Changes between Version 2 and Version 3 of TracUpgrade


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Aug 13, 2019, 3:52:01 PM (5 years ago)
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trac
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  • TracUpgrade

    v2 v3  
    1 = Upgrade Instructions = 
     1= Upgrade Instructions 
    22[[TracGuideToc]] 
    33[[PageOutline(2-4,,inline,unnumbered)]] 
    44 
    5 == Instructions == 
     5== Instructions 
    66 
    77Typically, there are seven steps involved in upgrading to a newer version of Trac: 
    … …  
    99=== 1. Bring your server off-line 
    1010 
    11 It is not a good idea to update a running server: the server processes may have parts of the current packages cached in memory, and updating the code will likely trigger [#ZipImportError internal errors].  
    12  
    13 === 2. Update the Trac Code === #UpdatetheTracCode 
    14  
    15 Get the new version as described in TracInstall, or your operating system specific procedure. 
    16  
    17 If you already have a 0.11 version of Trac installed via `easy_install`, it might be easiest to also use `easy_install` to upgrade your Trac installation: 
    18  
    19 {{{ 
    20 # easy_install --upgrade Trac==0.12 
    21 }}} 
    22  
    23 If you do a manual (not operating system-specific) upgrade, you should also stop any running Trac servers before the installation. Doing "hot" upgrades is not advised, especially on Windows ([trac:#7265]). 
     11It is not a good idea to update a running server: the server processes may have parts of the current packages cached in memory, and updating the code will likely trigger [#ZipImportError internal errors]. 
     12 
     13Although a database backup will be implicitly created by default when upgrading the environment, it is always a good idea to perform a full backup of the environment using the [TracBackup hotcopy] command before beginning. 
     14 
     15=== 2. Update the Trac Code #UpdatetheTracCode 
     16 
     17Get the new version as described in TracInstall, or through your operating system package manager. 
     18 
     19If you already an earlier version of Trac installed via `easy_install`, it might be easiest to also use `easy_install` to upgrade your Trac installation: 
     20 
     21{{{#!sh 
     22easy_install --upgrade Trac==1.2 
     23}}} 
    2424 
    2525You may also want to remove the pre-existing Trac code by deleting the `trac` directory from the Python `lib/site-packages` directory, or remove Trac `.egg` files from former versions. 
    … …  
    2929 * on MacOSX: `/Library/Python/2.X/site-packages` 
    3030 
    31 You may also want to remove the Trac `cgi-bin`, `htdocs`, `templates` and `wiki-default` directories that are commonly found in a directory called `share/trac`. (The exact location depends on your platform.) 
    32  
    33 This cleanup is not mandatory, but makes it easier to troubleshoot issues later on, as you won't waste your time looking at code or templates from a previous release that are not being used anymore... As usual, make a backup before actually deleting things. 
    34  
    35 === 3. Upgrade the Trac Environment === #UpgradetheTracEnvironment 
     31You may also want to remove the directory in which your static resources are [TracInstall#cgi-bin deployed]. The exact location depends on your platform. This cleanup is not mandatory, but makes it easier to troubleshoot issues later on, as your installation is uncluttered by code or templates from a previous release that is not used anymore. As usual, make a backup before actually removing things. 
     32 
     33=== 3. Upgrade the Trac Environment #UpgradetheTracEnvironment 
    3634 
    3735Environment upgrades are not necessary for minor version releases unless otherwise noted.  
    3836 
    3937After restarting, Trac should show the instances which need a manual upgrade via the automated upgrade scripts to ease the pain. These scripts are run via [TracAdmin trac-admin]: 
    40 {{{ 
     38{{{#!sh 
    4139trac-admin /path/to/projenv upgrade 
    4240}}} 
    4341 
    44 This command will do nothing if the environment is already up-to-date. 
     42This command will not have any effect if the environment is already up-to-date. 
    4543 
    4644Note that a backup of your database will be performed automatically prior to the upgrade.  
