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转载 对电脑作如下设置
【桌面】→ 【右键】→ 【属性】→ 【外观】→ 【高级】→ 项目选择【窗口】→ 【颜色1（L）】→ 【选择（其它）】将色调改为：85。饱和度：123。亮度：205→添加到自定义颜色→在自定义颜色选定→确定
2012-03-13 10:59:02
607
原创 使用vs2019编译postgresql 12
1.按照PG的帮助下载需要的包，有一些不下到了，如xml的，但编译能通过，也许是12优化编译了，没存在的包能跳过了，具体原因再找2. git clone，速度慢的话，去网上找找，改hosts后，下载速度飞快。3.修改postgresql\src\tools\msvc\VSObjectFactory.pm中的DetermineVisualStudioVersion函数，直接返回retu...
2020-02-06 17:05:04
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原创 性能监控
vmstat 1 -SmSwap si: Amount of memory swapped in from disk (/s). so: Amount of memory swapped to disk (/s).CPU These are percentages of total CPU time. us: Time spent running n...
2018-03-13 19:56:26
548
原创 BenckMarkSQL5.0 绘图
yum install texinfo-texyum install libjpeg-turbo下载新版本的zlib http://www.zlib.net/./configure --prefix=/home/aaa/zlib1.2.6makemake installvi /etc/ld.so.conf.d/zlib.conf加入如下内容后保存退出/home/aaa/zlib1.2.6/li...
2018-03-13 14:11:18
398
原创 postgresql9.6中的 Row Security Policies
1.。中文VS2008下面编译pg9.6修改VSObjectFactory.pm 中的 DetermineVisualStudioVersion 直接 return '9.00';
2016-11-16 17:42:56
977
原创 HandlerSocket
HandlerSocket是mysql的一个插件,主要是越过parser,optimizer这一层,直接对数据库进行key/value的存储,对于大内存的数据库,能极大的提高性能. 通过阅读代码,发现它主要用到了mysql的下面的结构体struct tablevec_entry { TABLE *table; size_t refcount; bool modifie
2012-05-10 16:09:28
1228
原创 replication
这是pg的主从备份,就是有一个主机把修改发给一个或多个副机,pg主从机之间是通过log来实现的,而不是采用简单的SQL,主机是sender,从机是receiver,就是进程,有多少个receiver,主机就有多少个进程,默认是异步的,就是主机不停的从硬盘上log中读取,之后发给副机,副机把收到的log应用到数据库中,主机中正在执行的事务是与发送没关系的,目前还没有实现从内存的log buf
2012-05-02 23:41:38
1251
原创 postgresql 中的 large object
//主要有下面两个系统表,pg_largeobject_metadata主要记录权限的,有用的只有pg_largeobjectCATALOG(pg_largeobject_metadata,2995){ Oid lomowner; /* OID of the largeobject owner */#ifdef CATALOG_VARLEN /* variab
2012-05-02 23:41:08
2700
原创 dictionary
table 对应 column； index 对应 field /** Data structure for a column in a table */struct dict_col_struct{/*----------------------*//** The following are copied from dtype_t,so that all bit-
2012-04-21 00:02:52
920
原创 index
/** Data structure for a field in an index */struct dict_field_struct{ dict_col_t* col; /*!< pointer to the table column */ const char* name; /*!< name of the column */ unsigned prefix_len:1
2012-04-21 00:02:38
838
原创 buffer pool
/* IMPLEMENTATION OF THE BUFFER POOL =================================Performance improvement:------------------------Thread scheduling in NT may be so slow that the OS wait mechanism sh
2012-04-21 00:02:22
995
原创 innodb system table
//基本不下面几个系统表table = dict_mem_table_create("SYS_TABLES", DICT_HDR_SPACE, 8, 0); dict_mem_table_add_col(table, heap, "NAME", DATA_BINARY, 0, 0); dict_mem_table_add_col(table, heap, "ID", DATA_BI
2012-04-21 00:01:02
1122
原创 TABLESPACE MEMORY CACHE
/* IMPLEMENTATION OF THE TABLESPACE MEMORY CACHE =============================================The tablespace cache is responsible for providing fast read/write access totablespaces and log
2012-04-21 00:00:54
1106
原创 lock
/* An explicit record lock affects both the record and the gap before it.An implicit x-lock does not affect the gap, it only locks the indexrecord from read or update.If a transaction has modi
2012-04-21 00:00:46
1476
原创 asyn io
/** The asynchronous i/o array slot structure */typedef struct os_aio_slot_struct os_aio_slot_t;/** The asynchronous i/o array slot structure */struct os_aio_slot_struct{ ibool is_read; /*!
