MySQL 8.4 Release Notes
ndb_select_count 打印一个或多个 NDB 表中的行数。对于单个表，结果等同于使用 MySQL 语句 SELECT COUNT(*) FROM
tbl_name 所得到的结果。ndb_select_count prints the number of rows in
one or more NDB tables. With a
single table, the result is equivalent to that obtained by using
the MySQL statement SELECT COUNT(*) FROM
.tbl_name
使用方法Usage
ndb_select_count [-cconnection_string] -ddb_nametbl_name[,tbl_name2[, ...]]
可以与ndb_select_count一起使用的选项显示在下表中。表格之后有更多描述。Options that can be used with ndb_select_count are shown in the following table. Additional descriptions follow the table.
命令行格式Command-Line Format --character-sets-dir=path--character-sets-dir=path包含字符集的目录。Directory containing character sets.
命令行格式Command-Line Format --connect-retries=#类型Type 整数Integer 默认值Default Value 12最小值Minimum Value 0最大值Maximum Value 12放弃之前重试连接的次数。Number of times to retry connection before giving up.
命令行格式Command-Line Format --connect-retry-delay=#类型Type 整数Integer 默认值Default Value 5最小值Minimum Value 0最大值Maximum Value 5尝试联系管理服务器之间等待的秒数。Number of seconds to wait between attempts to contact management server.
命令行格式Command-Line Format --connect-string=connection_string类型Type 字符串String 默认值Default Value [none][none]同
--ndb-connectstring。Same as--ndb-connectstring.命令行格式Command-Line Format --core-file错误时生成核心文件；用于调试。Write core file on error; used in debugging.
命令行格式Command-Line Format --defaults-file=path类型Type 字符串String 默认值Default Value [none][none]仅从指定文件读取默认选项。Read default options from given file only.
命令行格式Command-Line Format --defaults-extra-file=path--defaults-extra-file=path类型Type 字符串String 默认值Default Value [none][none]在读取全局文件之后读取给定文件。Read given file after global files are read.
命令行格式Command-Line Format --defaults-group-suffix=string类型Type 字符串String 默认值Default Value [none][none]也读取组合了 concat(group, suffix) 的组。Also read groups with concat(group, suffix).
命令行格式Command-Line Format --login-path=path类型Type 字符串String 默认值Default Value [none][none]从登录文件读取给定路径。Read given path from login file.
命令行格式Command-Line Format --no-login-paths跳过从登录路径文件读取选项。Skips reading options from the login path file.
命令行格式Command-Line Format --help--help显示帮助文本并退出。Display help text and exit.
命令行格式Command-Line Format --ndb-connectstring=connection_string类型Type 字符串String 默认值Default Value [none][none]设置用于连接到 ndb_mgmd 的连接字符串。语法：
[nodeid=。覆盖id;][host=]hostname[:port]NDB_CONNECTSTRING和my.cnf中的条目。Set connection string for connecting to ndb_mgmd. Syntax:[nodeid=. Overrides entries inid;][host=]hostname[:port]NDB_CONNECTSTRINGandmy.cnf.命令行格式Command-Line Format --ndb-mgm-tls=level类型Type 枚举Enumeration 默认值Default Value relaxedrelaxed有效值Valid Values relaxedrelaxedstrictstrict设置连接到管理服务器所需的 TLS 支持级别；可以是
relaxed或strict。relaxed（默认）表示尝试建立 TLS 连接，但不要求成功；strict表示连接必须使用 TLS。Sets the level of TLS support required to connect to the management server; one ofrelaxedorstrict.relaxed(the default) means that a TLS connection is attempted, but success is not required;strictmeans that TLS is required to connect.命令行格式Command-Line Format --ndb-mgmd-host=connection_string类型Type 字符串String 默认值Default Value [none][none]同
--ndb-connectstring。Same as--ndb-connectstring.命令行格式Command-Line Format --ndb-nodeid=#类型Type 整数Integer 默认值Default Value [none][none]为此节点设置节点 ID，覆盖任何由
--ndb-connectstring设置的 ID。Set node ID for this node, overriding any ID set by--ndb-connectstring.--ndb-optimized-node-selection命令行格式Command-Line Format --ndb-optimized-node-selection启用事务节点选择的优化。默认启用；使用
--skip-ndb-optimized-node-selection来禁用。Enable optimizations for selection of nodes for transactions. Enabled by default; use--skip-ndb-optimized-node-selectionto disable.命令行格式Command-Line Format --ndb-tls-search-path=list类型Type 路径名Path name 默认值（Unix）Default Value (Unix) $HOME/ndb-tls$HOME/ndb-tls默认值（Windows）Default Value (Windows) $HOMEDIR/ndb-tls指定用于搜索 CA 文件的目录列表。在 Unix 平台上，目录名称用冒号 (
:) 分隔；在 Windows 系统上，使用分号 (;) 作为分隔符。目录引用可以是相对路径或绝对路径；它可以包含一个或多个环境变量，每个变量以美元符号 ($) 开头，并在使用前进行展开。Specify a list of directories to search for a CA file. On Unix platforms, the directory names are separated by colons (:); on Windows systems, the semicolon character (;) is used as the separator. A directory reference may be relative or absolute; it may contain one or more environment variables, each denoted by a prefixed dollar sign ($), and expanded prior to use.搜索从最左边的命名目录开始，按从左到右的顺序进行，直到找到文件。空字符串表示空搜索路径，这会导致所有搜索失败。由单个点 (
.) 组成的字符串表示搜索路径仅限于当前工作目录。Searching begins with the leftmost named directory and proceeds from left to right until a file is found. An empty string denotes an empty search path, which causes all searches to fail. A string consisting of a single dot (.) indicates that the search path limited to the current working directory.如果未提供搜索路径，则使用编译时的默认值。此值取决于所使用的平台：在 Windows 上，它是
\ndb-tls；在其他平台（包括 Linux）上，它是$HOME/ndb-tls。可以通过使用-DWITH_NDB_TLS_SEARCH_PATH编译 NDB Cluster 来覆盖该值。If no search path is supplied, the compiled-in default value is used. This value depends on the platform used: On Windows, this is\ndb-tls; on other platforms (including Linux), it is$HOME/ndb-tls. This can be overridden by compiling NDB Cluster using-DWITH_NDB_TLS_SEARCH_PATH.命令行格式Command-Line Format --no-defaults--no-defaults除了登录文件之外，不从任何配置文件读取默认选项。Do not read default options from any option file other than login file.
命令行格式Command-Line Format --print-defaults打印程序参数列表然后退出。Print program argument list and exit.
命令行格式Command-Line Format --usage显示帮助文本并退出；与
--help相同。Display help text and exit; same as--help.命令行格式Command-Line Format --version显示版本信息并退出。Display version information and exit.
您可以通过在调用此命令时列出由空格分隔的表名，从同一数据库的多个表中获取行数，如 示例输出 中所示。You can obtain row counts from multiple tables in the same database by listing the table names separated by spaces when invoking this command, as shown under Sample Output.
示例输出Sample Output
$> ./ndb_select_count -c localhost -d ctest1 fish dogs
6 records in table fish
4 records in table dogs