1========== 2 Glossary 3========== 4 5.. glossary:: 6 7 UUID 8 Universally Unique IDentifier which uniquely identifies the state and the 9 sequence of changes node undergoes. 128-bit UUID is a classic DCE UUID 10 Version 1 (based on current time and MAC address). Although in theory this 11 UUID could be generated based on the real MAC-address, in the Galera it is 12 always (without exception) based on the generated pseudo-random addresses 13 ("locally administered" bit in the node address (in the UUID structure) is 14 always equal to unity). 15 16 Complete structure of the 128-bit UUID field and explanation for its 17 generation are as follows: 18 19 ===== ==== ======= ===================================================== 20 From To Length Content 21 ===== ==== ======= ===================================================== 22 0 31 32 Bits 0-31 of Coordinated Universal Time (UTC) as a 23 count of 100-nanosecond intervals since 00:00:00.00, 24 15 October 1582, encoded as big-endian 32-bit number. 25 32 47 16 Bits 32-47 of UTC as a count of 100-nanosecond 26 intervals since 00:00:00.00, 15 October 1582, encoded 27 as big-endian 16-bit number. 28 48 59 12 Bits 48-59 of UTC as a count of 100-nanosecond 29 intervals since 00:00:00.00, 15 October 1582, encoded 30 as big-endian 16-bit number. 31 60 63 4 UUID version number: always equal to 1 (DCE UUID). 32 64 69 6 most-significants bits of random number, which 33 generated from the server process PID and Coordinated 34 Universal Time (UTC) as a count of 100-nanosecond 35 intervals since 00:00:00.00, 15 October 1582. 36 70 71 2 UID variant: always equal to binary 10 (DCE variant). 37 72 79 8 8 least-significant bits of random number, which 38 generated from the server process PID and Coordinated 39 Universal Time (UTC) as a count of 100-nanosecond 40 intervals since 00:00:00.00, 15 October 1582. 41 80 80 1 Random bit ("unique node identifier"). 42 81 81 1 Always equal to the one ("locally administered MAC 43 address"). 44 82 127 46 Random bits ("unique node identifier"): readed from 45 the :file:`/dev/urandom` or (if :file:`/dev/urandom` 46 is unavailable) generated based on the server process 47 PID, current time and bits of the default "zero node 48 identifier" (entropy data). 49 ===== ==== ======= ===================================================== 50 51 LSN 52 Each InnoDB page (usually 16kb in size) contains a log sequence number, or 53 LSN. The LSN is the system version number for the entire database. Each 54 page's LSN shows how recently it was changed. 55 56 innodb_file_per_table 57 By default, all InnoDB tables and indexes are stored in the system 58 tablespace on one file. This option causes the server to create one 59 tablespace file per table. To enable it, set it on your configuration file, 60 61 .. code-block:: text 62 63 [mysqld] 64 innodb_file_per_table 65 66 or start the server with ``--innodb_file_per_table``. 67 68 innodb_expand_import 69 This feature of |Percona Server| implements the ability to import 70 arbitrary :term:`.ibd` files exported using the |Percona XtraBackup| 71 :option:`--export` option. 72 73 See the `the full documentation 74 <http://www.percona.com/doc/percona-server/5.5/management/innodb_expand_import.html>`_ 75 for more information. 76 77 innodb_data_home_dir 78 The directory (relative to :term:`datadir`) where the database server 79 stores the files in a shared tablespace setup. This option does not affect 80 the location of :term:`innodb_file_per_table`. For example: 81 82 .. code-block:: text 83 84 [mysqld] 85 innodb_data_home_dir = ./ 86 87 innodb_data_file_path 88 Specifies the names, sizes and location of shared tablespace files: 89 90 .. code-block:: text 91 92 [mysqld] 93 innodb_data_file_path=ibdata1:50M;ibdata2:50M:autoextend 94 95 innodb_log_group_home_dir 96 Specifies the location of the |InnoDB| log files: 97 98 .. code-block:: text 99 100 [mysqld] 101 innodb_log_group_home=/var/lib/mysql 102 103 innodb_buffer_pool_size 104 The size in bytes of the memory buffer to cache data and indexes of 105 |InnoDB|'s tables. This aims to reduce disk access to provide better 106 performance. By default: 107 108 .. code-block:: text 109 110 [mysqld] 111 innodb_buffer_pool_size=8MB 112 113 InnoDB 114 Storage engine which provides ACID-compliant transactions and foreign 115 key support, among others improvements over :term:`MyISAM`. It is the 116 default engine for |MySQL| as of the 8.0 series. 