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1 {{box cssClass="floatinginfobox" title="**Contents**"}}
2 {{toc/}}
3 {{/box}}
5 = Compatibility Considerations =
7 See [[Database support strategy>>dev:Community.DatabaseSupportStrategy]] for the supported versions.
9 == MyISAM storage engine ==
11 MyISAM (the default storage engine for MySQL until release 5.5.5 in 2010) does not support transactions. If there is an error while data is being saved to the database, XWiki will attempt to roll back the transaction to its previous known good state. If you use MyISAM, it will do nothing, leaving the database in whatever state it was in when the error occurred.
13 {{warning}}
14 If you use MySQL with any engine that does not support transactions, you will most likely corrupt your database.** We highly recommend using a storage engine such as InnoDB which supports transactions.**
15 {{/warning}}
17 == MySQL versions older than 5.0 ==
19 XWiki does not fully work with MySQL versions 4.x or lower, due to several limitations of the way the SQL standards are implemented in MySQL, limited support for non-latin1 encodings, the flaky integration of Hibernate and MySQL 4, and other things. Most parts of the application work fine, but there are some parts that cannot be easily fixed, so if you must use MySQL 4.x, you're doing it on your own. MySQL 4 is pretty old and buggy, so we recommend upgrading.
21 == MySQL versions older than 5.7 and utf8mb4 ==
23 If you use utf8mb4 encoding, you won't be able to use a version of MySQL older than 5.7 out of the box because of a limitation in the default maximum size of the keys and the default row format.
25 == JDBC Driver Version ==
27 * It's recommended to use the latest version of the MySQL JDBC driver (8.x) if you're using MySQL 5.7+.
28 * If you're using XWiki < 13.3RC1, you should not use version 8.0.23 of the MySQL JDBC driver since it [[causes a problem with the Liquibase version used in XWiki>>]].
30 = Installation Steps =
32 Follow these instructions:
34 * Download and install [[MySQL>>]] 5.7 or greater.
35 * Start the MySQL server. You can do that in several ways. For example use {{code language="shell"}}mysqld --console{{/code}}
36 * Create the wiki database. You can use the name you want for the database, but you will have to set the hibernate configuration file and ##xwiki.cfg## file accordingly.(((
37 You can create the database in several ways. For example use:
39 {{code language="shell"}}
40 mysql -u root -e "create database xwiki default character set utf8mb4 collate utf8mb4_bin"
41 {{/code}}
42 )))
43 * Create the ##xwiki## user with password ##xwiki##(((
44 {{code language="shell"}}
45 mysql -u root -e "CREATE USER 'xwiki'@'localhost' IDENTIFIED BY 'xwiki'";
46 {{/code}}
47 )))
48 * Give privileges to the ##xwiki## user for accessing and creating databases (for the multi wiki support). Specifically the ##xwiki## users needs permissions to be able to execute {{code language="sql"}}CREATE DATABASE{{/code}}, {{code language="sql"}}DROP SCHEMA{{/code}}, and then all CRUD operations on tables. Note that the command below should be tuned to be more restrictive as granting all permissions is not required:(((
49 {{code language="shell"}}
50 mysql -u root -e "grant all privileges on *.* to xwiki@localhost"
51 {{/code}}
52 )))
53 * If the above command fails with a password-does-not-meet-requirements error, uninstall the MySQL password_validate plugin or pick a more complex password and update the password used by default in ##hibernate.cfg.xml##:(((
54 {{code language="shell"}}
55 mysql -u root -p -e "uninstall plugin validate_password;"
56 {{/code}}
57 )))
58 * Please make sure that the DNS-name "localhost" is defined in your hosts-file (i.e. ##/etc/hosts##)
59 * You need to have the MySQL JDBC Driver JAR (named ##mysql-connector-java*.jar##) installed in XWiki's WAR file. If this file isn't present in XWiki's ##WEB-INF/lib## directory you'll need to download it and copy it there. You can download it from the [[MySQL Connector/J Driver page>>]] or directly from the [[Maven Central Repository>>]].(((
60 {{warning}}
61 You need the 5.x version or higher. The 3.x version doesn't handle Boolean data correctly and will either throw errors or will make all documents hidden by default.
