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mysql innodb存储与烦引的�ȝ��

happyenjoylife — Sat, 17 Dec 2011 08:36:00 GMT

Innodb存储

表空间是逻辑存放所有数据的地方�Q�默认情况下会共享一个表�I�间——ibdata1�Q�但如果�?/span>innodb_file_per_table=ON后每张表可以单独攑ֈ�一个表�I�间内，但还是有很多数据保存在共享的�?/span>ibdata1中，�?/span>undo信息�{��?/span>

表空间由各种�D?/span>(segment)�l�成�Q�常见的�D�|��数据�D�c��烦引段�{��?/span>Innodb是烦引组�l�的�Q�数据段��是clustered index的叶�l�点。需要注意的是，不是每个对象都有�D�c�?/span>

�?/span>(extend)是由64个连�l�的��늻�成，每个��（page�Q�固定�ؓ16KB�Q�所以每个区��d��?/span>1M。页�?/span>innodb最��的��盘��理单位�?/span>

Innodb是按行进行存攄��Q�每个区最��可以保�?/span>2条记录，否则��成铑ּ��l�构了。每行数据除了自定义列以外，�q�会增加事务id和回滚指针列。如果没有定�?/span>primary key也没�?/span>not null�?/span>unique,则会增加6字节�?/span>RowId列作��Z��键�?br />
囄��来自�Q?a >http://www.cnblogs.com/chjw8016/archive/2011/03/08/1976891.html

Innodb表的限制

一个表不能包含��过1000列�?/span>

内部最大键长度�?/span>3500字节�Q�但MySQL自己限制�q�个�?/span>1024字节�?/span>

除了VARCHAR, BLOB�?/span>TEXT列，最大行长度�E�微��于数据库页的一半。即�Q�最大行长度大约8000字节�?/span>LONGBLOB�?/span>LONGTEXT列必��d��?/span>4GB, �ȝ��行长度，��包�?/span>BLOB�?/span>TEXT列，必须��于4GB�?/span>InnoDB在行中存�?/span>VARCHAR�Q?/span>BLOB�?/span>TEXT列的�?/span>768字节�Q�余下的存储的分散的��中�?/span>

虽然InnoDB内部地支持行��寸大于65535�Q�你不能定义一个包�?/span>VARCHAR列的�Q�合�q�尺寸大�?/span>65535的行�?/span>

· mysql> CREATE TABLE t (a VARCHAR(8000), b VARCHAR(10000),

· -> c VARCHAR(10000), d VARCHAR(10000), e VARCHAR(10000),

· -> f VARCHAR(10000), g VARCHAR(10000));

· ERROR 1118 (42000): Row size too large. The maximum row size for the

· used table type, not counting BLOBs, is 65535. You have to change some

· columns to TEXT or BLOBs

在一些更老的操作�pȝ��上，数据文�g必须��于2GB�?/span>

InnoDB日志文�g的合�q�尺寸必��d��?/span>4GB�?/span>

最��的表空间尺寸是10MB。最大的表空间尺寸是4,000,000,000个数据库��（64TB�Q�。这也是一个表的最大尺寸�?/span>

InnoDB表不支持FULLTEXT索引

Innodb索引

默认情况�?/span>Memory使用存储hash索引�Q�但也支�?/span>b+tree索引�?/span>Hash索引只用�?/span>=或�?/span><=>的等式比较，不能用来加�?/span>order by操作�Q�只能通过关键字来搜烦一行�?/span>innodb只支�?/span>b+树烦引，�q�一步分�?/span>clustered index 与　secondary index。在一�ơ查询中�Q�只能��用一个烦引�?/span>

Innodb是烦引组�l�表�Q?/span>clustered index的叶�l�点保存着整行的数据。如果，定义�?/span>primary key�Q�则clustered index��是primary key的烦引；如果没有定义primary key mysql会选中�W�一个仅�?/span>not null列的unique索引作�ؓ主键�Q��ƈ把此索引当作clustered index使用�Q�如果没扑ֈ��q�样的列�Q?/span>innodb会创��Z��?/span>6字节�?/span>RowId作�ؓ主键。所以每张表有且只有一�?/span>clustered index�?/span>

