@Override
	protected RecordIterator getPrimarySymbols(AddressSetView set, boolean forward)
			throws IOException {
		return new KeyToRecordIterator(symbolTable, new AddressIndexPrimaryKeyIterator(symbolTable,
			SYMBOL_PRIMARY_COL, addrMap, set, forward));
	}
SymbolDatabaseAdapter for version 3

This version added additional sparse columns to store optional data specific to certain
symbol types.  The adhoc string data column was eliminated.
Ghidra/Framework/SoftwareModeling/src/main/java/ghidra/program/database/symbol/SymbolDatabaseAdapterV4.java