private void accept(String modelName, ModelColumn modelColumn) throws IllegalStateException {
            final int idx = modelColumn.getBanyanDBExtension().getShardingKeyIdx();
            while (idx + 1 > keys.size()) {
                keys.add(null);
            }
            ModelColumn exist = keys.get(idx);
            if (exist != null) {
                throw new IllegalStateException(
                    modelName + "'s "
                        + "Column [" + exist.getColumnName() + "] and column [" + modelColumn.getColumnName()
                        + " are conflicting with sharding key index=" + modelColumn.getBanyanDBExtension()
                                                                                   .getShardingKeyIdx());
            }
            keys.set(idx, modelColumn);
        }
@throws IllegalStateException if sharding key indices are conflicting.
oap-server/server-core/src/main/java/org/apache/skywalking/oap/server/core/storage/model/StorageModels.java