To support global autoblocks, we will (at least) need to modify the globalblocks table to add columns to:

1. Indicate whether a block should cause autoblocks
2. Whether a block is an autoblock
3. The parent block for an autoblock

To do this I propose that we add two columns, where:

• gb_enable_autoblock holds whether a block can cause autoblocks (for point 1)
• gb_autoblock_parent_id holds the parent block ID if the block is an autoblock (for point 3) and null if the block is not an autoblock (for point 2)

We may at a later stage need to perform further schema changes. For example, if we determine that the collateral caused by global autoblocks is too large we may wish to limit where the autoblock applies (i.e. just to the wikis that the target of the parent block have edited). However, these should be required even if we don't use IP addresses as the target of autoblocks (for example cookie-based autoblocks).

Acceptance criteria

• Add gb_enable_autoblock and gb_autoblock_parent_id to the globalblocks table