Secondary index的叶�l�点不包括行的全部数据，包含键��g��外还包括一�?/span>bookmark�Q�可以告�?/span>innodb��C��么地方可以找到相对应的完整行数据�Q�还保存了主键的健倹{�?/span>Secondary index包含主键�Q�但不包含完整的行数据，所�?/span>innodb��L��会先�?/span>secondary index的叶节点判断是否能得到所需的数据。如,

Create table t(a int, b varchar(20), primary key(a), key(b));

Explain select * from t;

会发�?/span>mysql选择了烦�?/span>b�Q�而不�?/span>a.

复合索引

复合索引是在多列�Q?/span>>=2�Q�上建立的烦引，又叫多列索引或联合烦引�?/span>Innodb中的复合索引也是b+ tree�l�构。烦引的数据包含多列(col1, col2, col3…)�Q�在索引中依�ơ按�?/span>col1, col2, col3排序。如(1, 2), (1, 3),(2,0)…

使用复合索引要充分利用最左前�~�原则�Q�顾名思义�Q�就是最左优先。如创徏索引ind_col1_col2(col1, col2)�Q�那么在查询where col1 = xxx and col2 = xx或�?/span>where col1 = xxx都可以走ind_col1_col2索引�?/span>

在创建多列烦引时�Q�要�Ҏ��业务需求，where子句中��用最频繁且过滤效果好的的一列放在最左边�?/span>

索引操作

可以通过DML语句操作innodb索引。因�?/span>innodb是烦引组�l�的表，对烦引的操作会造成锁表�Q�先生成一张��时表�Q�将数据从原始表中写��C��时表�Q�再��原始表删除�Q�最后将临时表表名改为原始表表名�Q�因增加、删除、修改字�D�会对主索引产生影响�Q�所以也会锁表。对secondary index�?/span>Innodb plugin开始，支持快速烦引创建的�Ҏ��Q�在创徏的过�E�中不需要重��Q�所以速度会很快，同时引擎会在表上�?/span>S锁，在创��E�中只能�q�行��L��作�?/span>

索引设计原则

1. 搜烦的烦引列�Q�不一定是所要选择的列。也��是��_��最适合索引的列是出现在where子句中的列，或者连接子句中指定的列�Q�而不是出现在select关键字后的选择列表中的列�?/span>

2. 使用唯一索引。考虑某列的分布，索引的列的基数越大，索引的效果越好。例如，�Ҏ��别M/F列做索引没多大用处�?/span>

3. 使用短烦引。如果是对字�W�串�q�行索引�Q�如果有可能应该指定前缀长度�?/span>

4. 利用最左前�~�。尽量将使用频繁且过滤效果好的字�D�|��“左边”

5. 不要�q�度索引�?/span>

6. Innodb默认会按照一定的��序保存数据�Q�如果明��定义了主键�Q�则按照主键��序保存。如果没有主键，但有唯一索引�Q�就按照唯一索引的顺序保存。如果有几个列都是唯一的，都可以作��Z��键的时候，��Z��提高查询效率�Q�应选择最常用讉K��的列作�ؓ主键。另外，innodb�?/span>secondary index都会保存主键的键��|��所有主键要��可能选择较短的数据类型。可以看出，应当��量避免对主键的修改。经�q?/span>dba的测试，保证主键的递增可以提高插入性能�?/span>

Mysql如何使用索引

1. 对于创徏的多列烦引，只要查询的条件中用到了最左边的列�Q�烦引一般就会被使用�?/span>

2. 对于使用like的查询，后面如果是常量�ƈ且只�?/span>%号不在第一个字�W�，索引才可能被使用�?/span>

3. 如果对大文本�q�行搜烦�Q�应该��用全文烦引，而不是��?/span>like ‘%...%’. 但不�q�的�?/span>innodb不支持全文烦引�?/span>