2012-04-21 00:00:36
1307
原创 memory pool
/*The main components of the memory consumption are:1. buffer pool,2. parsed and optimized SQL statements,3. data dictionary cache,4. log buffer,5. locks for each transaction,6. hash t
2012-04-20 23:59:56
837
原创 Binary Log
/***************************************************************************** MySQL Binary Log log_event.h This log consists of events. Each event has a fixed-length header, possibly
2012-04-20 23:59:49
1112
原创 Transaction
TransactionId 是一个32位的无符号整数,事务和子事务的id,全是按照一个顺序来的,当这个32位整数用完一圈后,就需要一些特殊的操作/*---------- * Check to see if it's safe to assign another XID. This protects against * catastrophic data loss due to X
2012-04-20 23:59:40
1441
原创 file space
/* SPACE HEADER ============File space header data structure: this data structure is contained in thefirst page of a space. The space for this header is reserved in every extentdescripto
2012-04-20 23:58:25
1171
原创 doublewrite buffer
http://www.mysqlperformanceblog.com/2006/08/04/innodb-double-write/ /** Doublewrite control struct */struct trx_doublewrite_struct{ mutex_t mutex; /*!< mutex protecting the first_free fiel
2012-04-20 23:58:17
1271
原创 rollback segment
/* Transaction rollback segment header *//*-------------------------------------------------------------*/#define TRX_RSEG_MAX_SIZE 0 /* Maximum allowed size for rollback segment in pages */#def
2012-04-20 23:58:07
1861
原创 purge
/** The control structure used in the purge operation */struct trx_purge_struct{ ulint state; /*!< Purge system state */ sess_t* sess; /*!< System session running the purge query */
2012-04-20 23:58:00
921
原创 INFORMATION SCHEMA table cache
这是系统视图的cache，看样子mysql没有用buffer pool，而是专门对系统视图做了一个cache每个表都有自已在内存中的cache, 最大为16M，分配时是按chunk进行的，初始大小是1024个行的大小，按照new = old + old/2这样的速度增加 /** Memory for each table in the intermediate buf
2012-04-20 23:57:50
986
原创 spin lock; rw lock
/*Our mutex implementation works as follows: After that we perform the atomictest-and-set instruction on the memory word. If the test returns zero, weknow we got the lock first. If the test retu
2012-04-20 23:57:18
1229
原创 master thread
mysql 中最重要的 daemon 线程，控制了大部分的后台工作 /** Types of threads existing in the system. */enum srv_thread_type { SRV_COM = 1, /**< threads serving communication and queries */ SRV_CONSOLE, /**< threa
2012-04-20 23:57:02
1177
原创 PHYSICAL RECORD
/* PHYSICAL RECORD (OLD STYLE) ===========================The physical record, which is the data type of all the recordsfound in index pages of the database, has the following format(low
2012-04-20 23:56:45
856
原创 read view
这就是多版本中在事务要读取元组时，进行判断的事务快照，和postgresql中的snapshot一样，就是名不一样，都是把事务启动时，还有运行的事务ID记录在一个列表里面，事务ID在这之间的还需要判断，比这区间小的认为是已提交的，比这区间大的认为是看不到的 /*多版本的限制FACT A: Cursor read view on a secondary index sees only
2012-04-20 23:56:30
1234
原创 log
/* Offsets of a log block header */#define LOG_BLOCK_HDR_NO 0 /* block number which must be > 0 and is allowed to wrap around at 2G; the highest bit is set to 1 if this is the firs
2012-04-20 23:56:17
571
原创 query graph
/* Query graph query thread node: the fields are protected by the kernelmutex with the exceptions named below */struct que_thr_struct{ que_common_t common; /*!< type: QUE_NODE_THR */ ulint mag
2012-04-20 23:55:39
1252
原创 Building Indexes Concurrently
/* * We do a concurrent index build by first inserting the catalog entry for the * index via index_create(), marking it not indisready and not indisvalid. * Then we commit our transaction and st
2012-04-20 23:54:48
600
原创 postgresql中增加系统参数
/* * Certain options can only be set at certain times. The rules are * like this: * * INTERNAL options cannot be set by the user at all, but only through * internal processes ("server_versio
2012-04-20 23:54:09
1296
原创 postgresql中的统计信息
pg里面有一个专门的进程 statistics collector 负责对数据库，表，函数的调用次数进行统计，通过socket与执行查询的进程进行通信，当执行语句的进程，在执行一条语句时，会在执行前，把上条语句的统计信息通过socket发送给 statistics collector 进程，这样做是因为上个事务已经 commit 或 rollback 了，统计的是事务已完成的数量。 sta
2012-04-20 23:54:01
3613
原创 postgresql中新增数据类型
在ADT目录下面新增一个文件,主要实现下面四个函数in : 输入函数,把SQL中的输入转化成数据库内部表示out: 输出函数,把数据库内部表示转化成可视的内容send recv 相当于二进制的 in ,out 在 include/catalog/pg_proc.h 中 增加那四个函数在 pg_proc的定义,这个pg_proc.h会生成BKI文件 include/c
2012-04-20 23:53:27
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原创 mysql的innodb启动过程
fil_init 主要是初始化文件打开指针哈希表，所有打开的文件全记录在 fil_system 之中，构造按名字查找的哈希表 buf_pool_init 内存缓冲池的初始化，对应 buf_pool_ptr 数组之中，还初始化了 adaptive hash index 的内存log_init 初始化log缓冲区，默认大小为 512*16k， 每个log页面大小为 #define OS_FIL
2012-04-20 23:53:02
1702
原创 btree
/*Latching strategy of the InnoDB B-tree--------------------------------------A tree latch protects all non-leaf nodes of the tree. Each node of a treealso has a latch of its own.A B-tree
2012-03-09 13:44:41
672
原创 windows和linux下面通用的线程程序
是从mysq里面抓好出来的，只抓了一部分，主要是线程间通信，是用windows模拟linux,方便多线程的开发
2011-04-29 17:23:00
1515
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