1 files changed, 1 insertions, 0 deletions
diff --git a/synapse/storage/schema/transactions.sql b/synapse/storage/schema/transactions.sql
index 86f530d82a..2d30f99b06 100644
--- a/synapse/storage/schema/transactions.sql
+++ b/synapse/storage/schema/transactions.sql
@@ -42,6 +42,7 @@ CREATE INDEX IF NOT EXISTS sent_transaction_dest ON sent_transactions(destinatio
 CREATE INDEX IF NOT EXISTS sent_transaction_dest_referenced ON sent_transactions(
     destination
 );
+CREATE INDEX IF NOT EXISTS sent_transaction_txn_id ON sent_transactions(transaction_id);
 -- So that we can do an efficient look up of all transactions that have yet to be successfully
 -- sent.
 CREATE INDEX IF NOT EXISTS sent_transaction_sent ON sent_transactions(response_code);