MySQL parameter features

The problems involved here are also my daily confusions. Now let's make a summary. It mainly describes two problems:

1. MySQL parameter features;

2. MySQL parameter settings;

We all know that there are many options under the command line, and these options will be followed by a bar, that is, "-"; two bars, that is "--", are there any macro rules for such complicated and complicated options? Others do not know. There are no more than 20 MySQL options. The following describes the MySQL parameters obtained by using the command: MySQL -- help:

mysql  Ver 14.12 Distrib 5.0.22, for Win32 (ia32)Copyright (C) 2002 MySQL ABThis software comes with ABSOLUTELY NO WARRANTY. This is free software,and you are welcome to modify and redistribute it under the GPL licenseUsage: mysql [OPTIONS] [database]  -?, --help          Display this help and exit.  -I, --help          Synonym for -?  --auto-rehash       Enable automatic rehashing. One doesn't need to use                      'rehash' to get table and field completion, but startup                      and reconnecting may take a longer time. Disable with                      --disable-auto-rehash.  -A, --no-auto-rehash                       No automatic rehashing. One has to use 'rehash' to get                      table and field completion. This gives a quicker start of                      mysql and disables rehashing on reconnect. WARNING:                      options deprecated; use --disable-auto-rehash instead.  -B, --batch         Don't use history file. Disable interactive behavior.                      (Enables --silent)  --character-sets-dir=name                       Directory where character sets are.  --default-character-set=name                       Set the default character set.  -C, --compress      Use compression in server/client protocol.  -#, --debug[=#]     This is a non-debug version. Catch this and exit  -D, --database=name Database to use.  --delimiter=name    Delimiter to be used.  -e, --execute=name  Execute command and quit. (Disables --force and history                      file)  -E, --vertical      Print the output of a query (rows) vertically.  -f, --force         Continue even if we get an sql error.  -g, --no-named-commands                       Named commands are disabled. Use \* form only, or use                      named commands only in the beginning of a line ending                      with a semicolon (;) Since version 10.9 the client now                      starts with this option ENABLED by default! Disable with                      '-G'. Long format commands still work from the first                      line. WARNING: option deprecated; use                      --disable-named-commands instead.  -G, --named-commands                       Enable named commands. Named commands mean this program's                      internal commands; see mysql> help . When enabled, the                      named commands can be used from any line of the query,                      otherwise only from the first line, before an enter.                      Disable with --disable-named-commands. This option is                      disabled by default.  -i, --ignore-spaces Ignore space after function names.  --local-infile      Enable/disable LOAD DATA LOCAL INFILE.  -b, --no-beep       Turn off beep on error.  -h, --host=name     Connect to host.  -H, --html          Produce HTML output.  -X, --xml           Produce XML output  --line-numbers      Write line numbers for errors.  -L, --skip-line-numbers                       Don't write line number for errors. WARNING: -L is                      deprecated, use long version of this option instead.  --no-tee            Disable outfile. See interactive help (\h) also. WARNING:                      option deprecated; use --disable-tee instead  -n, --unbuffered    Flush buffer after each query.  --column-names      Write column names in results.  -N, --skip-column-names                       Don't write column names in results. WARNING: -N is                      deprecated, use long version of this options instead.  -O, --set-variable=name                       Change the value of a variable. Please note that this                      option is deprecated; you can set variables directly with                      --variable-name=value.  --sigint-ignore     Ignore SIGINT (CTRL-C)  -o, --one-database  Only update the default database. This is useful for                      skipping updates to other database in the update log.  -p, --password[=name]                       Password to use when connecting to server. If password is                      not given it's asked from the tty.  -W, --pipe          Use named pipes to connect to server.  -P, --port=#        Port number to use for connection.  --prompt=name       Set the mysql prompt to this value.  --protocol=name     The protocol of connection (tcp,socket,pipe,memory).  -q, --quick         Don't cache result, print it row by row. This may slow                      down the server if the output is suspended. Doesn't use                      history file.  -r, --raw           Write fields without conversion. Used with --batch.  --reconnect         Reconnect if the connection is lost. Disable with                      --disable-reconnect. This option is enabled by default.  -s, --silent        Be more silent. Print results with a tab as separator,                      each row on new line.  --shared-memory-base-name=name                       Base name of shared memory.  -S, --socket=name   Socket file to use for connection.  --ssl               Enable SSL for connection (automatically enabled with                      other flags). Disable with --skip-ssl.  --ssl-key=name      X509 key in PEM format (implies --ssl).  --ssl-cert=name     X509 cert in PEM format (implies --ssl).  --ssl-ca=name       CA file in PEM format (check OpenSSL docs, implies                      --ssl).  --ssl-capath=name   CA directory (check OpenSSL docs, implies --ssl).  --ssl-cipher=name   SSL cipher to use (implies --ssl).  -t, --table         Output in table format.  -T, --debug-info    Print some debug info at exit.  --tee=name          Append everything into outfile. See interactive help (\h)                      also. Does not work in batch mode.  -u, --user=name     User for login if not current user.  -U, --safe-updates  Only allow UPDATE and DELETE that uses keys.  -U, --i-am-a-dummy  Synonym for option --safe-updates, -U.  -v, --verbose       Write more. (-v -v -v gives the table output format).  -V, --version       Output version information and exit.  -w, --wait          Wait and retry if connection is down.  --connect_timeout=# Number of seconds before connection timeout.  --max_allowed_packet=#                       Max packet length to send to, or receive from server  --net_buffer_length=#                       Buffer for TCP/IP and socket communication  --select_limit=#    Automatic limit for SELECT when using --safe-updates  --max_join_size=#   Automatic limit for rows in a join when using                      --safe-updates  --secure-auth       Refuse client connecting to server if it uses old                      (pre-4.1.1) protocol  --show-warnings     Show warnings after every statement.Default options are read from the following files in the given order:C:\my.ini C:\my.cnf C:\WINDOWS\my.ini C:\WINDOWS\my.cnf C:\Program Files\MySQL\MySQL Server 5.0\my.ini C:\Program Files\MySQL\MySQL Server 5.0\my.cnf The following groups are read: mysql clientThe following options may be given as the first argument:--print-defaultsPrint the program argument list and exit--no-defaultsDon't read default options from any options file--defaults-file=#Only read default options from the given file #--defaults-extra-file=# Read this file after the global files are readVariables (--variable-name=value)and boolean options {FALSE|TRUE}  Value (after reading options)--------------------------------- -----------------------------auto-rehash                       TRUEcharacter-sets-dir                (No default value)default-character-set             latin1compress                          FALSEdatabase                          (No default value)delimiter                         ;vertical                          FALSEforce                             FALSEnamed-commands                    FALSElocal-infile                      FALSEno-beep                           FALSEhost                              (No default value)html                              FALSExml                               FALSEline-numbers                      TRUEunbuffered                        FALSEcolumn-names                      TRUEsigint-ignore                     FALSEport                              3306prompt                            \u@\h:\d\r:\m:\s>quick                             FALSEraw                               FALSEreconnect                         TRUEshared-memory-base-name           (No default value)socket                            (No default value)ssl                               FALSEssl-key                           (No default value)ssl-cert                          (No default value)ssl-ca                            (No default value)ssl-capath                        (No default value)ssl-cipher                        (No default value)table                             FALSEdebug-info                        FALSEuser                              (No default value)safe-updates                      FALSEi-am-a-dummy                      FALSEconnect_timeout                   0max_allowed_packet                16777216net_buffer_length                 16384select_limit                      1000max_join_size                     1000000secure-auth                       FALSEshow-warnings                     TRUE

