1. 12 Nov, 2017 1 commit
  2. 02 Oct, 2017 1 commit
    • Andy Schmitz's avatar
      Make IdsToBigints (mostly!) non-blocking (#5088) · 97c02c33
      Andy Schmitz authored
      * Make IdsToBigints (mostly!) non-blocking
      
      This pulls in GitLab's MigrationHelpers, which include code to make
      column changes in ways that Postgres can do without locking. In general,
      this involves creating a new column, adding an index and any foreign
      keys as appropriate, adding a trigger to keep it populated alongside
      the old column, and then progressively copying data over to the new
      column, before removing the old column and replacing it with the new
      one.
      
      A few changes to GitLab's MigrationHelpers were necessary:
      
      * Some changes were made to remove dependencies on other GitLab code.
      * We explicitly wait for index creation before forging ahead on column
        replacements.
      * We use different temporary column names, to avoid running into index
        name length limits.
      * We rename the generated indices back to what they "should" be after
        replacing columns.
      * We rename the generated foreign keys to use the new column names when
        we had to create them. (This allows the migration to be rolled back
        without incident.)
      
      # Big Scary Warning
      
      There are two things here that may trip up large instances:
      
      1. The change for tables' "id" columns is not concurrent. In
         particular, the stream_entries table may be big, and does not
         concurrently migrate its id column. (On the other hand, x_id type
         columns are all concurrent.)
      2. This migration will take a long time to run, *but it should not
         lock tables during that time* (with the exception of the "id"
         columns as described above). That means this should probably be run
         in `screen` or some other session that can be run for a long time.
         Notably, the migration will take *longer* than it would without
         these changes, but the website will still be responsive during that
         time.
      
      These changes were tested on a relatively large statuses table (256k
      entries), and the service remained responsive during the migration.
      Migrations both forward and backward were tested.
      
      * Rubocop fixes
      
      * MigrationHelpers: Support ID columns in some cases
      
      This doesn't work in cases where the ID column is referred to as a
      foreign key by another table.
      
      * MigrationHelpers: support foreign keys for ID cols
      
      Note that this does not yet support foreign keys on non-primary-key
      columns, but Mastodon also doesn't yet have any that we've needed to
      migrate.
      
      This means we can perform fully "concurrent" migrations to change ID
      column types, and the IdsToBigints migration can happen with effectively
      no downtime. (A few operations require a transaction, such as renaming
      columns or deleting them, but these transactions should not block for
      noticeable amounts of time.)
      
      The algorithm for generating foreign key names has changed with this,
      and therefore all of those changed in schema.rb.
      
      * Provide status, allow for interruptions
      
      The MigrationHelpers now allow restarting the rename of a column if it
      was interrupted, by removing the old "new column" and re-starting the
      process.
      
      Along with this, they now provide status updates on the changes which
      are happening, as well as indications about when the changes can be
      safely interrupted (when there are at least 10 seconds estimated to be
      left before copying data is complete).
      
      The IdsToBigints migration now also sorts the columns it migrates by
      size, starting with the largest tables. This should provide
      administrators a worst-case scenario estimate for the length of
      migrations: each successive change will get faster, giving admins a
      chance to abort early on if they need to run the migration later. The
      idea is that this does not force them to try to time interruptions
      between smaller migrations.
      
      * Fix column sorting in IdsToBigints
      
      Not a significant change, but it impacts the order of columns in the
      database and db/schema.rb.
      
      * Actually pause before IdsToBigints
      97c02c33
  3. 31 May, 2017 1 commit
    • Matt Jankowski's avatar
      Misc tidying and clean ups (#3445) · b25e42a7
      Matt Jankowski authored
      * Remove trailing whitespace in i18n mailers
      
      * Use query methods instead of #present? on AR attributes
      
      * Delegate Status#account_domain method
      
      * Delegate Mention #account_username and #account_acct methods
      b25e42a7
  4. 02 May, 2017 1 commit
    • yhirano's avatar
      annotate models (#2697) · 298796cc
      yhirano authored
      * add annotate to Gemfile
      
      * rails g annotate:install
      
      * configure annotate_models
      
      * add schema info to models
      
      * fix rubocop to add frozen_string_literal
      298796cc
  5. 04 Apr, 2017 1 commit
  6. 21 Nov, 2016 1 commit
  7. 15 Nov, 2016 1 commit
  8. 17 Aug, 2016 1 commit
  9. 28 Feb, 2016 1 commit
  10. 24 Feb, 2016 1 commit