When a retroactive autoblocks are applied to users that are blocked nearly at the same time, the retroactive autoblock code attempts to retroactively autoblock the same IP. This fails due to database deadlocks.
Error
1.43 onwards:
[{reqId}] {exception_url} RuntimeException: Duplicate block_target rows detected: 1983002,1983009,1983016
[{reqId}] {exception_url} Wikimedia\Rdbms\DBQueryError: Error 1213: Deadlock found when trying to get lock; try restarting transaction Function: MediaWiki\Block\DatabaseBlockStore::acquireTarget Query: INSERT INTO `block_target` (bt_address,bt_user,bt_u
from /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1172) #0 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1045): MediaWiki\Block\DatabaseBlockStore->acquireTarget(MediaWiki\Block\DatabaseBlock, Wikimedia\Rdbms\DBConnRef, integer) #1 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1000): MediaWiki\Block\DatabaseBlockStore->attemptInsert(MediaWiki\Block\DatabaseBlock, Wikimedia\Rdbms\DBConnRef, integer) #2 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1627): MediaWiki\Block\DatabaseBlockStore->insertBlock(MediaWiki\Block\DatabaseBlock) #3 /srv/mediawiki/php-1.43.0-wmf.14/extensions/CheckUser/src/HookHandler/PerformRetroactiveAutoblockHandler.php(98): MediaWiki\Block\DatabaseBlockStore->doAutoblock(MediaWiki\Block\DatabaseBlock, string) #4 /srv/mediawiki/php-1.43.0-wmf.14/includes/HookContainer/HookContainer.php(159): MediaWiki\CheckUser\HookHandler\PerformRetroactiveAutoblockHandler->onPerformRetroactiveAutoblock(MediaWiki\Block\DatabaseBlock, array) #5 /srv/mediawiki/php-1.43.0-wmf.14/includes/HookContainer/HookRunner.php(3075): MediaWiki\HookContainer\HookContainer->run(string, array) #6 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1486): MediaWiki\HookContainer\HookRunner->onPerformRetroactiveAutoblock(MediaWiki\Block\DatabaseBlock, array) #7 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1012): MediaWiki\Block\DatabaseBlockStore->doRetroactiveAutoblock(MediaWiki\Block\DatabaseBlock) #8 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/BlockUser.php(596): MediaWiki\Block\DatabaseBlockStore->insertBlock(MediaWiki\Block\DatabaseBlock) #9 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/BlockUser.php(533): MediaWiki\Block\BlockUser->placeBlockInternal(boolean) #10 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/BlockUser.php(459): MediaWiki\Block\BlockUser->placeBlockUnsafe(boolean) #11 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiBlock.php(178): MediaWiki\Block\BlockUser->placeBlock(boolean) #12 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiMain.php(1953): ApiBlock->execute() #13 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiMain.php(929): ApiMain->executeAction() #14 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiMain.php(900): ApiMain->executeActionWithErrorHandling() #15 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiEntryPoint.php(158): ApiMain->execute() #16 /srv/mediawiki/php-1.43.0-wmf.14/includes/MediaWikiEntryPoint.php(200): MediaWiki\Api\ApiEntryPoint->execute() #17 /srv/mediawiki/php-1.43.0-wmf.14/api.php(44): MediaWiki\MediaWikiEntryPoint->run() #18 /srv/mediawiki/w/api.php(3): require(string) #19 {main}