117 118 MyISAM 119 Previous default storage engine for |MySQL| for versions prior to 5.5. It 120 doesn't fully support transactions but in some scenarios may be faster 121 than :term:`InnoDB`. Each table is stored on disk in 3 files: 122 :term:`.frm`, :term:`.MYD`, :term:`.MYI`. 123 124 XtraDB 125 *Percona XtraDB* is an enhanced version of the InnoDB storage engine, 126 designed to better scale on modern hardware, and including a variety of 127 other features useful in high performance environments. It is fully 128 backwards compatible, and so can be used as a drop-in replacement for 129 standard InnoDB. More information `here 130 <https://www.percona.com/doc/percona-server/5.6/percona_xtradb.html>`_. 131 132 my.cnf 133 This file refers to the database server's main configuration file. Most 134 Linux distributions place it as :file:`/etc/mysql/my.cnf` or 135 :file:`/etc/my.cnf`, but the location and name depends on the particular 136 installation. Note that this is not the only way of configuring the 137 server, some systems does not have one even and rely on the command 138 options to start the server and its defaults values. 139 140 datadir 141 The directory in which the database server stores its databases. Most Linux 142 distribution use :file:`/var/lib/mysql` by default. 143 144 xbcrypt 145 To support encryption and decryption of the backups, a new tool xbcrypt 146 was introduced to |Percona XtraBackup|. This utility has been modeled 147 after The xbstream binary to perform encryption and decryption outside of 148 |Percona XtraBackup|. 149 150 xbstream 151 To support simultaneous compression and streaming, |Percona XtraBackup| uses the 152 xbstream format. For more information see :option:`--stream` 153 154 ibdata 155 Default prefix for tablespace files, e.g. :file:`ibdata1` is a 10MB 156 auto-extensible file that |MySQL| creates for the shared tablespace by 157 default. 158 159 .frm 160 For each table, the server will create a file with the ``.frm`` extension 161 containing the table definition (for all storage engines). 162 163 .ibd 164 On a multiple tablespace setup (:term:`innodb_file_per_table` enabled), 165 |MySQL| will store each newly created table on a file with a ``.ibd`` 166 extension. 167 168 .MYD 169 Each |MyISAM| table has ``.MYD`` (MYData) file which contains the data on 170 it. 171 172 .MYI 173 Each |MyISAM| table has ``.MYI`` (MYIndex) file which contains the table's 174 indexes. 175 176 .exp 177 Files with the ``.exp`` extension are created by |Percona XtraBackup| per 178 each |InnoDB| tablespace when the :option:`--export` option is 179 used on prepare. These files can be used to import those tablespaces on 180 |Percona Server| 5.5 or lower versions, see :doc:`restoring individual 181 tables <xtrabackup_bin/restoring_individual_tables>`". 182 183 .MRG 184 Each table using the :program:`MERGE` storage engine, besides of a 185 :term:`.frm` file, will have :term:`.MRG` file containing the names of the 186 |MyISAM| tables associated with it. 187 188 .TRG 189 File containing the Triggers associated to a table, e.g. 190 `:file:`mytable.TRG`. With the :term:`.TRN` file, they represent all the 191 Trigger definitions. 192 193 .TRN 194 File containing the Triggers' Names associated to a table, e.g. 195 `:file:`mytable.TRN`. With the :term:`.TRG` file, they represent all the 196 Trigger definitions. 197 198 .ARM 199 Each table with the :program:`Archive Storage Engine` has ``.ARM`` file 200 which contains the metadata of it. 201 202 .ARZ 203 Each table with the :program:`Archive Storage Engine` has ``.ARZ`` file 204 which contains the data of it. 205 206 .CSM 207 Each table with the :program:`CSV Storage Engine` has ``.CSM`` file which 208 contains the metadata of it. 209 210 .CSV 211 Each table with the :program:`CSV Storage` engine has ``.CSV`` file which 212 contains the data of it (which is a standard Comma Separated Value file). 213 214 .opt 215 |MySQL| stores options of a database (like charset) in a file with a 216 :file:`.opt` extension in the database directory. 217 218 .par 219 Each partitioned table has .par file which contains metadata about the 220 partitions. 221