m2m connections

Discussion socket must discuss long and short connectionsConcept of one, long connection and short connection1, the concept of long connection and short connection: The former is the entire communication process, the client and server only with a socket object, long-term to maintain the connection of the socket; the latter is a new socket for each request, which closes the socket directly after processing a request. So, in fact, the difference between the length of the connection is: the entire

Connections in SQL can be divided into inner joins, outer joins, and cross connections.1. Cross JoinWithout a WHERE clause, it will return the Cartesian product of the two tables connected, and the number of rows returning the result is equal to the product of two table rows;For example, the following results are the same for a, B, and C, but are not as efficient:A:select * FROM table1 cross JOIN table2B:se

1.Linux Link ConceptThere are two kinds of Linux links, one is called hard link (Hard link), the other is called Symbolic link (symbolic link). By default, the LN command produces a hard link. "Hard Connection"A hard connection refers to a connection through an index node. In a Linux file system, a file stored in a disk partition is assigned a number, called an index node number (Inode index), regardless of its type. In Linux, multiple file names point to the same index node. Generally this con

Difference Knowledge Points: 1, the definition and use of various connections Internal connections: Equal connection, non-equal connection (often not spoken) Natural connection, you find the same field, do not have to give two tables between the columns to compare. So-called nature (not commonly used) Cross connection, after selection, the product of the Cartesian card. This is useful if you want to list al

Viewed the number of connections and the current number of connections Copy Code code as follows: Netstat-ant | grep $IP: 80 | Wc-l Netstat-ant | grep $IP: 80 | grep EST | Wc-l View IP access times Copy Code code as follows: Netstat-nat|grep ":" |awk ' {print $} ' |awk-f: ' {print $} ' | Sort| Uniq-c|sort-n Linux command: Copy Code code as follows:

**********************************/ As CURSOR C_kill_sqls Is SELECT ' alter system kill session ' | | s.sid| | ', ' | | s.serial#| | ' immediate ' SQLSTR from v$session s WHERE s.status= ' sniped '; BEGIN For V_sql in C_kill_sqls LOOP EXECUTE IMMEDIATE V_sql.sqlstr; END LOOP; END; --add job to periodically clean out expired sessions DECLARE jobnum Number: = 661;

ArticleDirectory Maximum number of TCP connections per single IP Address Maximum number of TCP connections per single IP Address Category: TCP/IP In a TCP application, the server listens on a fixed port in advance, the client initiates a connection, and establishes a TCP connection after three handshakes. What is the maximum number of concurrent TCP

1, modify the user process can open the number of files limitOn a Linux platform, regardless of whether you write a client or a service-side program, the highest concurrency is limited by the number of files that can be opened by the system at the same time as the user's single process (because the system creates a socket handle for each TCP connection) for high concurrent TCP connection processing. Each socket handle is also a file handle. You can use the Ulimit command to view the limit on the

The number of concurrent connections refers to the ability of the firewall or proxy server to process the business information flow. It is the maximum number of point-to-point connections that the firewall can simultaneously process, it reflects the access control and connection status tracking capabilities of firewall devices for multiple connections. The size o

We are already in the process of making n + connections and the number of simultaneous builds has bee, simultaneous Simultaneous-build-throttle:This is the maximum number of connections we can be building at any one time.That is, the number of new connections that have been requested but aren't yet available for use.Because c