    47 This feature is relatively new for the PostgreSQL or MySQL database backends, so if it fails, you will have to backup the database manually. Then, to perform the actual upgrade, run: 
    48 {{{ 
     45This feature is relatively new for PostgreSQL or MySQL databases, so if it fails, you will have to backup the database manually. Then, to perform the actual upgrade: 
     46{{{#!sh 
    4947trac-admin /path/to/projenv upgrade --no-backup 
    5048}}} 
    … …  
    5250=== 4. Update the Trac Documentation === #UpdatetheTracDocumentation 
    5351 
    54 Every [TracEnvironment Trac environment] includes a copy of the Trac documentation for the installed version. As you probably want to keep the included documentation in sync with the installed version of Trac, [TracAdmin trac-admin] provides a command to upgrade the documentation: 
    55 {{{ 
     52By default, every [TracEnvironment Trac environment] includes a copy of the Trac documentation for the installed version. However, to keep the included documentation in sync with the installed version of Trac, use the following [TracAdmin trac-admin] command to upgrade the documentation: 
     53{{{#!sh 
    5654trac-admin /path/to/projenv wiki upgrade 
    5755}}} 
    … …  
    5957Note that this procedure will leave your `WikiStart` page intact. 
    6058 
    61  
    62 === 5. Refresh static resources === 
     59=== 5. Refresh static resources 
    6360 
    6461If you have set up a web server to give out static resources directly (accessed using the `/chrome/` URL) then you will need to refresh them using the same command: 
    65 {{{ 
     62{{{#!sh 
    6663trac-admin /path/to/env deploy /deploy/path 
    6764}}} 
    68 this will extract static resources and CGI scripts (`trac.wsgi`, etc) from new Trac version and its plugins into `/deploy/path`. 
     65 
     66This will extract static resources and CGI scripts (`trac.wsgi`, etc) from new Trac version and its plugins into `/deploy/path`. 
    6967 
    7068Some web browsers (IE, Opera) cache CSS and Javascript files aggressively, so you may need to instruct your users to manually erase the contents of their browser's cache, a forced refreshed (`<F5>`) should be enough. 
    … …  
    7371}}} 
    7472 
    75 === 6. Steps specific to a given Trac version  === 
    76 ==== Upgrading from Trac 0.12 to Trac 1.0 ==== #to1.0 
     73=== 6. Steps specific to a given Trac version 
     74 
     75==== Upgrading from Trac 1.0 to 1.2 #to1.2 
     76 
     77===== Python 2.5 no longer supported 
     78 
     79Upgrade Python to at least 2.6 or 2.7, but not 3.0 or greater. 
     80 
     81===== Obsolete Plugins 
     82 
     83Trac has added functionality equivalent to the following plugins: 
     84* [https://trac-hacks.org/wiki/AdminEnumListPlugin AdminEnumListPlugin] 
     85* [https://trac-hacks.org/wiki/DateFieldPlugin DateFieldPlugin]: see the **time** [TracTicketsCustomFields#AvailableFieldTypesandOptions custom field type] 
     86* [https://trac-hacks.org/wiki/GroupBasedRedirectionPlugin GroupBasedRedirectionPlugin]: the default handler can set as a user preference. 
     87* [https://trac-hacks.org/wiki/LinenoMacro LinenoMacro]: see WikiProcessors#AvailableProcessors 
     88* [https://trac-hacks.org/wiki/NeverNotifyUpdaterPlugin NeverNotifyUpdaterPlugin]: see [TracNotification#notification-subscriber-section notification subscribers] 
     89* [https://trac-hacks.org/wiki/QueryUiAssistPlugin QueryUiAssistPlugin]: see TracQuery#Filters. 
     90* [https://trac-hacks.org/wiki/TicketCreationStatusPlugin TicketCreationStatusPlugin]: see [#NewWorkflowActions] 
     91 
     92The plugins should be removed when upgrading Trac to 1.2. 
     93 
     94===== New workflow actions #NewWorkflowActions 
     95 
     96The ticket creation step is controlled with a workflow action. The default workflow has `create` and `create_and_assign` actions. The `create` action will always be added when upgrading the database. The `create_and_assign` action will be added if the workflow has an //assigned// state. You may want to edit your workflow after upgrading the database to customize the actions available on the //New Ticket// page. 
