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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) does not support transactions. If there is an error while data is being saved to the database, XWiki will attempt to rollback 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 the default engine MyISAM, 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 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 ase_page_date on activitystream_events (ase_page, ase_date);
92 create index ase_param1 on activitystream_events (ase_param1(200));
93 create index ase_param2 on activitystream_events (ase_param2(200));
94 create index ase_param3 on activitystream_events (ase_param3(200));
95 create index ase_param4 on activitystream_events (ase_param4(200));
96 create index ase_param5 on activitystream_events (ase_param5(200));
97 create index solr_iterate_all_documents on xwikidoc (XWD_WEB, XWD_NAME, XWD_LANGUAGE, XWD_VERSION);
98 // Only required if you use stats (feature is off by default)
99 create index xws_number on xwikistatsdoc (XWS_NUMBER);
100 create index xws_classname on xwikistatsdoc (XWS_CLASSNAME);
101 create index xwr_number on xwikistatsreferer (XWR_NUMBER);
102 create index xwr_classname on xwikistatsreferer (XWR_CLASSNAME);
103 create index xwr_referer on xwikistatsreferer (XWR_REFERER(50));
104 create index xwv_user_agent on xwikistatsvisit (XWV_USER_AGENT(255));
105 create index xwv_cookie on xwikistatsvisit (XWV_COOKIE(255));
106 create index xwv_classname on xwikistatsvisit (XWV_CLASSNAME);
107 create index xwv_number on xwikistatsvisit (XWV_NUMBER);
108 {{/code}}
110 {{info}}
111 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:
113 {{code language="mysql"}}
114 create index xws_number on xwikistatsdoc (XWS_NUMBER);
115 create index xws_classname on xwikistatsdoc (XWS_CLASSNAME);
116 create index xwr_number on xwikistatsreferer (XWR_NUMBER);
117 create index xwr_classname on xwikistatsreferer (XWR_CLASSNAME);
118 create index xwv_classname on xwikistatsvisit (XWV_CLASSNAME);
119 create index xwv_number on xwikistatsvisit (XWV_NUMBER);
120 create index xda_docid1 on xwikiattrecyclebin (xda_docid);
121 {{/code}}
122 {{/info}}
124 = Tips =
126 == MySQL 8 ==
128 * If you're using MySQL 8+ you'll need to configure MySQL with native password: ##default-authentication-plugin=mysql_native_password##.
129 * 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).
130 * If you get the following error then you'll need to force the timezone to use either by setting it in:(((
131 * The MySQL conf file on the server
132 * In the XWiki ##hibernate.cfg.xml## file in the ##hibernate.connection.serverTimezone## property (e.g. ##<property name="hibernate.connection.serverTimezone">Europe/Berlin</property>##).
133 * In the XWiki ##hibernate.cfg.xml## file inside the JDBC URL string as in ##jdbc:mysql:~/~/localhost:3306/myschema?serverTimezone=UTC##
135 {{code language="none"}}
136 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.
137 {{/code}}
139 For more details see [[this explanation post>>]].
140 )))
142 == Convert a database from latin1 (or collation utf8_ci) to utf8mb4/utf8mb4_bin ==
144 {{code language="shell"}}
145 #!/bin/bash
147 db=xwiki
148 to_character_set=utf8mb4
149 to_collation=utf8mb4_bin
151 mysql_cmd="mysql -u root"
153 $mysql_cmd -e "ALTER DATABASE $db CHARACTER SET $to_character_set COLLATE $to_collation;"
155 TBL_LIST=$($mysql_cmd -N -s -r -e "use $db;show tables;")
157 for tbl_name in $TBL_LIST;
158 do
159 $mysql_cmd -e "alter table $db.$tbl_name convert to character set $to_character_set collate $to_collation;"
160 done
162 echo "Here the result of the operation:"
164 {{/code}}
166 You can also look at [[this snippet to perform this conversion inside XWiki>>snippets:Extension.Migrate MySQL databases to utf8mb4]].
168 == Convert from MyISAM to InnoDB ==
170 {{code language="shell"}}
171 #!/bin/bash
176 DATABASES=$(mysql -N -s -r -e 'show databases'|grep -v ^information_schema$|grep -v ^mysql$)
179 for db in $DATABASES
180 do
182 echo "Working on database $db..."
183 echo ""
185 TABLES=$(mysql -N -s -r -e "show tables from $db;")
187 for tb in $TABLES
188 do
192 done
194 $MYSQL_COMMAND -e "SELECT table_name,Engine,table_collation FROM information_schema.tables WHERE table_schema = DATABASE();"
196 echo ""
197 echo ""
199 done
200 {{/code}}
202 = Troubleshooting =
204 == Unable to login to MySQL Console ==
206 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.
207 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.
