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97f2a2213e
* Move some code outside dbms/src folder * Fix paths
129 lines
4.3 KiB
C++
129 lines
4.3 KiB
C++
#include <Storages/MergeTree/MergeTreeSelectProcessor.h>
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#include <Storages/MergeTree/MergeTreeBaseSelectProcessor.h>
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#include <Storages/MergeTree/IMergeTreeReader.h>
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namespace DB
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{
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namespace ErrorCodes
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{
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extern const int MEMORY_LIMIT_EXCEEDED;
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}
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MergeTreeSelectProcessor::MergeTreeSelectProcessor(
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const MergeTreeData & storage_,
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const MergeTreeData::DataPartPtr & owned_data_part_,
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UInt64 max_block_size_rows_,
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size_t preferred_block_size_bytes_,
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size_t preferred_max_column_in_block_size_bytes_,
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Names required_columns_,
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MarkRanges mark_ranges_,
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bool use_uncompressed_cache_,
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const PrewhereInfoPtr & prewhere_info_,
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bool check_columns_,
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const MergeTreeReaderSettings & reader_settings_,
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const Names & virt_column_names_,
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size_t part_index_in_query_,
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bool quiet)
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:
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MergeTreeBaseSelectProcessor{
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storage_.getSampleBlockForColumns(required_columns_),
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storage_, prewhere_info_, max_block_size_rows_,
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preferred_block_size_bytes_, preferred_max_column_in_block_size_bytes_,
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reader_settings_, use_uncompressed_cache_, virt_column_names_},
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required_columns{std::move(required_columns_)},
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data_part{owned_data_part_},
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all_mark_ranges(std::move(mark_ranges_)),
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part_index_in_query(part_index_in_query_),
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check_columns(check_columns_),
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path(data_part->getFullRelativePath())
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{
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/// Let's estimate total number of rows for progress bar.
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for (const auto & range : all_mark_ranges)
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total_marks_count += range.end - range.begin;
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size_t total_rows = data_part->index_granularity.getRowsCountInRanges(all_mark_ranges);
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if (!quiet)
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LOG_TRACE(log, "Reading " << all_mark_ranges.size() << " ranges from part " << data_part->name
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<< ", approx. " << total_rows
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<< (all_mark_ranges.size() > 1
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? ", up to " + toString(total_rows)
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: "")
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<< " rows starting from " << data_part->index_granularity.getMarkStartingRow(all_mark_ranges.front().begin));
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addTotalRowsApprox(total_rows);
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ordered_names = header_without_virtual_columns.getNames();
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}
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bool MergeTreeSelectProcessor::getNewTask()
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try
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{
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/// Produce no more than one task
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if (!is_first_task || total_marks_count == 0)
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{
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finish();
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return false;
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}
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is_first_task = false;
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task_columns = getReadTaskColumns(storage, data_part, required_columns, prewhere_info, check_columns);
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auto size_predictor = (preferred_block_size_bytes == 0)
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? nullptr
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: std::make_unique<MergeTreeBlockSizePredictor>(data_part, ordered_names, data_part->storage.getSampleBlock());
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/// will be used to distinguish between PREWHERE and WHERE columns when applying filter
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const auto & column_names = task_columns.columns.getNames();
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column_name_set = NameSet{column_names.begin(), column_names.end()};
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task = std::make_unique<MergeTreeReadTask>(
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data_part, all_mark_ranges, part_index_in_query, ordered_names, column_name_set, task_columns.columns,
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task_columns.pre_columns, prewhere_info && prewhere_info->remove_prewhere_column,
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task_columns.should_reorder, std::move(size_predictor));
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if (!reader)
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{
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if (use_uncompressed_cache)
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owned_uncompressed_cache = storage.global_context.getUncompressedCache();
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owned_mark_cache = storage.global_context.getMarkCache();
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reader = data_part->getReader(task_columns.columns, all_mark_ranges,
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owned_uncompressed_cache.get(), owned_mark_cache.get(), reader_settings);
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if (prewhere_info)
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pre_reader = data_part->getReader(task_columns.pre_columns, all_mark_ranges,
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owned_uncompressed_cache.get(), owned_mark_cache.get(), reader_settings);
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}
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return true;
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}
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catch (...)
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{
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/// Suspicion of the broken part. A part is added to the queue for verification.
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if (getCurrentExceptionCode() != ErrorCodes::MEMORY_LIMIT_EXCEEDED)
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storage.reportBrokenPart(data_part->name);
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throw;
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}
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void MergeTreeSelectProcessor::finish()
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{
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/** Close the files (before destroying the object).
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* When many sources are created, but simultaneously reading only a few of them,
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* buffers don't waste memory.
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*/
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reader.reset();
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pre_reader.reset();
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data_part.reset();
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}
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MergeTreeSelectProcessor::~MergeTreeSelectProcessor() = default;
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}
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