     97 
     98===== New permissions policy for read-only wiki pages 
     99 
     100Since 1.1.2 the read-only attribute of wiki pages is enabled and enforced only when `ReadonlyWikiPolicy` is in the list of active permission policies. If `[trac] permission_policy` has the default value `DefaultPermissionPolicy, LegacyAttachmentPolicy`, then `ReadonlyWikiPolicy` should be automatically appended to the list when upgrading the environment: 
     101{{{#!ini 
     102[trac] 
     103permission_policies = ReadonlyWikiPolicy, 
     104 DefaultPermissionPolicy, 
     105 LegacyAttachmentPolicy 
     106}}} 
     107 
     108If other permission policies are enabled, `trac.ini` will need to have `ReadonlyWikiPolicy` appended to the list of active `permission_policies`. See TracFineGrainedPermissions#ReadonlyWikiPolicy for additional details on the proper ordering. 
     109 
     110==== Upgrading from Trac 0.12 to Trac 1.0 #to1.0 
     111 
     112===== Python 2.4 no longer supported 
     113 
     114Upgrade Python to at least 2.5, but not 3.0. 
     115 
     116===== Obsolete Plugins 
     117 
     118Trac has added functionality equivalent to the following plugins: 
     119 
     120* [https://trac-hacks.org/wiki/BatchModifyPlugin BatchModifyPlugin] 
     121* ​[https://trac-hacks.org/wiki/GitPlugin GitPlugin] 
     122* [https://trac-hacks.org/wiki/OverrideEditPlugin OverrideEditPlugin] 
     123 
     124The plugins should be removed when upgrading Trac to 1.0. 
     125 
     126===== Subversion components not enabled by default for new installations 
    77127 
    78128The Trac components for Subversion support are no longer enabled by default. To enable the svn support, you need to make sure the `tracopt.versioncontrol.svn` components are enabled, for example by setting the following in the TracIni: 
    79 {{{ 
     129{{{#!ini 
    80130[components] 
    81131tracopt.versioncontrol.svn.* = enabled 
    82132}}} 
     133 
    83134The upgrade procedure should take care of this and change the TracIni appropriately, unless you already had the svn components explicitly disabled. 
    84135 
    85 Another step in the automatic upgrade will change the way the attachments are stored. If you're a bit paranoid, you might want to take a backup of the `attachments` directory before upgrading (but if you are, you already did a full copy of the environment, no?). In case the `attachments` directory contains some files which are //not// attachments, the last step of the migration to the new layout will fail: the deletion of the now unused `attachments` directory can't be done if there are still files and folders in it. You may ignore this error, but better go have a look to these files, move them elsewhere and remove the `attachments` directory manually to cleanup the environment. The attachments themselves are now all located in your environment below the `files/attachments` directory. 
    86  
    87  
    88 ==== Upgrading from Trac 0.11 to Trac 0.12 ==== 
    89  
    90 ===== Python 2.3 no longer supported ===== 
    91 The minimum supported version of python is now 2.4 
    92  
    93 ===== SQLite v3.x required ===== 
     136===== Attachments migrated to new location 
     137 
     138Another step in the automatic upgrade will change the way the attachments are stored. Create a backup of the `attachments` directory before upgrading. In case the `attachments` directory contains some files which are //not// attachments, the last step of the migration to the new layout will fail: the deletion of the now unused `attachments` directory can't be done if there are still files and folders in it. You may ignore this error, but better to move them elsewhere and remove the `attachments` directory manually. The attachments themselves are now all located in your environment below the `files/attachments` directory. 
     139 
     140===== Behavior of `[ticket] default_owner` changed 
     141 
     142Prior to 1.0, the owner field of new tickets always defaulted to `[ticket] default_owner` when the value was not empty. If the value was empty, the owner field defaulted to to the Component's owner. In 1.0 and later, the `default_owner` must be set to `< default >` to make new tickets default to the Component's owner. This change allows the `default_owner` to be set to an empty value if no default owner is desired. 