4. 如果列名是烦引，使用 index_column is null��用烦引�?/span>Oracle是不行的�?/span>

5. 如果mysql估计使用索引比全表扫描更慢，最不会使用索引�?/span>

6. 如果使用memory/head表�ƈ�?/span>where条�g中不使用”=”�q�行索引列，那么不会用到索引�?/span>Head表只有在”=”的时候才会��用烦引�?/span>

7. �?/span>or分割开的条�Ӟ��如果or前的条�g中的列有索引�Q�而后面列中没有烦引，那么涉及到的索引都不会被用到�?/span>

8. 不是多列索引的第一部分不会走烦引�?/span>

9. �?/span>%开始的like不会走烦�?/span>

10. 如果列是字符�Ԍ��那么一定要�?/span>where条�g中把字符串常量值用引号引�v来，否则不能走烦引。因为，mysql默认把输入的帔R��D��行�{换以后才�q�行��索�?/span>

11. �l�过普通运��或函数�q�算后的索引字段不能使用索引

12. 不等于操作不能��用烦�Q?/span><>�?/span>not in�{?/span>

13. Order by 优化�Q�某些情况下�Q?/span>mysql可以使用一个烦引满��?/span>order by,而不需要额外的排序�?/span>Where条�g�?/span>order by 使用相同的烦引，�q�且order by的顺序和索引��序相同�Q��ƈ�?/span>order by的字�D�都是升序或者都是降序�?/span>

SELECT * FROM t1 ORDER BY key_part1,key_part2,... ;

SELECT * FROM t1 WHERE key_part1=1 ORDER BY key_part1 DESC, key_part2

DESC;

SELECT * FROM t1 ORDER BY key_part1 DESC, key_part2 DESC;

但是以下情况不��用烦引：

SELECT * FROM t1 ORDER BY key_part1 DESC, key_part2 ASC �Q?/span>

--order by 的字�D�|؜�?/span> ASC �?/span> DESC

SELECT * FROM t1 WHERE key2=constant ORDER BY key1 �Q?/span>

-- 用于查询行的关键字与 ORDER BY 中所使用的不相同

SELECT * FROM t1 ORDER BY key1, key2 �Q?/span>

-- 对不同的关键字��?/span> ORDER BY

可以使用explain查看sql的执行计划�?/span>

happyenjoylife 2011-12-17 16:36 发表评论

[转] Java bridge methods explained

happyenjoylife — Sat, 20 Aug 2011 02:19:00 GMT

原文�Q?

http://stas-blogspot.blogspot.com/2010/03/java-bridge-methods-explained.html

Bridge methods in Java are synthetic methods, which are necessary to implement some of Java language features. The best known samples are covariant return type and a case in generics when erasure of base method's arguments differs from the actual method being invoked.

Have a look at following example:

public class SampleOne {
public static class A<T> {
public T getT() {
return null;
}
}

public static class B extends A<String> {
public String getT() {
return null;
}
}
}

Which in reality is just an example of covariant return type and after erasure will look like following snippet:

public class SampleOne {
public static class A {
public Object getT() {
return null;
}
}

public static class B extends A {
public String getT() {
return null;
}
}
}

And after the compilation decompiled result class "B" will be following:

public class SampleOne$B extends SampleOne$A {
public SampleOne$B();

public java.lang.String getT();
Code:
0:   aconst_null
1:   areturn
public java.lang.Object getT();
Code:
0:   aload_0
1:   invokevirtual   #2; // Call to Method getT:()Ljava/lang/String;
4:   areturn
}

Above you can see there is new synthetic method "java.lang.Object getT()" which is not present in source code. That method acts as bridge method and all is does is delegating invocation to "java.lang.String getT()". Compiler has to do that, because in JVM method return type is part of method's signature, and creation of bridge method is the way to implement covariant return type.

