1-1 检查连接的脚本：/introduction/check_connection.py from redis import Redis client = Redis() # ping() ⽅法在连接正常时将返回 True if client.ping() is True: print("connecting") else: print("disconnected") __init__(self, client): self.client = client def set(self, key, value): """ 把需要被缓存的数据储存到键 key ⾥⾯， 如果键 key 已经有值，那么使⽤新值去覆盖旧值。 """ self.client.set(key, """ 获取储存在键 key ⾥⾯的缓存数据， 如果数据不存在，那么返回 None 。 """ return self.client.get(key) def update(self, key, new_value): """ 对键 key 储存的缓存数据进⾏更新，

PropertyFileSnitch 19 EC2Snitch 19 EC2MultiRegionSnitch 19 About Dynamic Snitching 19 About Client Requests in Cassandra 19 About Write Requests 20 About Multi-Data Center Write Requests 20 About Consistency for Client Requests 58 About Write Consistency 58 About Read Consistency 58 Choosing Client Consistency Levels 59 Consistency Levels for Multi-Data Center Clusters 59 Specifying Client Consistency Features 60 Cassandra Client APIs 60 About Cassandra CLI 60 About CQL 61 Other High-Level Clients 61 Java: Hector Client API 61 Python: Pycassa Client API 61 PHP: Phpcassa Client API 61 Getting Started

SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE, NULL); zumero_register(db); Alternatively, the Zumero client library may have been provided as a dynamically loadable extension: SELECT load_extension('zumero a SQLite database file, one on the client, and the other on the server. We can refer to these two copies as two instances of the same SQLite database. On the client, all of your interaction with the SQLite which one is which, each one is given a unique name. Unlike the filesystem abstraction presented on a client, the server's abstraction is a flat list, not a hierarchy. The Zumero server is very particular

Jaybird (Firebird JDBC driver). The protocol is described in the form of the message sent by the client and received from the server. The described protocol is Firebird/Interbase protocol version 10. vector, information request items, and the meaning of operations. Unless otherwise indicated, a client request must be flushed to the server for processing. For some operations the flush can be deferred attachment to a database. 3.1.1. Identification Performs the initial handshake and protocol selection. Client Int32 Operation code (op_connect) Int32 Operation code (op_attach) Int32 Version (CONNECT_VERSION2)

MPP 架构，适⽤于海量数据的存储和计算。UDW 的架构如上图所⽰，主要有 Client、Master Node 和 Compute Node 组成。基本组成部分的功能如下： 产品架构 Greenplum数据仓库 UDW Copyright © 2012-2021 UCloud 优刻得 7/206 1. Client：访问 UDW 的客⼾端 ⽀持通过 JDBC、ODBC、PHP、Python、命令⾏ com/greenplum-client.tar tar -zxvf greenplum-client.tar.gz 2）配置udw客⼾端 进⼊ greenplum-client 安装⽬录，编辑 greenplum_client_path.sh 修改UDW_HOME(export UDW_HOME= client安装⽬录)（如/root/greenplum-client） 3） 使配置⽣效 在~/ 在~/.bashrc中添加如下配置 source /data/greenplum-client/greenplum\_client\_path.sh 执⾏ source ~/.bashrc 备注：/data/greenplum-client是greenplum-client的安装路径 4） 连接数据库 psql -h hostIP（或域名） –U username -d database

standalone tool (vtctl) and client- server (vtctlclient in combination with vtctld). Using client-server is recommended, as it provides an additional layer of security when using the client remotely. Using vtctl that routes traffic to the correct VTTablet servers and returns consolidated results back to the client. It speaks both the MySQL Protocol and the Vitess gRPC protocol. Thus, your applications can connect sudo apt-get install -y mysql-server mysql-client make unzip g++ etcd curl git wget # Debian sudo apt-get install -y default -mysql-server default -mysql-client make unzip g++ etcd curl wget 21 The services

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 371 Client authentication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 381 Generating client certificates with easy-rsa . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . are handled by Vitess and how they are handled. System variable Handled autocommit VitessAware client_found_rows VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only

running . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10 3.5. Performing a client-only install . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 32 Table of Contents 1 6.2.2. Connecting with a GUI client . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . additional process for each client connection. Using a locking mechanism, it allows shared connections to database files. • SuperClassic (ThreadedShared) is a single server process. Client connections are handled

Connection Protocol with XNet .................................................................... 10 Client Impersonation No Longer Works .................................................................. ............................................................................................ 28 Client-only Installs .................................................................................. the end of the result set Important In former versions, NULLs were always at the end. If you have client code or PSQL definitions that rely on the legacy NULLs placement, it will be necessary to use the

are handled by Vitess and how they are handled. System variable Handled autocommit VitessAware client_found_rows VitessAware skip_query_plan_cache VitessAware tx_read_only VitessAware transaction_read_only mit ReservedConn binlog_format CheckAndIgnore block_encryption_mode CheckAndIgnore character_set_client CheckAndIgnore character_set_connection CheckAndIgnore character_set_database CheckAndIgnore cha standalone tool (vtctl) and client- server (vtctlclient in combination with vtctld). Using client-server is recommended, as it provides an additional layer of security when using the client remotely. Using vtctl