     143 
     144==== Upgrading from Trac 0.11 to Trac 0.12 
     145 
     146===== Python 2.3 no longer supported 
     147 
     148The minimum supported version of Python is now 2.4. 
     149 
     150===== SQLite v3.x required 
     151 
    94152SQLite v2.x is no longer supported. If you still use a Trac database of this format, you'll need to convert it to SQLite v3.x first. See [trac:PySqlite#UpgradingSQLitefrom2.xto3.x] for details. 
    95153 
    96 ===== PySqlite 2 required ===== 
    97 PySqlite 1.1.x is no longer supported. Please install 2.5.5 or later if possible (see [#Tracdatabaseupgrade Trac database upgrade] below). 
    98  
    99 ===== Multiple Repository Support ===== 
     154===== [trac:PySqlite] 2 required 
     155 
     156[trac:PySqlite] 1.1.x is no longer supported. Please install 2.5.5 or later if possible, see [#Tracdatabaseupgrade Trac database upgrade] below. 
     157 
     158===== Obsolete Plugins 
     159 
     160Trac has added functionality equivalent to the following plugins: 
     161 
     162* [https://trac-hacks.org/wiki/AutoQueryPlugin AutoQueryPlugin] 
     163* ​[https://trac-hacks.org/wiki/AdminConsoleProviderPatch AdminConsoleProviderPatch] 
     164* [https://trac-hacks.org/wiki/AnchorMacro AnchorMacro]: see WikiFormatting#SettingAnchors 
     165* [https://trac-hacks.org/wiki/TicketChangePlugin TicketChangePlugin]: see [TracPermissions#TicketSystem TICKET_EDIT_COMMENT permission] 
     166* [https://trac-hacks.org/wiki/TicketDeletePlugin TicketDeletePlugin]: see `tracopt.ticket.deleter` 
     167* [https://trac-hacks.org/wiki/SubversionLocationPlugin SubversionLocationPlugin]: see TracRepositoryAdmin#Repositories 
     168* [https://trac-hacks.org/wiki/WikiCreoleRendererPlugin WikiCreoleRendererPlugin]: see [trac:WikiCreole] 
     169* [https://trac-hacks.org/wiki/RepoRevisionSyntaxPlugin RepoRevisionSyntaxPlugin] (added in 0.12.1) 
     170 
     171The plugins should be removed when upgrading Trac to 0.12. 
     172 
     173===== Multiple Repository Support 
     174 
    100175The latest version includes support for multiple repositories. If you plan to add more repositories to your Trac instance, please refer to TracRepositoryAdmin#Migration. 
    101176 
    102 This may be of interest to users with only one repository, since there's now a way to avoid the potentially costly resync check at every request. 
    103  
    104 ===== Resynchronize the Trac Environment Against the Source Code Repository ===== 
    105  
    106 Each [TracEnvironment Trac environment] must be resynchronized against the source code repository in order to avoid errors such as "[http://trac.edgewall.org/ticket/6120 No changeset ??? in the repository]" while browsing the source through the Trac interface: 
    107  
    108 {{{ 
     177This may be of interest to users with only one repository, since there is now a way to avoid the potentially costly resync check at every request. 
     178 
     179===== Resynchronize the Trac Environment Against the Source Code Repository 
     180 
     181Each [TracEnvironment Trac environment] must be resynchronized against the source code repository in order to avoid errors such as "[trac:#6120 No changeset ??? in the repository]" while browsing the source through the Trac interface: 
     182 
     183{{{#!sh 
    109184trac-admin /path/to/projenv repository resync '*' 
    110185}}} 
    111186 
    112 ===== Improved repository synchronization ===== 
     187===== Improved repository synchronization 
     188 
    113189In addition to supporting multiple repositories, there is now a more efficient method for synchronizing Trac and your repositories. 
    114190 
    … …  
    117193Note that if you were using the `trac-post-commit-hook`, ''you're strongly advised to upgrade it'' to the new hook documented in the above references and [TracWorkflow#Howtocombinethetracopt.ticket.commit_updaterwiththetestingworkflow here], as the old hook will not work with anything else than the default repository and even for this case, it won't trigger the appropriate notifications. 