Now have a look at following example which is generics-specific:

public class SampleTwo {
public static class A<T> {
public T getT(T args) {
return args;
}
}

public static class B extends A<String> {
public String getT(String args) {
return args;
}
}
}

after compilation class "B" will be transformed into following:

public class SampleThree$B extends SampleThree$A{
public SampleThree$B();

public java.lang.String getT(java.lang.String);
Code:
0:   aload_1
1:   areturn

public java.lang.Object getT(java.lang.Object);
Code:
0:   aload_0
1:   aload_1
2:   checkcast       #2; //class java/lang/String
5:   invokevirtual   #3; //Method getT:(Ljava/lang/String;)Ljava/lang/String;
8:   areturn
}

here, the bridge method, which overrides method from base class "A", not just calling one with string argument (#3), but also performs type cast to "java.lang.String" (#2). It means, that if you will execute following code, ignoring compiler's "unchecked" warning, the result will be ClassCastException thrown from the bridge method:

A a = new B();
a.getT(new Object()));

These two examples are the best known cases where bridge methods are used, but there is, at least, one more, where bridge method is used to "change" visibility of base class's methods. Have a look at following sample and try to guess where compiler may need the bridge method to be created:

package samplefour;

public class SampleFour {
static class A {
public void foo() {
}
}
public static class C extends A {

}
public static class D extends A {
public void foo() {
}
}
}

If you will decompile class C, you will see method "foo" there, which overrides method from base class and delegates to it:

public class SampleFour$C extends SampleFour$A{

public void foo();
Code:
0:   aload_0
1:   invokespecial   #2; //Method SampleFour$A.foo:()V
4:   return

}

compiler needs that method, because class A is not public and can't be accessed outside it's package, but class C is public and all inherited method have to become visible outside the package as well. Note, that class D will not have bridge method, because it overrides "foo" and there is no need to "increase" visibility.
It looks like, that type of bridge method, was introduced after bug which was fixed in Java 6. It means that before Java 6 that type of bridge method is not generated and method "C#foo" can't be called from package other than it's own via reflection, so following snippet causes IllegalAccessException, in cases when compiled on Java version < 1.6:

package samplefive;

SampleFour.C.class.getMethod("foo").invoke(new SampleFour.C());

Normal invocation, without using reflection, will work fine.

Probably there are some other cases where bridge methods are used, but there is no source of information about it. Also, there is no definition of bridge method, although you can guess it easily, it's pretty obvious from examples above, but still would be nice to have something in spec which states it clearly. In spite of the fact that method Method#isBridge() is part of public reflection API since Java1.5 and bridge flag is part of class file format, JVM and JLS specifications do not have any information what exactly is that and do not provide any rules when and how it should be used by compiler. All I could find is just reference in "Discussion" area here.

happyenjoylife 2011-08-20 10:19 发表评论

happyenjoylife — Fri, 27 May 2011 06:39:00 GMT

异常�?/span>

每一�?/span>try语句�?/span>catch的异帔R��与异常表中的一��相对应�Q�异常表中的每一��w��包括�Q?/span>

��L��
�l�点�Q�始�l�把catch异常位置�?/span>pc指针偏移量的最大值大�Q?/span>
处理异常时蟩转到的字节码序列中的pc指针偏移�?/span>
�?/span>catch的异常类的常量池索引

例如�Q?/p>

public class Test {
    public static void main(String[] args) {

        try {
            Class.forName("java.lang.String");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }

    }
}

�?/span>javap –c查看字节码如下：

Compiled from "Test.java"
public class Test extends java.lang.Object{
public Test();
  Code:
   0:    aload_0
   1:    invokespecial    #1; //Method java/lang/Object."":()V
   4:    return

public static void main(java.lang.String[]);
  Code:
   0:    ldc    #2; //String java.lang.String
   2:    invokestatic    #3; //Method java/lang/Class.forName:(Ljava/lang/String;)Ljava/lang/Class;
   5:    pop
   6:    goto    14
   9:    astore_1
   10:    aload_1
   11:    invokevirtual    #5; //Method java/lang/ClassNotFoundException.printStackTrace:()V
   14:    return
  Exception table:
   from   to  target type
     0     6     9   Class java/lang/ClassNotFoundException
}