62 {{/warning}}
63 )))
64 * Now you need to tell XWiki to use MySQL. To do this, edit the ##WEB-INF/hibernate.cfg.xml## file where you have expanded the XWiki WAR file and replace the matching properties with the following ones:(((
65 {{code language="xml"}}
66 <property name="connection.url">jdbc:mysql://localhost/xwiki</property>
67 <property name="connection.username">xwiki</property>
68 <property name="connection.password">xwiki</property>
69 <property name="connection.driver_class">com.mysql.jdbc.Driver</property>
70 <property name="dialect">org.hibernate.dialect.MySQL5InnoDBDialect</property>
71 <property name="connection.useUnicode">true</property>
72 <property name="connection.characterEncoding">UTF-8</property>
73 {{/code}}
75 {{info}}
76 * By default MySQL only accepts packets that are smaller than 1MB. If you get the "Packet for query is too large (max_allowed_packet)" error then see the [[Packet too large error page>>]]. For example to increase the packet size to 32M you could start the MySQL server with {{code language='shell'}}mysqld --console --max_allowed_packet=32M{{/code}} or you can modify directly the ##my.cnf## configuration file to set this value permanently.
77 * If an empty XWiki starts with no errors, but you are unable to upload the default set of pages (XAR file) try to increase the ##max_allowed_packet## parameter as shown above.
78 {{/info}}
79 )))
81 = Indexes =
83 See [[Database Administration>>Documentation.AdminGuide.Performances.Database Administration.WebHome]].
85 {{code language="mysql"}}
86 // Required
87 create index xwl_value on xwikilargestrings (xwl_value(50));
88 create index xwd_parent on xwikidoc (xwd_parent(50));
89 create index xwd_class_xml on xwikidoc (xwd_class_xml(20));
90 create index xda_docid1 on xwikiattrecyclebin (xda_docid);
91 create index solr_iterate_all_documents on xwikidoc (XWD_WEB(500), XWD_NAME(253), XWD_LANGUAGE(5), XWD_VERSION(10));
92 // Only required if you use stats (feature is off by default)
93 create index xws_number on xwikistatsdoc (XWS_NUMBER);
94 create index xws_classname on xwikistatsdoc (XWS_CLASSNAME);
95 create index xwr_number on xwikistatsreferer (XWR_NUMBER);
96 create index xwr_classname on xwikistatsreferer (XWR_CLASSNAME);
97 create index xwr_referer on xwikistatsreferer (XWR_REFERER(50));
98 create index xwv_user_agent on xwikistatsvisit (XWV_USER_AGENT(255));
99 create index xwv_cookie on xwikistatsvisit (XWV_COOKIE(255));
100 create index xwv_classname on xwikistatsvisit (XWV_CLASSNAME);
101 create index xwv_number on xwikistatsvisit (XWV_NUMBER);
102 {{/code}}
104 {{info}}
105 Note to XWiki developers: The following indexes could be created automatically though since they're less than 255 characters and thus should be added in a future version of XWiki so that they don't need to be created manually:
107 {{code language="mysql"}}
108 create index xws_number on xwikistatsdoc (XWS_NUMBER);
109 create index xws_classname on xwikistatsdoc (XWS_CLASSNAME);
110 create index xwr_number on xwikistatsreferer (XWR_NUMBER);
111 create index xwr_classname on xwikistatsreferer (XWR_CLASSNAME);
112 create index xwv_classname on xwikistatsvisit (XWV_CLASSNAME);
113 create index xwv_number on xwikistatsvisit (XWV_NUMBER);
114 create index xda_docid1 on xwikiattrecyclebin (xda_docid);
115 {{/code}}
116 {{/info}}
118 = Tips =
120 == MySQL 8 ==
122 * If you're using MySQL 8+ you'll need to configure MySQL with native password: ##default-authentication-plugin=mysql_native_password##.
123 * You'll also be able to switch from ##com.mysql.jdbc.Driver## to ##com.mysql.cj.jdbc.Driver## JDBC driver (since the previous driver class is now deprecated).
124 * If you get the following error then you'll need to force the timezone to use either by setting it in:(((
125 * The MySQL conf file on the server
126 * In the XWiki ##hibernate.cfg.xml## file in the ##hibernate.connection.serverTimezone## property (e.g. ##<property name="hibernate.connection.serverTimezone">Europe/Berlin</property>##).