209 == Can't create test file ==
211 When running ##mysqld ~-~-console## you may get the following (especially if you're on a Mac):
213 {{code language="none"}}
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 071111 17:20:53 [Warning] Can't create test file /usr/local/mysql-5.0.45-osx10.4-i686/data/Vincent.lower-test
216 mysqld: Can't change dir to '/usr/local/mysql-5.0.45-osx10.4-i686/data/' (Errcode: 13)
217 071111 17:20:53 [ERROR] Aborting
218 {{/code}}
220 To start MySQL run the following command instead:
222 {{code}}
223 sudo /usr/local/mysql/bin/mysqld_safe --user=mysql
224 {{/code}}
226 == Data Truncation Error ==
228 If you receive an Exception like the following while installing/upgrading XWiki, chances are that you are using an outdated version of MySQLConnectorJ.
230 {{code language="none"}}
231 Caused by: java.sql.BatchUpdateException: Data truncation: Out of
232 range value adjusted for column 'XWD_HIDDEN' at row 1
233 at com.mysql.jdbc.PreparedStatement.executeBatch(
234 at org.apache.commons.dbcp.DelegatingStatement.executeBatch(
235 at org.apache.commons.dbcp.DelegatingStatement.executeBatch(
236 at org.hibernate.jdbc.BatchingBatcher.doExecuteBatch(
237 at org.hibernate.jdbc.AbstractBatcher.executeBatch(
238 {{/code}}
240 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.
242 Upgrading to the latest version of MySQLConnectorJ should solve such an error in most of the cases.
244 == HTTP 500 Error ==
246 {{code language="none"}}
247 HTTP Status 500 -
249 type Exception report
251 message
253 descriptionThe server encountered an internal error () that prevented it from fulfilling this request.
255 exception
257 javax.servlet.ServletException: com.xpn.xwiki.XWikiException: Error number 3 in 0: Could not initialize main XWiki context
258 Wrapped Exception: Error number 3001 in 3: Cannot load class from param
259 Wrapped Exception: Error number 0 in 3: Exception while hibernate execute
260 Wrapped Exception: Could not create a DBCP pool. There is an error in the hibernate configuration file, please review it.
262 root cause
264 com.xpn.xwiki.XWikiException: Error number 3 in 0: Could not initialize main XWiki context
265 Wrapped Exception: Error number 3001 in 3: Cannot load class from param
266 Wrapped Exception: Error number 0 in 3: Exception while hibernate execute
267 Wrapped Exception: Could not create a DBCP pool. There is an error in the hibernate configuration file, please review it.
268 {{/code}}
270 In this case, try to disable **skip-networking** in MySQL *.ini file. Thanks a lot //M Rawash// (see his comment below).
272 == Unknown database 'xwiki' ==
274 If you get the following error:
276 {{code language="none"}}
277 Caused by: class com.mysql.jdbc.exceptions.jdbc4.MySQLSyntaxErrorException: Unknown database 'xwiki'
278 at sun.reflect.NativeConstructorAccessorImpl.newInstance0(Native Method)
279 at sun.reflect.NativeConstructorAccessorImpl.newInstance(
280 at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(
281 at java.lang.reflect.Constructor.newInstance(
282 at com.mysql.jdbc.Util.handleNewInstance(
283 at com.mysql.jdbc.Util.getInstance(
284 at com.mysql.jdbc.SQLError.createSQLException(
285 at com.mysql.jdbc.MysqlIO.checkErrorPacket(
286 at com.mysql.jdbc.MysqlIO.checkErrorPacket(
287 at com.mysql.jdbc.MysqlIO.sendCommand(
288 at com.mysql.jdbc.MysqlIO.sqlQueryDirect(
289 at com.mysql.jdbc.ConnectionImpl.execSQL(
290 at com.mysql.jdbc.ConnectionImpl.setCatalog(
291 at org.apache.commons.dbcp.DelegatingConnection.setCatalog(
292 at org.apache.commons.dbcp.DelegatingConnection.setCatalog(
293 at org.apache.commons.dbcp.PoolingDataSource$PoolGuardConnectionWrapper.setCatalog(
294 at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
295 at sun.reflect.NativeMethodAccessorImpl.invoke(
296 at sun.reflect.DelegatingMethodAccessorImpl.invoke(
297 at java.lang.reflect.Method.invoke(
298 at org.hibernate.jdbc.BorrowedConnectionProxy.invoke(
299 at com.sun.proxy.$Proxy47.setCatalog(Unknown Source)
300 at
301 at
302 at
303 at
304 ...
305 {{/code}}
307 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.
309 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}}).
311 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]].
313 == MySQLSyntaxErrorException: Row size too large (> 8126) ==
315 if you get the following error:
317 {{code language="none"}}
318 MySQLSyntaxErrorException: Row size too large (> 8126).
319 Changing some columns to TEXT or BLOB or using ROW_FORMAT=DYNAMIC or ROW_FORMAT=COMPRESSED may help.
320 In current row format, BLOB prefix of 768 bytes is stored inline.
321 {{/code}}
323 When you are using a MySQL Server 5.6.20 you can get a "row size too large error."
324 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."
326 You can solve the problem by changing the innodb_log_file_size in the my.ini text file.
327 Find more details in the link below.

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