可见ClassNotFoundException异常可能会在0~6之间抛出�Q?/span>9开始处的代码处理此异常�?/span>

当��生异常的时候，jvm��会在整个异常表中搜索与之匹配的��，如果当前pc在异常表入口所指的范围内，�q�且所抛出的异常是此入口所指向的类或者其子类�Q�则跌��{到对应的处理代码�l�箋执行�?/span>

�Ҏ��可能会抛出哪些已��查异�?/span>

Class文�g�?/span>attribute_info中保存有Exceptions属性，记录着每个�Ҏ��throws的异�怿�息。具体的可以查看class�c�L��件格式相关的文章�?/span>

athrow指��o从栈��弹�?/span>Throwable对象引用�Q�抛出异常�?/span>

finally语句

�?/span>jvm规范中，finally语句是通过jsr/jsr_w�?/span>ret指��o实现的。当执行jsr/jsr_w的时候将finally执行完成后的�q�回地址压入栈中�Q�进�?/span>finally后会马上��此地址保存��C��个局部变量中�Q�执行完成后�Q?/span>ret从此局部变量中取出�q�回地址。？�Q�？��Z��么会先把�q�回地址保存到局部变量中呢？�Q�？因�ؓ�Q�当�?/span>finally语句�q�回的时候需要将�q�回地址成栈中弹出，�?/span>finally语句非正常结�?/span>(break,continue,return, 抛异�?/span>)的时候就不用再考虑�q�个问题�?/span>

以下�?/span>jvm规范�?/span>Compiling finally的一�D�：

void tryFinally() {
    try {
        tryItOut();
    } finally {
        wrapItUp();
    }
}
the compiled code is
Method void tryFinally()
   0     aload_0            // Beginning of try block
   1    invokevirtual #6         // Method Example.tryItOut()V
   4     jsr 14            // Call finally block
   7     return            // End of try block
   8     astore_1            // Beginning of handler for any throw
   9     jsr 14            // Call finally block
  12     aload_1            // Push thrown value
  13     athrow            // and rethrow the value to the invoker
  14     astore_2            // Beginning of finally block
  15     aload_0            // Push this
  16     invokevirtual #5         // Method Example.wrapItUp()V
  19     ret 2            // Return from finally block
Exception table:
       From     To     Target         Type
    0        4        8           any

�?/span>tryItOut排除��M��异常后都��会被异常表中的any��Ҏ��P��执行�?/span>finally后，会执�?/span>athrow指��o��异常抛出�?/span>

�?/span>jdk的某一个版本开始就不会�~�译出编译出�?/span>jsr/jsr_w�?/span>ret的字节码了，因�ؓ有指令上的缺��P��D��jvm的检验和分析�pȝ��出现漏洞�?/span>

再说finally的非正常退�?/span>

�?/span>finally中��?/span>break�?/span>continue�?/span>return、抛出异常等认�ؓ�?/span>finally的非正常�l�束。非正常�l�束的时候，ret指��o不会被执行，很可能会出现意想不到的结果。如�Q?/span>

public class Test {
    public static boolean test(boolean b) {
        while (b) {
            try {
                return true;
            } finally {
                /*
                break;                          始终�q�回false
                continue;                         javac�~�译再java执行会出现死循环
                                                在eclipse中甚至会出现报错�Q�提�C�找��C��main class
                return false;                     始终�q�回false
                throw new RuntimeException("");    抛出异常
                 */
            }
        }

        return false;
    }

    public static void main(String[] args) {
        System.out.println(test(true));
    }
}

��Q�在�?/span>finally语句的时候，��量避免非正常结束！

happyenjoylife 2011-05-27 14:39 发表评论

分库分表�ȝ��

happyenjoylife — Fri, 13 May 2011 07:31:00 GMT

单库单表

单库单表是最常见的数据库设计�Q�例如，有一张用�?span lang="EN-US">(user)表放在数据库db中，所有的用户都可以在db库中�?span lang="EN-US">user表中查到�?/p>