    118194 
    119 ===== Authz permission checking ===== 
    120 The authz permission checking has been migrated to a fine-grained permission policy. If you use authz permissions (aka `[trac] authz_file` and `authz_module_name`), you must add `AuthzSourcePolicy` in front of your permission policies in `[trac] permission_policies`. You must also remove `BROWSER_VIEW`, `CHANGESET_VIEW`, `FILE_VIEW` and `LOG_VIEW` from your global permissions (with `trac-admin $ENV permission remove` or the "Permissions" admin panel). 
    121  
    122 ===== Microsecond timestamps ===== 
    123 All timestamps in database tables (except the `session` table) have been changed from "seconds since epoch" to "microseconds since epoch" values. This change should be transparent to most users, except for custom reports. If any of your reports use date/time columns in calculations (e.g. to pass them to `datetime()`), you must divide the values retrieved from the database by 1'000'000. Similarly, if a report provides a calculated value to be displayed as a date/time (i.e. with a column named "time", "datetime", "changetime", "date", "created" or "modified"), you must provide a microsecond timestamp, that is, multiply your previous calculation with 1'000'000. 
    124  
    125 ==== Upgrading from Trac 0.10 to Trac 0.11 ==== 
    126 ===== Site Templates and Styles ===== 
     195===== Authz permission checking 
     196 
     197The authz permission checking has been migrated to a fine-grained permission policy. If you use authz permissions (aka `[trac] authz_file` and `authz_module_name`), you must add `AuthzSourcePolicy` in front of your permission policies in `[trac] permission_policies`. You must also remove `BROWSER_VIEW`, `CHANGESET_VIEW`, `FILE_VIEW` and `LOG_VIEW` from your global permissions with `trac-admin $ENV permission remove` or the "Permissions" admin panel. 
     198 
     199===== Microsecond timestamps 
     200 
     201All timestamps in database tables, except the `session` table, have been changed from "seconds since epoch" to "microseconds since epoch" values. This change should be transparent to most users, except for custom reports. If any of your reports use date/time columns in calculations (e.g. to pass them to `datetime()`), you must divide the values retrieved from the database by 1'000'000. Similarly, if a report provides a calculated value to be displayed as a date/time (i.e. with a column named "time", "datetime", "changetime", "date", "created" or "modified"), you must provide a microsecond timestamp, that is, multiply your previous calculation with 1'000'000. 
     202 
     203==== Upgrading from Trac 0.10 to Trac 0.11 
     204 
     205===== Site Templates and Styles 
     206 
    127207The templating engine has changed in 0.11 to Genshi, please look at TracInterfaceCustomization for more information. 
    128208 
    129 If you are using custom CSS styles or modified templates in the `templates` directory of the TracEnvironment, you will need to convert them to the Genshi way of doing things. To continue to use your style sheet, follow the instructions at TracInterfaceCustomization#SiteAppearance. 
    130  
    131 ===== Trac Macros, Plugins ===== 
    132 The Trac macros will need to be adapted, as the old-style wiki-macros are not supported anymore (due to the drop of [trac:ClearSilver] and the HDF); they need to be converted to the new-style macros, see WikiMacros. When they are converted to the new style, they need to be placed into the plugins directory instead and not wiki-macros, which is no longer scanned for macros or plugins. 
    133  
    134 ===== For FCGI/WSGI/CGI users ===== 
     209If you are using custom CSS or modified templates in the `templates` directory of the TracEnvironment, you will need to convert them to the Genshi way of doing things. To continue to use your style sheet, follow the instructions at TracInterfaceCustomization#SiteAppearance. 
     210 
     211===== Trac Macros, Plugins 
     212 
     213The Trac macros will need to be adapted, as the old-style wiki-macros are not supported anymore due to the drop of [trac:ClearSilver] and the HDF. They need to be converted to the new-style macros, see WikiMacros. When they are converted to the new style, they need to be placed into the plugins directory instead and not wiki-macros, which is no longer scanned for macros or plugins. 
