On this Gerrit change, @Michael reported that running

php maintenance/run.php WikibaseQualityConstraints:ImportConstraintEntities.php

fails on a Wikibase with default settings, with an EntityContentTooBigException: On Wikidata, the maxSerializedEntitySize is 3000 (kibibytes), but by default it’s $wgMaxArticleSize, which in turn is only 2048 kiB. The serialized entity size is also checked during deserialization, so while ImportConstraintEntities removes statements, they can still cause the error:

		$wikidataEntityArray = json_decode( $wikidataEntitiesJson, true )['entities'][$wikidataEntityId];
		$wikidataEntity = $this->entityDeserializer->deserialize( $wikidataEntityArray ); // <-- EntityContentTooBigException thrown here

		$wikidataEntity->setId( null );

		if ( $wikidataEntity instanceof StatementListProvider ) {
			$wikidataEntity->getStatements()->clear();
		}
		// entity would *now* be small enough to fit in the local wiki (probably)

TODO: Check which entity is causing the error, and if it’s still too large without the statements. If not, then a relatively simple solution would be to unset( $wikidataEntityArray['claims'] ) before deserializing the entity.