单库多表

随着用户数量的增加，user表的数据量会��来��大�Q�当数据量达��C��定程度的时候对user表的查询会渐渐的变慢�Q�从而媄响整�?span lang="EN-US">DB的性能。如果��?span lang="EN-US">mysql, �q�有一个更严重的问题是�Q�当需要添加一列的时候，mysql会锁表，期间所有的��d��操作只能�{�待�?/p>

可以通过某种方式��?span lang="EN-US">user�q�行水��^的切分，产生两个表结构完全一��L��user_0000,user_0001�{�表�Q?span lang="EN-US">user_0000 + user_0001 + …的数据刚好是一份完整的数据�?/p>

多库多表

随着数据量增加也许单�?span lang="EN-US">DB的存储空间不够，随着查询量的增加单台数据库服务器已经没办法支撑。这个时候可以再�Ҏ��据库�q�行水��^区分�?/p>

分库分表规则

设计表的时候需要确定此表按照什么样的规则进行分库分表。例如，当有新用��h��Q�程序得��定��此用户信息��d��到哪个表中；同理�Q�当��d��的时候我们得通过用户的�̎��h��到数据库中对应的记录�Q�所有的�q�些都需要按照某一规则�q�行�?/p>

路由

通过分库分表规则查找到对应的表和库的�q�程。如分库分表的规则是user_id mod 4的方式，当用��h��注册了一个�̎��P��账号id�?span lang="EN-US">123,我们可以通过id mod 4的方式确定此账号应该保存�?span lang="EN-US">User_0003表中。当用户123��d��的时候，我们通过123 mod 4后确定记录在User_0003中�?/p>

分库分表产生的问题，及注意事��?/h2>
1. 分库分表�l�度的问�?/p>
假如用户购买了商�?span lang="EN-US">,需要将交易记录保存取来�Q�如果按照用��L��U�度分表�Q�则每个用户的交易记录都保存在同一表中�Q�所以很快很方便的查扑ֈ�某用��L��购买情况�Q�但是某商品被购买的情况则很有可能分布在多张表中�Q�查找�v来比较麻烦。反之，按照商品�l�度分表�Q�可以很方便的查扑ֈ�此商品的购买情况�Q�但要查扑ֈ��C�h的交易记录比较麻烦�?/p>

所以常见的解决方式有：

   a.通过扫表的方式解冻I��此方法基本不可能�Q�效率太低了�?/p>
   b.记录两䆾数据�Q�一份按照用��L��度分表，一份按照商品维度分表�?/p>
   c.通过搜烦引擎解决�Q�但如果实时性要求很高，又得关系到实时搜索�?/p>

2. 联合查询的问�?/p>
联合查询基本不可能，因�ؓ兌��的表有可能不在同一数据库中�?/p>

3.   避免跨库事务

避免在一个事务中修改db0中的表的时候同时修�?span lang="EN-US">db1中的表，一个是操作��h��更复杂，效率也会有一定媄响�?/p>

4. ��量把同一�l�数据放到同一DB服务器上

例如��卖�?span lang="EN-US">a的商品和交易信息都放�?span lang="EN-US">db0中，�?span lang="EN-US">db1挂了的时候，卖家a相关的东西可以正�怋�用。也��是说避免数据库中的数据依赖另一数据库中的数据�?/p>

一��d��?/h2>
在实际的应用中，�l�大部分情况都是读远大于写�?span lang="EN-US">Mysql提供了读写分��ȝ��机制�Q�所有的写操作都必须对应�?span lang="EN-US">Master�Q�读操作可以�?span lang="EN-US">Master�?span lang="EN-US">Slave机器上进行，Slave�?span lang="EN-US">Master的结构完全一��P��一�?span lang="EN-US">Master可以有多�?span lang="EN-US">Slave,甚至Slave下还可以�?span lang="EN-US">Slave,通过此方式可以有效的提高DB集群�?span lang="EN-US">QPS.