     214 
     215===== For FCGI/WSGI/CGI users 
     216 
    135217For those who run Trac under the CGI environment, run this command in order to obtain the trac.*gi file: 
    136 {{{ 
     218{{{#!sh 
    137219trac-admin /path/to/env deploy /deploy/directory/path 
    138220}}} 
    … …  
    140222This will create a deploy directory with the following two subdirectories: `cgi-bin` and `htdocs`. Then update your Apache configuration file `httpd.conf` with this new `trac.cgi` location and `htdocs` location. 
    141223 
    142 ===== Web Admin plugin integrated ===== 
    143 If you had the webadmin plugin installed, you can uninstall it as it is part of the Trac code base since 0.11. 
    144  
    145 === 7. Restart the Web Server === #RestarttheWebServer 
     224===== Web Admin plugin integrated 
     225 
     226If you had the [trac:WebAdmin] plugin installed, you can uninstall it as it is part of the Trac code base since 0.11. 
     227 
     228===== New Default Configurable Workflow 
     229 
     230When you run `trac-admin <env> upgrade`, your `trac.ini` will be modified to include a `[ticket-workflow]` section. The workflow configured in this case is the original workflow, so that ticket actions will behave like they did in 0.10: 
     231 
     232{{{#!Workflow width=500 height=240 
     233leave = * -> * 
     234leave.operations = leave_status 
     235leave.default = 1 
     236accept = new -> assigned 
     237accept.permissions = TICKET_MODIFY 
     238accept.operations = set_owner_to_self 
     239resolve = new,assigned,reopened -> closed 
     240resolve.permissions = TICKET_MODIFY 
     241resolve.operations = set_resolution 
     242reassign = new,assigned,reopened -> new 
     243reassign.permissions = TICKET_MODIFY 
     244reassign.operations = set_owner 
     245reopen = closed -> reopened 
     246reopen.permissions = TICKET_CREATE 
     247reopen.operations = del_resolution 
     248}}} 
     249 
     250There are some significant caveats in this, such as accepting a ticket sets it to 'assigned' state, and assigning a ticket sets it to 'new' state. So you will probably want to migrate to "basic" workflow; [trac:source:trunk/contrib/workflow/migrate_original_to_basic.py contrib/workflow/migrate_original_to_basic.py] may be helpful. See TracWorkflow for a detailed description of the new basic workflow. 
     251 
     252=== 7. Restart the Web Server #RestarttheWebServer 
    146253 
    147254If you are not running [wiki:TracCgi CGI], reload the new Trac code by restarting your web server. 
    148255 
    149 == Known Issues == 
    150  
    151 Things you should pay attention to, while upgrading. 
     256== Known Issues 
    152257 
    153258=== Customized Templates 
    154259 
    155 Trac supports customization of its Genshi templates by placing copies of the templates in the `<env>/templates` folder of your [TracEnvironment environment] or in a common location specified in the [[TracIni#GlobalConfiguration| [inherit] templates_dir]] configuration setting. If you choose to do so, be wary that you will need to repeat your changes manually on a copy of the new templates when you upgrade to a new release of Trac (even a minor one), as the templates will likely evolve. So keep a diff around ;-) 
    156  
    157 The preferred way to perform TracInterfaceCustomization is to write a custom plugin doing an appropriate `ITemplateStreamFilter` transformation, as this is more robust in case of changes: we usually won't modify element `id`s or change CSS `class`es, and if we have to do so, this will be documented in the TracDev/ApiChanges pages. 
    158  
    159 === !ZipImportError === 
    160  
    161 Due to internal caching of zipped packages,  whenever the content of the packages change on disk, the in-memory zip index will no longer match and you'll get irrecoverable !ZipImportError errors. Better anticipate and bring your server down for maintenance before upgrading. 
     260Trac supports customization of its Genshi templates by placing copies of the templates in the `<env>/templates` folder of your [TracEnvironment environment] or in a common location specified in the [[TracIni#GlobalConfiguration| [inherit] templates_dir]] configuration setting. If you choose to do so, be aware that you will need to repeat your changes manually on a copy of the new templates when you upgrade to a new release of Trac (even a minor one), as the templates will likely evolve. So keep a diff around. 
