22 calls to db_drop_index()

block_update_7002 in modules/block/block.install
Rename {blocks} table to {block}, {blocks_roles} to {block_role} and {boxes} to {block_custom}.
comment_update_7003 in modules/comment/comment.install
Split {comment}.timestamp into 'created' and 'changed', improve indexing on {comment}.
comment_update_7008 in modules/comment/comment.install
Update database to match Drupal 7 schema.
contact_update_7003 in modules/contact/contact.install
Change the weight column to normal int.
field_sql_storage_field_storage_update_field in modules/field/modules/field_sql_storage/field_sql_storage.module
Implements hook_field_storage_update_field().
forum_update_7000 in modules/forum/forum.install
Add new index to forum table.
forum_update_7002 in modules/forum/forum.install
Add new index to forum_index table.
forum_update_7003 in modules/forum/forum.install
Rename field to 'taxonomy_forums'.
locale_update_7000 in modules/locale/locale.install
Add context field index and allow longer location.
node_update_7002 in modules/node/node.install
Extend the node_promote_status index to include all fields required for the node page query.
node_update_7011 in modules/node/node.install
Update the database from Drupal 6 to match the schema.
node_update_7016 in modules/node/node.install
Change {history}.nid to an unsigned int in order to match {node}.nid.
search_update_7000 in modules/search/search.install
Replace unique keys in 'search_dataset' and 'search_index' by primary keys.
system_update_7018 in modules/system/system.install
Shorten the {system}.type column and modify indexes.
system_update_7032 in modules/system/system.install
Alter field hostname to identifier in the {flood} table.
system_update_7042 in modules/system/system.install
Upgrade the {url_alias} table and create a cache bin for path aliases.
system_update_7062 in modules/system/system.install
Replace 'system_list' index with 'bootstrap' index on {system}.
system_update_7071 in modules/system/system.install
Add index missed during upgrade, and fix field default.
taxonomy_update_7008 in modules/taxonomy/taxonomy.install
Change the weight columns to normal int.
update_fix_d7_requirements in includes/update.inc
Perform Drupal 6.x to 7.x updates that are required for update.php to function properly.
user_update_7005 in modules/user/user.install
Changes the users table to allow longer e-mail addresses.
user_update_7020 in modules/user/user.install
Add changed field to users table.

Buggy or inaccurate documentation? Please file an issue. Need support? Need help programming? Connect with the Drupal community.