE</literal> table and the underlying table are
+ compared. For each each column, MySQL checks:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Column type in the underlying table equals the column type
+ of <literal>MERGE</literal> table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column length in the underlying table equals the column
+ length of <literal>MERGE</literal> table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column of underlying table and column of
+ <literal>MERGE</literal> table can be
+ <literal>NULL</literal>.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ <listitem>
+ <para>
+ Underlying table must have at least the same amount of keys
+ that merge table has. The underlying table may have morekeys
+ than the <literal>MERGE</literal> table, but cannot have less.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ For each key:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Check if the key type of underlying table equals the key
+ type of merge table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if number of key parts (i.e. multiple columns within
+ a compound key) in the underlying table key definition
+ equals the number of key parts in merge table key
+ definition.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ For each key part:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Check if key part lengths are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part types are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part languages are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part can be <literal>NULL</literal>.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ </itemizedlist>
+
+ <para>
After creating the <literal>MERGE</literal> table, you can issue
queries that operate on the group of tables as a whole:
</para>
Modified: trunk/refman-5.0/se-merge.xml
===================================================================
--- trunk/refman-5.0/se-merge.xml 2007-02-10 04:33:53 UTC (rev 4887)
+++ trunk/refman-5.0/se-merge.xml 2007-02-10 16:47:13 UTC (rev 4888)
Changed blocks: 3, Lines Added: 154, Lines Deleted: 15; 6168 bytes
@@ -69,6 +69,16 @@
</para>
<para>
+ Starting with MySQL 5.0.36 the underlying table definitions and
+ indexes must conform more closely to the definition of the
+ <literal>MERGE</literal> table. Conformance will be checked when the
+ merged tables are opened, not when the <literal>MERGE</literal>
+ table is created. This means that changes to the definitions of
+ tables within a <literal>MERGE</literal> may cause a failure when
+ the <literal>MERGE</literal> table is accessed.
+ </para>
+
+ <para>
You can use <literal>SELECT</literal>, <literal>DELETE</literal>,
<literal>UPDATE</literal>, and <literal>INSERT</literal> on
<literal>MERGE</literal> tables. You must have
@@ -78,21 +88,22 @@
<literal>MERGE</literal> table.
</para>
- <para>
- <emphasis role="bold">Note</emphasis>: The use of
- <literal>MERGE</literal> tables entails the following security
- issue: If a user has access to <literal>MyISAM</literal> table
- <replaceable>t</replaceable>, that user can create a
- <literal>MERGE</literal> table <replaceable>m</replaceable> that
- accesses <replaceable>t</replaceable>. However, if the user's
- privileges on <replaceable>t</replaceable> are subsequently revoked,
- the user can continue to access <replaceable>t</replaceable> by
- doing so through <replaceable>m</replaceable>. If this behavior is
- undesirable, you can start the server with the new
- <option>--skip-merge</option> option to disable the
- <literal>MERGE</literal> storage engine. This option is available as
- of MySQL 5.0.24.
- </para>
+ <note>
+ <para>
+ The use of <literal>MERGE</literal> tables entails the following
+ security issue: If a user has access to <literal>MyISAM</literal>
+ table <replaceable>t</replaceable>, that user can create a
+ <literal>MERGE</literal> table <replaceable>m</replaceable> that
+ accesses <replaceable>t</replaceable>. However, if the user's
+ privileges on <replaceable>t</replaceable> are subsequently
+ revoked, the user can continue to access
+ <replaceable>t</replaceable> by doing so through
+ <replaceable>m</replaceable>. If this behavior is undesirable, you
+ can start the server with the new <option>--skip-merge</option>
+ option to disable the <literal>MERGE</literal> storage engine.
+ This option is available as of MySQL 5.0.24.
