Change DB engine for primary_xref

Workaround for “The total number of locks exceeds the lock table size” found when running xref pipeline

misc-scripts/xref_mapping/sql/table.sql

@@ -55,7 +55,7 @@ CREATE TABLE primary_xref (
 
   PRIMARY KEY (xref_id)
 
-) COLLATE=latin1_swedish_ci ENGINE=InnoDB;
+) COLLATE=latin1_swedish_ci ENGINE=MyISAM;
 
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