MERGE INTO multiple statements at once Oracle SQL - sql

Question

I have a merge into statement as this :
private static final String UPSERT_STATEMENT = "MERGE INTO " + TABLE_NAME + " tbl1 " +
"USING (SELECT ? as KEY,? as DATA,? as LAST_MODIFIED_DATE FROM dual) tbl2 " +
"ON (tbl1.KEY= tbl2.KEY) " +
"WHEN MATCHED THEN UPDATE SET DATA = tbl2.DATA, LAST_MODIFIED_DATE = tbl2.LAST_MODIFIED_DATE " +
"WHEN NOT MATCHED THEN " +
"INSERT (DETAILS,KEY, DATA, CREATION_DATE, LAST_MODIFIED_DATE) " +
"VALUES (SEQ.NEXTVAL,tbl2.KEY, tbl2.DATA, tbl2.LAST_MODIFIED_DATE,tbl2.LAST_MODIFIED_DATE)";
This is the execution method:
public void mergeInto(final JavaRDD<Tuple2<Long, String>> rows) {
if (rows != null && !rows.isEmpty()) {
rows.foreachPartition((Iterator<Tuple2<Long, String>> iterator) -> {
JdbcTemplate jdbcTemplate = jdbcTemplateFactory.getJdbcTemplate();
LobCreator lobCreator = new DefaultLobHandler().getLobCreator();
while (iterator.hasNext()) {
Tuple2<Long, String> row = iterator.next();
String details = row._2();
Long key = row._1();
java.sql.Date lastModifiedDate = Date.valueOf(LocalDate.now());
Boolean isSuccess = jdbcTemplate.execute(UPSERT_STATEMENT, (PreparedStatementCallback<Boolean>) ps -> {
ps.setLong(1, key);
lobCreator.setBlobAsBytes(ps, 2, details.getBytes());
ps.setObject(3, lastModifiedDate);
return ps.execute();
});
System.out.println(row + "_" + isSuccess);
}
});
}
}
I need to upsert multiple of this statement inside of PLSQL, bulks of 10K if possible.
what is the efficient way to save time : execute 10K statements at once, or how to execute 10K statements in the same transaction?
how should I change the method for support it?
Thanks,
Me

Answer 1

the most efficient way would be one that bulk-loads your data into the database. In comparison to one-by-one uploads (as in your example), I'd expect performance gains of at least 1 or 2 orders of magnitude ("bigger" data means less to be gained by bulk-inserting).
you could use a technique as described in this answer to bulk-insert your records into a temporary table first and then perform a single merge statement using the temporary table.