in 是把外表和内表作hash 连接,而exists是对外表作loop循环,每次loop循环再对内表进行查询。一直以来认为exists比in效率高的说法是不准确的。 not in 和 not exists 如果查询语句使用了not in 那么内外表都进行全表扫描,没有用到索引;而not extsts 的子查询依然能用到表上的索引。所以无论那个表大,用not ex...
Carol.Dean has ExtendedRight to 00299570-246d-11d0-a768-00aa006e0529 on [S-1-5-21-1540577040-1432127714-718651653-1143, CN=Jane.Ward,CN=Users,DC=pwn,DC=local] 我们可以通过远程MSRPC-SAMR协议修改Jane.Ward的密码,rpcclient默认支持hash认证: rpcclient -U "pwn\Carol.Dean" //10.0.1.100 --pw-...
Add Array Items to Listbox Add blank column to csv with no header? Add column to text file Add columns to PowerShell array and write the result to a table Add computer to AD group Add computers to domain in bulk / mass Add Computers to Security Group Based on OU Add current date ...
“Unable to enlist in the transaction” with Oracle linked server from MS SQL Server [<Name of Missing Index, sysname,>] in non clustered index [Execute SQL Task] Error: The value type (__ComObject) can only be converted to variables of type Object. [ODBC Driver Manager] Data source nam...
对于配置文件_jacg_config/o_g4caller_entry_method.properties中指定的方法,对每个方法生成一个对应的文件,文件名为“[类名]@[方法名]@[完整方法名 HASH+长度].txt”,示例为“TestClass1@func1@qDb0chxHzmPj1F26S7kzhw#048.txt”; 若某个方法生成向下的完整调用链时指定了代码行号范围,则对应文件名为“...
Indexes. They're one of the most powerful and misunderstood aspects of SQL performance. In this post we'll look at the purpose of an index, how to create and choose choose your index type. Then finish with a discussion of how to decide what to index and
Each row could be in a different location. Meaning you need ten I/O operations to read them all.This is bad news if you want the query to be as fast as possible. The more disk reads your SQL does, the slower it will be. Even if the rows are cached in memory, accessing ten ...
SQL Profiler captures activity occurring in SQL Server, driven by requests from your client application.The tool enables you to select precisely which events you want to monitor. For example, you might want to see when stored procedures are called, when they complete, how long they take to ...
其中关键一个数据结构是Log Directory,是一个无锁hash表,负责管理log records的location和当前PageStore上的Slices的页和版本的映射关系。key是page ID,value是相应page的一系列log的存储位置、各版本page的存储位置。该数据结构会被周期性的持久化。SAL侧做了throttle机制,LogDirectory在purge或log truncation阶段会被清...
mysql> CREATE TABLE th ( -> c1 INT, -> c2 VARCHAR(20) -> ) -> PARTITION BY HASH(c1) -> PARTITIONS 2; Query OK, 0 rows affected (0.00 sec) The partitions belonging to this table can be viewed using the query shown here: mysql> SELECT TABLE_NAME,PARTITION_NAME,TABLE_ROWS,AVG_...