Manual:Suitability of tables for sharing
From Linux Web Expert
Some tables lend themselves better than others to being shared using $wgSharedTables.
| Table | Can be shared? | Comments |
|---|---|---|
| archive | <translate> No</translate> | ar_rev_id collisions |
| category | <translate> No</translate> | cat_title collisions |
| categorylinks | <translate> No</translate> | cl_from collisions |
| change_tag | <translate> No</translate> | ct_log_id collisions |
| comment | <translate> No</translate> | Houses comments linked to multiple unshareable tables. |
| externallinks | <translate> No</translate> | el_from collisions |
| filearchive | <translate> No</translate> | ? |
| image | <translate> No</translate> | To have a shared media repository, see $wgForeignFileRepos |
| imagelinks | <translate> No</translate> | il_from collisions |
| interwiki | <translate> Yes</translate> | The interwiki table contains mostly static data; it may be useful to share if you have many custom interwikis. |
| ipblocks | <translate> Yes</translate> | By sharing the ipblocks table, you can have "global blocks" so that a block on one wiki will block the user or IP on all other wikis using the shared database. There can be some minor issues when sharing the ipblocks table. Viz., the ipb_reason field is set as the "reason" on Special:Block when blocking a user. When a blocked user sees the "You are blocked" message, this is parsed as wikitext, and links are parsed on Special:BlockList, you will need to make sure when blocking a user that the message makes sense on all wikis. Also, block logs will not be shared. (You must also share your user table for shared ipblocks to work.)
Note that the comment table cannot be shared, which may cause issues with some blocking-related code, per phab:T214011. |
| iwlinks | <translate> No</translate> | iwl_from collisions |
| job | <translate> No</translate> | job_title collisions |
| l10n_cache | ? | ? |
| langlinks | <translate> No</translate> | ll_from collisions |
| linktarget | ? | ? |
| logging | <translate> No</translate> | log_page collisions |
| log_search | <translate> No</translate> | ls_value collisions |
| module_deps | ? | ? |
| objectcache | <translate> Yes</translate> | ? |
| oldimage | ? | ? |
| page | <translate> No</translate> | page_namespace and page_title collisions |
| pagelinks | <translate> No</translate> | pl_from collisions |
| page_props | <translate> No</translate> | pp_page collisions |
| page_restrictions | <translate> No</translate> | pr_page collisions |
| protected_titles | <translate> No</translate> | pt_namespace and pt_title collisions |
| querycache | <translate> No</translate> | qc_namespace and qc_title collisions |
| querycachetwo | <translate> No</translate> | qcc_namespace and qcc_title collisions |
| querycache_info | <translate> No</translate> | qc_type collisions |
| recentchanges | <translate> No</translate> | rc_cur_id collisions |
| redirect | <translate> No</translate> | rd_from collisions |
| revision | <translate> No</translate> | rev_page collisions |
| searchindex | <translate> No</translate> | si_page collisions |
| site_stats | <translate> Yes</translate> | The site_stats table could possibly be shared, to aggregate data over all your wikis. |
| tag_summary | <translate> No</translate> | ts_rc_id, ts_log_id, and ts_rev_id collisions |
| templatelinks | <translate> No</translate> | tl_from, tl_namespace and tl_title collisions |
| transcache | ? | ? |
| updatelog | ? | ? |
| uploadstash | ? | ? |
| user | <translate> Yes</translate> | A shared user table can be used to have multiple wikis that have shared user registrations, so that users need only sign up to one wiki. See Manual:Shared database. |
| user_former groups | <translate> Yes</translate> | You would need to share the user table as well, and presumably user_groups. |
| user_groups | <translate> Yes</translate> | Sharing the user_groups table will allow you to have global user groups. As with the block log, the user rights log is not shared. |
| user_newtalk | ? | ? |
| user_properties | <translate> Yes</translate> | By default, the user_properties table is included in the list of shared tables. |
| valid_tag | ? | ? |
| watchlist | <translate> No</translate> | wl_namespace and wl_title collisions |