所有的写操作都是先�?span lang="EN-US">Master上操作，然后同步更新�?span lang="EN-US">Slave上，所以从Master同步�?span lang="EN-US">Slave机器有一定的延迟�Q�当�pȝ��很繁忙的时候，延迟问题会更加严重，Slave机器数量的增加也会�ɘq�个问题更加严重�?/p>
此外�Q�可以看�?span lang="EN-US">Master是集��的瓉��Q�当写操作过多，会严重媄响到Master的稳定性，如果Master挂掉�Q�整个集��都��不能正常工作�?/p>
所以，1. 当读压力很大的时候，可以考虑��d��Slave机器的分式解冻I��但是�?span lang="EN-US">Slave机器辑ֈ�一定的数量��得考虑分库了�?span lang="EN-US"> 2. 当写压力很大的时候，��必��d��q�行分库操作�?/p>

另外�Q�可能会因�ؓ�U�种原因�Q�集��中的数据库��g配置�{�会不一��P��某些性能高，某些性能低，�q�个时候可以通过�E�序控制每台机器��d��的比重，辑ֈ�负蝲均衡�?/p>

备䆾地址�Q?span style="font-family: Simsun; line-height: normal; font-size: medium; ">http://happyenjoylife.iteye.com/admin/blogs/1042538

happyenjoylife 2011-05-13 15:31 发表评论

happyenjoylife — Mon, 03 Jan 2011 12:21:00 GMT

XP下试�q�，保存��h��怕将来忘�?

HKeyCurrentUser"SOFTWARE"Microsoft"Windows"CurrentVersion"Internet Settings
增加�Q?br /> DnsCacheEnabled 0x0 (REG_DWORD)
DnsCacheTimeout 0x0 (REG_DWORD)
ServerInfoTimeOut 0x0 (REG_DWORD)

happyenjoylife 2011-01-03 20:21 发表评论

happyenjoylife — Mon, 03 Jan 2011 11:46:00 GMT

1. 安装mercurial

Mercurial是一个版本管理工兗��?/span>

sudo apt-get install mercurial

安装mercurial的扩展，��d��fclone在支�?/span>

hg clone http://bitbucket.org/pmezard/hgforest-crew

��以下内�Ҏ��加到$HOME/.hgrc文�g中，如果没有则自己创��Z��个：

[extensions]

forest=/home/daren/hgforest-crew/forest.py

fetch=

2. 下蝲jdk7源码

hg fclone http://hg.openjdk.java.net/jdk7/jdk7

3. 安装gcc�?/span>g++�?/span>make�{?/span>

sudo apt-get install build-essential

4. 安装XRender

sudo apt-get install libxrender-dev

sudo apt-get install xorg-dev

5. 安装alsa

sudo apt-get install libasound2-dev

6. Cups

sudo apt-get install libcups2-dev

7. 安装jdk6

8. 安装ant

讄��ANT_HOME

9. 安装findbugs

�~�译需要这玩意儿有点奇怪。需要设�|?/span>FINDBUGS_HOME

10. ��试�~�译

export LANG=C ALT_BOOTDIR=/opt/jdk1.6.0_22/

#删除JAVA_HOME

export -n JAVA_HOME

export ALT_JDK_IMPORT_PATH=/opt/jdk1.6.0_22/

make sanity BUILD_JAXWS=false BUILD_JAXP =false

�?/span>build BUILD_JAXWS�?/span>BUILD_JAXP��L��提示找不到源文�g�Q�而我又暂时对只对JDK�?/span>Hotspot感兴��，所以烦性把�q�两个给��L��?/span>

如果出现:Sanity check passed.则表�C�测试编译通过了，不过也别开心得太早�Q�真�?/span>make的时候不保证一定没问题�Q�也许还会缺��某些依赖�?/span>

11. �~�译