127 * In the XWiki ##hibernate.cfg.xml## file inside the JDBC URL string as in ##jdbc:mysql:~/~/localhost:3306/myschema?serverTimezone=UTC##
129 {{code language="none"}}
130 The server timezone value 'CDT' is unrecognized or represents more than one timezone. You must configure either the server or JDBC driver (via the serverTimezone configuration property) to use a more specifc timezone value if you want to utilize timezone support.
131 {{/code}}
133 For more details see [[this explanation post>>]].
134 )))
136 == Convert a database from latin1 (or collation utf8_ci) to utf8mb4/utf8mb4_bin ==
138 {{code language="shell"}}
139 #!/bin/bash
141 db=xwiki
142 to_character_set=utf8mb4
143 to_collation=utf8mb4_bin
145 mysql_cmd="mysql -u root"
147 $mysql_cmd -e "ALTER DATABASE $db CHARACTER SET $to_character_set COLLATE $to_collation;"
149 TBL_LIST=$($mysql_cmd -N -s -r -e "use $db;show tables;")
151 for tbl_name in $TBL_LIST;
152 do
153 $mysql_cmd -e "alter table $db.$tbl_name convert to character set $to_character_set collate $to_collation;"
154 done
156 echo "Here the result of the operation:"
158 {{/code}}
160 (% class="box infomessage" %)
161 (((
162 In case the above script fails to convert some rows with "ERROR 1833 (HY000) at line 1: Cannot change column 'columnname': used in a foreign key constraint 'FK2bj2ghquiq79toomkvugw7iie' of table 'xwiki.tablename', you can drop the foreign keys, convert the columns and then restart xWiki. Hibernate will re-create the dropped indexes automatically.
163 )))
165 You can also look at [[this snippet to perform this conversion inside XWiki>>snippets:Extension.Migrate MySQL databases to utf8mb4]].
167 == Convert from MyISAM to InnoDB ==
169 {{code language="shell"}}
170 #!/bin/bash
175 DATABASES=$(mysql -N -s -r -e 'show databases'|grep -v ^information_schema$|grep -v ^mysql$)
178 for db in $DATABASES
179 do
181 echo "Working on database $db..."
182 echo ""
184 TABLES=$(mysql -N -s -r -e "show tables from $db;")
186 for tb in $TABLES
187 do
191 done
193 $MYSQL_COMMAND -e "SELECT table_name,Engine,table_collation FROM information_schema.tables WHERE table_schema = DATABASE();"
195 echo ""
196 echo ""
198 done
199 {{/code}}
201 = Troubleshooting =
203 == Unable to login to MySQL Console ==
205 When running {{code language="shell"}}mysql -u root -e "create database xwiki default character set utf8mb4{{/code}} you may get a {{code}}ERROR 1045 (28000): Access denied for user 'xwiki'@'localhost' (using password: YES){{/code}} error.
206 This means that you have a password set for the MySQL root user, but you are not specifying it in the console command. You must also use the //-p// parameter. Using this you will be prompted to enter the password and be allowed to login to the MySQL console and create the database.
208 == Can't create test file ==
210 When running ##mysqld ~-~-console## you may get the following (especially if you're on a Mac):
212 {{code language="none"}}
213 071111 17:20:53 [Warning] Can't create test file /usr/local/mysql-5.0.45-osx10.4-i686/data/Vincent.lower-test
214 071111 17:20:53 [Warning] Can't create test file /usr/local/mysql-5.0.45-osx10.4-i686/data/Vincent.lower-test
215 mysqld: Can't change dir to '/usr/local/mysql-5.0.45-osx10.4-i686/data/' (Errcode: 13)
216 071111 17:20:53 [ERROR] Aborting
217 {{/code}}
219 To start MySQL run the following command instead:
221 {{code}}
222 sudo /usr/local/mysql/bin/mysqld_safe --user=mysql
223 {{/code}}
225 == Data Truncation Error ==
227 If you receive an Exception like the following while installing/upgrading XWiki, chances are that you are using an outdated version of MySQLConnectorJ.
229 {{code language="none"}}
230 Caused by: java.sql.BatchUpdateException: Data truncation: Out of
231 range value adjusted for column 'XWD_HIDDEN' at row 1
232 at com.mysql.jdbc.PreparedStatement.executeBatch(
233 at org.apache.commons.dbcp.DelegatingStatement.executeBatch(
234 at org.apache.commons.dbcp.DelegatingStatement.executeBatch(
235 at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(
236 at org.hibernate.jdbc.AbstractBatcher.executeBatch(
237 {{/code}}
239 On Linux, mysql-connector-java-3.x has proven **not** to work due to a bug in the handling of UTF-8 and lack of support for Boolean types.