+ </para>
+ </note>
<para>
If you <literal>DROP</literal> the <literal>MERGE</literal> table,
@@ -154,6 +165,134 @@
</para>
<para>
+ In MySQL 5.0.36 and higher, when a table that is part of a
+ <literal>MERGE</literal> table is opened, the following checks are
+ applied before opening each table. If any table fails the
+ conformance checks, then the operation that triggered the opening of
+ the table will fail. The conformance checks applied to each table
+ are:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Table must have exactly the same amount of columns that
+ <literal>MERGE</literal> table has.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column order in the <literal>MERGE</literal> table must match
+ the column order in the underlying tables.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Additionally, the specification for each column in the parent
+ <literal>MERGE</literal> table and the underlying table are
+ compared. For each each column, MySQL checks:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Column type in the underlying table equals the column type
+ of <literal>MERGE</literal> table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column length in the underlying table equals the column
+ length of <literal>MERGE</literal> table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column of underlying table and column of
+ <literal>MERGE</literal> table can be
+ <literal>NULL</literal>.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ <listitem>
+ <para>
+ Underlying table must have at least the same amount of keys that
+ merge table has. The underlying table may have morekeys than the
+ <literal>MERGE</literal> table, but cannot have less.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ For each key:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Check if the key type of underlying table equals the key
+ type of merge table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if number of key parts (i.e. multiple columns within a
+ compound key) in the underlying table key definition equals
+ the number of key parts in merge table key definition.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ For each key part:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Check if key part lengths are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part types are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part languages are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part can be <literal>NULL</literal>.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ </itemizedlist>
+
+ <para>
After creating the <literal>MERGE</literal> table, you can issue
queries that operate on the group of tables as a whole:
</para>
Modified: trunk/refman-5.1/se-merge.xml
===================================================================
--- trunk/refman-5.1/se-merge.xml 2007-02-10 04:33:53 UTC (rev 4887)
+++ trunk/refman-5.1/se-merge.xml 2007-02-10 16:47:13 UTC (rev 4888)
Changed blocks: 1, Lines Added: 128, Lines Deleted: 0; 3680 bytes
@@ -147,6 +147,134 @@
</para>
<para>
+ In MySQL 5.1.15 and higher, when a table that is part of a
+ <literal>MERGE</literal> table is opened, the following checks are
+ applied before opening each table. If any table fails the
+ conformance checks, then the operation that triggered the opening of
+ the table will fail. The conformance checks applied to each table
+ are:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Table must have exactly the same amount of columns that
+ <literal>MERGE</literal> table has.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column order in the <literal>MERGE</literal> table must match
+ the column order in the underlying tables.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Additionally, the specification for each column in the parent
+ <literal>MERGE</literal> table and the underlying table are
+ compared. For each each column, MySQL checks:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Column type in the underlying table equals the column type
+ of <literal>MERGE</literal> table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column length in the underlying table equals the column
+ length of <literal>MERGE</literal> table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Column of underlying table and column of
+ <literal>MERGE</literal> table can be
+ <literal>NULL</literal>.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ <listitem>
+ <para>
+ Underlying table must have at least the same amount of keys that
+ merge table has. The underlying table may have morekeys than the
+ <literal>MERGE</literal> table, but cannot have less.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ For each key:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Check if the key type of underlying table equals the key
+ type of merge table.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if number of key parts (i.e. multiple columns within a
+ compound key) in the underlying table key definition equals
+ the number of key parts in merge table key definition.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ For each key part:
+ </para>
+
+ <itemizedlist>
+
+ <listitem>
+ <para>
+ Check if key part lengths are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part types are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part languages are equal.
+ </para>
+ </listitem>
+
+ <listitem>
+ <para>
+ Check if key part can be <literal>NULL</literal>.
+ </para>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ </itemizedlist>
+ </listitem>
+
+ </itemizedlist>
+
+ <para>
After creating the <literal>MERGE</literal> table, you can issue
queries that operate on the group of tables as a whole:
</para>
| Thread |
|---|
| • svn commit - mysqldoc@docsrva: r4888 - in trunk: refman-4.1 refman-5.0 refman-5.1 | mcbrown | 10 Feb |
