Sizesize);/* call this free_p in case someone #define's free() */void(*free_p)(MemoryContextcontext,void*pointer);void*(*realloc)(MemoryContextcontext,void*pointer,Sizesize);void(*reset)(MemoryContextcontext);void(*delete_context)(MemoryContextcontext);Size(*get_chunk_...
1. In-Memory Hash Join Cost(HJ)=Read(S)+ build hash table in memory(CPU)+Read(B) + Perform In memory Join(CPU) 忽略cpu的时间,则 Cost(HJ)=Read(S)+Read(B) 2. On-Disk Hash Join 根据上述的步骤描述,我们可以看出 Cost(HJ)=Cost(HJ1)+Cost(HJ2) 其中Cost(HJ1)的成本就是扫描S,B表...
要使用大页面，需要为运行PostgreSQL的Windows用户账号分配Lock Pages in Memory的用户权限。可以使用Windows的组策略工具（gpedit.msc）来分配用户权限Lock Pages in Memory。为了在命令窗口以单进程（而不是Windows服务）的方式启动数据库服务器，命令窗口必须以管理员身份运行或者禁用用户访问控制（UAC）。当UAC被启用时...
Local Memory Area Each backend process allocates a local memory area for query processing; each area is divided into several sub-areas – whose sizes are either fixed or variable. Table 2.2 shows a list of the major sub-areas. The details will be described in the following chapters. sub-ar...
Out-of-Line, In-Memory TOAST Storage TOAST指针可以指向当前服务进程所占用的内存,这种指针不能够长期存在,并且主要应用到以下两个场景中:指向间接数据与扩展数据。 间接指针单纯地指向内存中长度可变的数据,并用于避免不得不创建超过1GB的元组的情况。
In-memory columnar storage engine; On-disk row-oriented storage engine with undo-logforbetter bloat control. 行式内存引擎、列式内存引擎、列存磁盘存储引擎、以及回滚段模式的行式磁盘存储引擎。 目前还没有看到代码方面的输出,但是在postgrespro的项目里有一个与内存表非常类似的项目,会话级变量。
typedefstructAllocSetContext{MemoryContextData header;/*对应于该内存上下文的头部信息 Standard memory-context fields *//* Info about storage allocated in this context: */AllocBlock blocks;/*该内存上下文中所有内存块的链表 head of list of blocks in this set */AllocChunk freelist[ALLOCSET_NUM_FREELI...
CacheMemoryContext: 524288 total in 7 blocks; 104920 free (0 chunks); 419368 used index info: 2048 total in 2 blocks; 824 free (0 chunks); 1224 used index info: 2048 total in 2 blocks; 496 free (1 chunks); 1552 used index info: 3072 total in 2 blocks; 1160 free (2 chunks); ...
What are the differences in clustering between PostgreSQL and SQL Server? Compare clustering in PostgreSQL vs. MSSQL 中文:服务器实例的比较 PostgreSQL PostgreSQL允许服务器集群,但不支持本地多主或主-主的集群。例如repmgr等工具可以轻松维护PostgreSQL集群。
*/ tbm_bitmapword words[Max(WORDS_PER_PAGE, WORDS_PER_CHUNK)];} PagetableEntry;struct TIDBitmap{ NodeTag type; /* to make it a valid Node */ MemoryContext mcxt; /* memory context containing me */ TBMStatus status; /* see codes above */ struct page...