See it. It's very complicated. Let's take a look at the output in detail! They have the following rules:

1. "-" number: There are two "--" parameters in front, and two "--" and "--" in front of the same parameter. For example:

-- Secure-auth only has "--", while-U and -- user = Name have two;

2. "equal sign of a parameter": There are two possible conditions: equal sign and no equal sign;

A. "features on the right of the equal sign": "= Name" and "[= #]". Of course, there is also a non-equal sign;

After summing up the above three rules, we can draw the following conclusions:

1. when the same parameter has both-"and" -- ", for example,-u, -- user = Name, this indicates that this parameter can be set either in the command line or in the configuration file. The method set in the command line is-uusername, Which is set in the configuration file, add a line under the mysqld segment: User = "user" (why do we need to add double quotation marks here ?); You can set any other parameter with this feature;

2. the name on the right of the equal sign indicates that the value on the right is a string, which means that we need to add double quotation marks. When it is [= #], it indicates that the value on the right should be a number; if there is no equal sign, its value should be true or false. The default value is false;

The above conclusion is not a random one. You can actually test it. here we can use the MySQL -- Help Command output to verify it:

We will see the output of MySQL -- help posted above. Copy the second half of it here:

Variables (--variable-name=value)and boolean options {FALSE|TRUE}  Value (after reading options)--------------------------------- -----------------------------auto-rehash                       TRUEcharacter-sets-dir                (No default value)default-character-set             latin1compress                          FALSEdatabase                          (No default value)delimiter                         ;vertical                          FALSEforce                             FALSEnamed-commands                    FALSElocal-infile                      FALSEno-beep                           FALSEhost                              (No default value)html                              FALSExml                               FALSEline-numbers                      TRUEunbuffered                        FALSEcolumn-names                      TRUEsigint-ignore                     FALSEport                              3306prompt                            \u@\h:\d\r:\m:\s>quick                             FALSEraw                               FALSEreconnect                         TRUEshared-memory-base-name           (No default value)socket                            (No default value)ssl                               FALSEssl-key                           (No default value)ssl-cert                          (No default value)ssl-ca                            (No default value)ssl-capath                        (No default value)ssl-cipher                        (No default value)table                             FALSEdebug-info                        FALSEuser                              (No default value)safe-updates                      FALSEi-am-a-dummy                      FALSEconnect_timeout                   0max_allowed_packet                16777216net_buffer_length                 16384select_limit                      1000max_join_size                     1000000secure-auth                       FALSEshow-warnings                     TRUE

In the above two columns, the left column is the configurable parameter, and the right column is its current value. The analysis shows that the two conclusions above are correct. You can set it in the command line or configuration file according to the above conclusion, and then use MySQL -- help to output the above information to see the effect, there will be no error.

With the above guidelines as a guide, I believe that the configuration of MySQL parameters has more directionality, and no direction is terrible. This article expresses some jumps and requires you to have a certain understanding of MySQL.