Method filterPartitionByTTL

src/MergeTreeCommon/MergeTreeMetaBase.cpp:2108–2202

}

void MergeTreeMetaBase::filterPartitionByTTL(std::vector<std::shared_ptr<MergeTreePartition>> & partition_list, time_t query_time) const
{
    if (canFilterPartitionByTTL())
    {
        const auto & metadata_snapshot = getInMemoryMetadataPtr();
        if (!metadata_snapshot->hasRowsTTL())
            return;

        /// make a copy of rows_ttl, we may rewrite it later.
        auto rows_ttl = metadata_snapshot->table_ttl.rows_ttl;

        /// Construct a block consists of partition keys then compute ttl values according to this block
        const auto & partition_key_sample = metadata_snapshot->getPartitionKey().sample_block;
        MutableColumns columns = partition_key_sample.cloneEmptyColumns();

        for (const auto & partition : partition_list)
        {
            /// This can happen when ALTER query is implemented improperly; finish ALTER query should bypass this check.
            if (columns.size() != partition->value.size())
                throw Exception(
                    ErrorCodes::LOGICAL_ERROR,
                    "Partition key columns definition missmatch between inmemory and metastore, this is a bug, expect block ({}), got values "
                    "({})\n",
                    partition_key_sample.dumpNames(),
                    fmt::join(partition->value, ", "));

            for (size_t i = 0; i < partition->value.size(); ++i)
                columns[i]->insert(partition->value[i]);
        }

        auto block = partition_key_sample.cloneWithColumns(std::move(columns));
        TTLDescription::tryRewriteTTLWithPartitionKey(rows_ttl, metadata_snapshot->columns, metadata_snapshot->partition_key, metadata_snapshot->primary_key, getContext());
        rows_ttl.expression->execute(block);

        // got the ttl values for each partition based on ttl expression
        const auto & ttl_values = block.getByName(rows_ttl.result_column);
        const IColumn * column = ttl_values.column.get();

        if (column->size() != partition_list.size())
            throw Exception("Calculated TTL column size cannot match input partitions column size.", ErrorCodes::LOGICAL_ERROR);

        if (query_time == 0)
            query_time = std::time(nullptr);

        std::vector<std::shared_ptr<MergeTreePartition>> filtered_result;

        if (column->isNullable())
            column = static_cast<const ColumnNullable *>(column)->getNestedColumnPtr().get();

        if (const ColumnUInt16 * column_date = typeid_cast<const ColumnUInt16 *>(column))
        {
            const auto & date_lut = DateLUT::serverTimezoneInstance();
            for (size_t index = 0; index < column->size(); index++)
            {
                auto ttl_value = date_lut.fromDayNum(DayNum(column_date->getElement(index)));
                if (ttl_value >= query_time)
                    filtered_result.push_back(partition_list[index]);
            }