Document schema mapping mechanism

[mshustov]

THe docs page doesn't mention built-in logic to update schema mappings

clickhouse-kafka-connect/src/main/java/com/clickhouse/kafka/connect/sink/db/ClickHouseWriter.java

Lines 819 to 832 in 23bdde8

	protected void doInsertRawBinary(List<Record> records, Table table, QueryIdentifier queryId, boolean supportDefaults, boolean retry) throws IOException, ExecutionException, InterruptedException {
	try {
	if (chc.isUseClientV2()) {
	doInsertRawBinaryV2(records, table, queryId, supportDefaults);
	} else {
	doInsertRawBinaryV1(records, table, queryId, supportDefaults);
	}
	} catch (ServerException e) {
	LOGGER.error("Error inserting records can cause by schema changes", e);
	if (e.getCode() == 33 && retry == true) {
	LOGGER.error("Error code 33: ClickHouse server error. Trying to update table mapping.");
	updateMapping(table.getDatabase());
	Table tableTmp = getTable(table.getDatabase(), table.getName());
	doInsertRawBinary(records, tableTmp, queryId, tableTmp.hasDefaults(), false);