I have a batch which I need to use in order to update a table. This batch is getting fill by an algorithm that I can't change. But it is doing something like this:
String updateFilter = "UPDATE payload_roas SET filtered = TRUE WHERE asn = ? AND prefix= ? AND max_length = ?";
PreparedStatement ps= connection.prepareStatement(updateFilter);
for(int i = 0; i < roas.size(); i++) {
roa = roas.get(i);
ps.setLong(1, roa.getAsn());
ps.setObject(2, roa.getPrefix(), OTHER);
ps.setInt(3, roa.getMax_length());
ps.setBoolean(4, roa.isWhitelist);
ps.setBoolean(5, roa.isFilter);
ps.addBatch();
}
This batch is quite big ~50K entries.So no surprise that it takes a lot of time when I'm doing executeBatch. However this ps contains lots of duplicates which means it is doing multiple redundant updates. Is there any way to perform a distinct operation on this batch in order to remove this duplicates?
You can try to do something like this:
String updateFilter = "UPDATE payload_roas SET filtered = TRUE WHERE asn = ? AND prefix= ? AND max_length = ?";
PreparedStatement ps= connection.prepareStatement(updateFilter);
HashSet<String> hashKeys = new HashSet<>();
for(int i = 0; i < roas.size(); i++) {
roa = roas.get(i);
String key = roa.getAsn() + roa.getPrefix().toString() + roa.getMax_length() + roa.isWhitelist + roa.isFilter;
if (!hashKeys.contains(key)) {
hashKeys.add(key);
ps.setLong(1, roa.getAsn());
ps.setObject(2, roa.getPrefix(), OTHER);
ps.setInt(3, roa.getMax_length());
ps.setBoolean(4, roa.isWhitelist);
ps.setBoolean(5, roa.isFilter);
ps.addBatch();
}
}
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