diff --git a/state/indexer/sink/psql/psql.go b/state/indexer/sink/psql/psql.go
index 0e66d6117..94ae4cb93 100644
--- a/state/indexer/sink/psql/psql.go
+++ b/state/indexer/sink/psql/psql.go
@@ -50,7 +50,9 @@ func (es *EventSink) IndexBlockEvents(h types.EventDataNewBlockHeader) error {
 	sqlStmt := sq.
 		Insert(TableEventBlock).
 		Columns("key", "value", "height", "type", "created_at", "chain_id").
-		PlaceholderFormat(sq.Dollar)
+		PlaceholderFormat(sq.Dollar).
+		Suffix("ON CONFLICT (key,height)").
+		Suffix("DO NOTHING")
 
 	ts := time.Now()
 	// index the reserved block height index
@@ -83,12 +85,16 @@ func (es *EventSink) IndexTxEvents(txr []*abci.TxResult) error {
 		Columns("tx_result", "created_at").
 		PlaceholderFormat(sq.Dollar).
 		RunWith(es.store).
+		Suffix("ON CONFLICT (tx_result)").
+		Suffix("DO NOTHING").
 		Suffix("RETURNING \"id\"")
 
 	sqlStmtEvents := sq.
 		Insert(TableEventTx).
 		Columns("key", "value", "height", "hash", "tx_result_id", "created_at", "chain_id").
-		PlaceholderFormat(sq.Dollar)
+		PlaceholderFormat(sq.Dollar).
+		Suffix("ON CONFLICT (key,hash)").
+		Suffix("DO NOTHING")
 
 	ts := time.Now()
 	for _, tx := range txr {
@@ -100,17 +106,24 @@ func (es *EventSink) IndexTxEvents(txr []*abci.TxResult) error {
 		sqlStmtTxResult = sqlStmtTxResult.Values(txBz, ts)
 
 		// execute sqlStmtTxResult db query and retrieve the txid
-		err = sqlStmtTxResult.QueryRow().Scan(&txid)
+		r, err := sqlStmtTxResult.Query()
 		if err != nil {
 			return err
 		}
 
+		if !r.Next() {
+			return nil
+		}
+
+		if err := r.Scan(&txid); err != nil {
+			return err
+		}
+
 		// index the reserved height and hash indices
 		hash := fmt.Sprintf("%X", types.Tx(tx.Tx).Hash())
 
 		sqlStmtEvents = sqlStmtEvents.Values(types.TxHashKey, hash, tx.Height, hash, txid, ts, es.chainID)
 		sqlStmtEvents = sqlStmtEvents.Values(types.TxHeightKey, fmt.Sprint(tx.Height), tx.Height, hash, txid, ts, es.chainID)
-
 		for _, event := range tx.Result.Events {
 			// only index events with a non-empty type
 			if len(event.Type) == 0 {
diff --git a/state/indexer/sink/psql/psql_test.go b/state/indexer/sink/psql/psql_test.go
index 591d23edd..0c3cf81d0 100644
--- a/state/indexer/sink/psql/psql_test.go
+++ b/state/indexer/sink/psql/psql_test.go
@@ -72,6 +72,11 @@ func TestBlockFuncs(t *testing.T) {
 	assert.Equal(t, errors.New("block search is not supported via the postgres event sink"), err)
 
 	require.NoError(t, verifyTimeStamp(TableEventBlock))
+
+	// try to insert the duplicate block events.
+	err = indexer.IndexBlockEvents(getTestBlockHeader())
+	require.NoError(t, err)
+
 	require.NoError(t, teardown(t, pool))
 }
 
@@ -104,6 +109,10 @@ func TestTxFuncs(t *testing.T) {
 	assert.Nil(t, r2)
 	assert.Equal(t, errors.New("tx search is not supported via the postgres event sink"), err)
 
+	// try to insert the duplicate tx events.
+	err = indexer.IndexTxEvents([]*abci.TxResult{txResult})
+	require.NoError(t, err)
+
 	assert.Nil(t, teardown(t, pool))
 }
 
diff --git a/state/indexer/sink/psql/schema.sql b/state/indexer/sink/psql/schema.sql
index 36e7327cc..0be9bdfa8 100644
--- a/state/indexer/sink/psql/schema.sql
+++ b/state/indexer/sink/psql/schema.sql
@@ -6,12 +6,14 @@ CREATE TABLE block_events (
     height INTEGER NOT NULL,
     type block_event_type,
     created_at TIMESTAMPTZ NOT NULL,
-    chain_id VARCHAR NOT NULL
+    chain_id VARCHAR NOT NULL,
+    UNIQUE (key, height)
 );
 CREATE TABLE tx_results (
     id SERIAL PRIMARY KEY,
     tx_result BYTEA NOT NULL,
-    created_at TIMESTAMPTZ NOT NULL
+    created_at TIMESTAMPTZ NOT NULL,
+    UNIQUE (tx_result)
 );
 CREATE TABLE tx_events (
     id SERIAL PRIMARY KEY,
@@ -22,6 +24,7 @@ CREATE TABLE tx_events (
     tx_result_id SERIAL,
     created_at TIMESTAMPTZ NOT NULL,
     chain_id VARCHAR NOT NULL,
+    UNIQUE (hash, key),
     FOREIGN KEY (tx_result_id)
         REFERENCES tx_results(id)
         ON DELETE CASCADE