241 Upgrading to the latest version of MySQLConnectorJ should solve such an error in most of the cases.
243 == HTTP 500 Error ==
245 {{code language="none"}}
246 HTTP Status 500 -
248 type Exception report
250 message
252 descriptionThe server encountered an internal error () that prevented it from fulfilling this request.
254 exception
256 javax.servlet.ServletException: com.xpn.xwiki.XWikiException: Error number 3 in 0: Could not initialize main XWiki context
257 Wrapped Exception: Error number 3001 in 3: Cannot load class from param
258 Wrapped Exception: Error number 0 in 3: Exception while hibernate execute
259 Wrapped Exception: Could not create a DBCP pool. There is an error in the hibernate configuration file, please review it.
261 root cause
263 com.xpn.xwiki.XWikiException: Error number 3 in 0: Could not initialize main XWiki context
264 Wrapped Exception: Error number 3001 in 3: Cannot load class from param
265 Wrapped Exception: Error number 0 in 3: Exception while hibernate execute
266 Wrapped Exception: Could not create a DBCP pool. There is an error in the hibernate configuration file, please review it.
267 {{/code}}
269 In this case, try to disable **skip-networking** in MySQL *.ini file. Thanks a lot //M Rawash// (see his comment below).
271 == Unknown database 'xwiki' ==
273 If you get the following error:
275 {{code language="none"}}
276 Caused by: class com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown database 'xwiki'
277 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
278 at sun.reflect.NativeConstructorAccessorImpl.newInstance(
279 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(
280 at java.lang.reflect.Constructor.newInstance(
281 at com.mysql.jdbc.Util.handleNewInstance(
282 at com.mysql.jdbc.Util.getInstance(
283 at com.mysql.jdbc.SQLError.createSQLException(
284 at com.mysql.jdbc.MysqlIO.checkErrorPacket(
285 at com.mysql.jdbc.MysqlIO.checkErrorPacket(
286 at com.mysql.jdbc.MysqlIO.sendCommand(
287 at com.mysql.jdbc.MysqlIO.sqlQueryDirect(
288 at com.mysql.jdbc.ConnectionImpl.execSQL(
289 at com.mysql.jdbc.ConnectionImpl.setCatalog(
290 at org.apache.commons.dbcp.DelegatingConnection.setCatalog(
291 at org.apache.commons.dbcp.DelegatingConnection.setCatalog(
292 at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.setCatalog(
293 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
294 at sun.reflect.NativeMethodAccessorImpl.invoke(
295 at sun.reflect.DelegatingMethodAccessorImpl.invoke(
296 at java.lang.reflect.Method.invoke(
297 at org.hibernate.jdbc.BorrowedConnectionProxy.invoke(
298 at com.sun.proxy.$Proxy47.setCatalog(Unknown Source)
299 at
300 at
301 at
302 at
303 ...
304 {{/code}}
306 It means that XWiki could connect to your database but there's no ##xwiki## schema available there. This is the default name of the schema XWiki is looking for, for the main wiki database.
308 It probably means you've created a database named other than ##xwiki## (for example you might have created a database named ##abcd## and set the following connection URL in your ##hibernate.cfg## file: {{code language="none"}}<property name="connection.url">jdbc:mysql://localhost/abcd</property>{{/code}}).
310 If this is the case [[you need to tell XWiki that you're using a different schema by setting the ##xwiki.db## configuration property>>platform:AdminGuide.Configuration#HConfigurethenamesofdatabaseschemas]].
312 == MySQLSyntaxErrorException: Row size too large (> 8126) ==
314 if you get the following error:
316 {{code language="none"}}
317 MySQLSyntaxErrorException: Row size too large (> 8126).
318 Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help.
319 In current row format, BLOB prefix of 768 bytes is stored inline.
320 {{/code}}
322 When you are using a MySQL Server 5.6.20 you can get a "row size too large error."
323 In the release notes, it is explained that a innodb_log_file_size which is too small will trigger a "Row size too large error."
325 You can solve the problem by changing the innodb_log_file_size in the my.ini text file.
326 Find more details in the link below.

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