from /srv/mediawiki/php-1.43.0-wmf.14/includes/libs/rdbms/database/Database.php(1194) #0 /srv/mediawiki/php-1.43.0-wmf.14/includes/libs/rdbms/database/Database.php(1178): Wikimedia\Rdbms\Database->getQueryException(string, integer, string, string) #1 /srv/mediawiki/php-1.43.0-wmf.14/includes/libs/rdbms/database/Database.php(1152): Wikimedia\Rdbms\Database->getQueryExceptionAndLog(string, integer, string, string) #2 /srv/mediawiki/php-1.43.0-wmf.14/includes/libs/rdbms/database/Database.php(643): Wikimedia\Rdbms\Database->reportQueryError(string, integer, string, string, boolean) #3 /srv/mediawiki/php-1.43.0-wmf.14/includes/libs/rdbms/database/Database.php(1472): Wikimedia\Rdbms\Database->query(Wikimedia\Rdbms\Query, string) #4 /srv/mediawiki/php-1.43.0-wmf.14/includes/libs/rdbms/database/DBConnRef.php(127): Wikimedia\Rdbms\Database->insert(string, array, string, array) #5 /srv/mediawiki/php-1.43.0-wmf.14/includes/libs/rdbms/database/DBConnRef.php(407): Wikimedia\Rdbms\DBConnRef->__call(string, array) #6 /srv/mediawiki/php-1.43.0-wmf.14/includes/libs/rdbms/querybuilder/InsertQueryBuilder.php(343): Wikimedia\Rdbms\DBConnRef->insert(string, array, string, array) #7 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1201): Wikimedia\Rdbms\InsertQueryBuilder->execute() #8 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1045): MediaWiki\Block\DatabaseBlockStore->acquireTarget(MediaWiki\Block\DatabaseBlock, Wikimedia\Rdbms\DBConnRef, integer) #9 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1000): MediaWiki\Block\DatabaseBlockStore->attemptInsert(MediaWiki\Block\DatabaseBlock, Wikimedia\Rdbms\DBConnRef, integer) #10 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1627): MediaWiki\Block\DatabaseBlockStore->insertBlock(MediaWiki\Block\DatabaseBlock) #11 /srv/mediawiki/php-1.43.0-wmf.14/extensions/CheckUser/src/HookHandler/PerformRetroactiveAutoblockHandler.php(98): MediaWiki\Block\DatabaseBlockStore->doAutoblock(MediaWiki\Block\DatabaseBlock, string) #12 /srv/mediawiki/php-1.43.0-wmf.14/includes/HookContainer/HookContainer.php(159): MediaWiki\CheckUser\HookHandler\PerformRetroactiveAutoblockHandler->onPerformRetroactiveAutoblock(MediaWiki\Block\DatabaseBlock, array) #13 /srv/mediawiki/php-1.43.0-wmf.14/includes/HookContainer/HookRunner.php(3075): MediaWiki\HookContainer\HookContainer->run(string, array) #14 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1486): MediaWiki\HookContainer\HookRunner->onPerformRetroactiveAutoblock(MediaWiki\Block\DatabaseBlock, array) #15 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/DatabaseBlockStore.php(1012): MediaWiki\Block\DatabaseBlockStore->doRetroactiveAutoblock(MediaWiki\Block\DatabaseBlock) #16 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/BlockUser.php(596): MediaWiki\Block\DatabaseBlockStore->insertBlock(MediaWiki\Block\DatabaseBlock) #17 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/BlockUser.php(533): MediaWiki\Block\BlockUser->placeBlockInternal(boolean) #18 /srv/mediawiki/php-1.43.0-wmf.14/includes/block/BlockUser.php(459): MediaWiki\Block\BlockUser->placeBlockUnsafe(boolean) #19 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiBlock.php(178): MediaWiki\Block\BlockUser->placeBlock(boolean) #20 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiMain.php(1953): ApiBlock->execute() #21 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiMain.php(929): ApiMain->executeAction() #22 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiMain.php(900): ApiMain->executeActionWithErrorHandling() #23 /srv/mediawiki/php-1.43.0-wmf.14/includes/api/ApiEntryPoint.php(158): ApiMain->execute() #24 /srv/mediawiki/php-1.43.0-wmf.14/includes/MediaWikiEntryPoint.php(200): MediaWiki\Api\ApiEntryPoint->execute() #25 /srv/mediawiki/php-1.43.0-wmf.14/api.php(44): MediaWiki\MediaWikiEntryPoint->run() #26 /srv/mediawiki/w/api.php(3): require(string) #27 {main}
Pre MW 1.43:
Error 1213: Deadlock found when trying to get lock; try restarting transaction (10.64.16.101) Function: MediaWiki\Block\DatabaseBlockStore::insertBlock Query: INSERT IGNORE INTO `ipblocks` (ipb_address,ipb_user,ipb_timestamp,ipb_auto,ipb_anon_only,ipb_create_account,ipb_enable_autoblock,ipb_expiry,ipb_range_start,ipb_range_end,ipb_deleted,ipb_block_email,ipb_allow_usertalk,ipb_parent_block_id,ipb_sitewide,ipb_reason_id,ipb_by_actor) VALUES (<redacted>)