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refactoring of virtual columns

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This commit is contained in:
Anton Popov 2024-02-21 17:24:12 +00:00
parent 3d57237fe8
commit 6656cdb9fb
1 changed files with 12 additions and 17 deletions
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29
src/Storages/MergeTree/MergeTreeBlockReadUtils.cpp
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@ -7,6 +7,7 @@
#include <Common/checkStackSize.h>
#include <Common/typeid_cast.h>
#include "Storages/ColumnsDescription.h"
#include "Storages/MergeTreeVirtualColumns.h"
#include <Storages/MergeTree/MergeTreeSelectProcessor.h>
#include <Columns/ColumnConst.h>
#include <IO/WriteBufferFromString.h>
@ -107,21 +108,14 @@ NameSet injectRequiredColumns(
auto options = GetColumnsOptions(GetColumnsOptions::AllPhysical)
.withExtendedObjects()
.withVirtuals(VirtualsKind::Persistent)
.withVirtuals()
.withSubcolumns(with_subcolumns);
auto virtuals_options = GetColumnsOptions(GetColumnsOptions::None).withVirtuals();
for (size_t i = 0; i < columns.size(); ++i)
{
/// We are going to fetch physical columns and system columns first
if (!storage_snapshot->tryGetColumn(options, columns[i]))
{
if (storage_snapshot->tryGetColumn(virtuals_options, columns[i]))
continue;
else
throw Exception(ErrorCodes::NO_SUCH_COLUMN_IN_TABLE, "There is no column or subcolumn {} in table", columns[i]);
}
throw Exception(ErrorCodes::NO_SUCH_COLUMN_IN_TABLE, "There is no column or subcolumn {} in table", columns[i]);
have_at_least_one_physical_column |= injectRequiredColumnsRecursively(
columns[i], storage_snapshot, alter_conversions,
@ -285,12 +279,20 @@ MergeTreeReadTaskColumns getReadTaskColumns(
.withVirtuals()
.withSubcolumns(with_subcolumns);
bool has_part_offset = std::find(required_columns.begin(), required_columns.end(), "_part_offset") != required_columns.end();
static const NameSet columns_to_read_at_first_step = {"_part_offset", BlockOffsetColumn::name};
NameSet columns_from_previous_steps;
auto add_step = [&](const PrewhereExprStep & step)
{
Names step_column_names;
if (columns_from_previous_steps.empty())
{
for (const auto & required_column : required_columns)
if (columns_to_read_at_first_step.contains(required_column))
step_column_names.push_back(required_column);
}
/// Computation results from previous steps might be used in the current step as well. In such a case these
/// computed columns will be present in the current step inputs. They don't need to be read from the disk so
/// exclude them from the list of columns to read. This filtering must be done before injecting required
@ -301,13 +303,6 @@ MergeTreeReadTaskColumns getReadTaskColumns(
if (!columns_from_previous_steps.contains(name))
step_column_names.push_back(name);
/// Make sure _part_offset is read in STEP 0
if (columns_from_previous_steps.empty() && has_part_offset)
{
if (std::find(step_column_names.begin(), step_column_names.end(), "_part_offset") == step_column_names.end())
step_column_names.push_back("_part_offset");
}
if (!step_column_names.empty())
injectRequiredColumns(
data_part_info_for_reader, storage_snapshot,