     261 
     262The preferred way to perform TracInterfaceCustomization is to write a custom plugin doing an appropriate `ITemplateStreamFilter` transformation, as this is more robust in case of changes: we usually won't modify element `id`s or change CSS `class`es, and if we have to do so, this will be documented in the [trac:TracDev/ApiChanges] pages. 
     263 
     264=== !ZipImportError 
     265 
     266Due to internal caching of zipped packages, whenever the content of the packages change on disk, the in-memory zip index will no longer match and you'll get irrecoverable !ZipImportError errors. Better anticipate and bring your server down for maintenance before upgrading. 
    162267See [trac:#7014] for details. 
    163268 
    164 === Wiki Upgrade === 
     269=== Wiki Upgrade 
     270 
    165271`trac-admin` will not delete or remove default wiki pages that were present in a previous version but are no longer in the new version. 
    166272 
    167 === Trac database upgrade === 
    168  
    169 A known issue in some versions of PySqlite (2.5.2-2.5.4) prevents the trac-admin upgrade script from successfully upgrading the database format. It is advised to use either a newer or older version of the sqlite python bindings to avoid this error. For more details see ticket [trac:#9434]. 
    170  
    171 === parent dir === 
    172 If you use a trac parent env configuration and one of the plugins in one child does not work, none of the children work. 
     273=== Trac database upgrade 
     274 
     275A known issue in some versions of [trac:PySqlite] (2.5.2-2.5.4) prevents the trac-admin upgrade script from successfully upgrading the database format. It is advised to use either a newer or older version of the sqlite python bindings to avoid this error. For more details see ticket [trac:#9434]. 
     276 
     277=== Parent dir 
     278 
     279If you use a Trac parent env configuration and one of the plugins in one child does not work, none of the children will work. 
    173280 
    174281== Related topics 
    175282 
    176 === Upgrading Python === 
    177  
    178 Upgrading Python to a newer version will require reinstallation of Python packages: Trac of course; also [http://pypi.python.org/pypi/setuptools easy_install], if you've been using that.  Assuming you're using Subversion, you'll also need to upgrade the Python bindings for svn. 
    179  
    180 ==== Windows and Python 2.6 ==== 
    181  
    182 If you've been using !CollabNet's Subversion package, you may need to uninstall that in favor of [http://alagazam.net/ Alagazam], which has the Python bindings readily available (see TracSubversion).  The good news is, that works with no tweaking. 
    183  
    184 === Changing Database Backend === 
    185 ==== SQLite to PostgreSQL ==== 
    186  
    187 The [http://trac-hacks.org/wiki/SqliteToPgScript sqlite2pg] script on [http://trac-hacks.org trac-hacks.org] has been written to assist in migrating a SQLite database to a PostgreSQL database 
    188  
    189 === Upgrading from older versions of Trac === #OlderVersions 
     283=== Upgrading Python 
     284 
     285Upgrading Python to a newer version will require reinstallation of Python packages: Trac itself of course, but also [http://pypi.python.org/pypi/setuptools easy_install], if you've been using that. If you are using Subversion, you'll also need to upgrade the Python bindings for svn. 
     286 
     287==== Windows and Python 2.6 
     288 
     289If you've been using !CollabNet's Subversion package, you may need to uninstall that in favor of [http://alagazam.net/ Alagazam], which has the Python bindings readily available, see [trac:TracSubversion]. That package works without tweaking. 
     290 
     291=== Changing Database Backend 
     292 
     293The [https://trac-hacks.org/wiki/TracMigratePlugin TracMigratePlugin] on [https://trac-hacks.org trac-hacks.org] has been written to assist in migrating between SQLite, MySQL and PostgreSQL databases. 
     294 
     295=== Upgrading from older versions of Trac #OlderVersions 
    190296 
    191297For upgrades from versions older than Trac 0.10, refer first to [trac:wiki:0.10/TracUpgrade#SpecificVersions].