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264cff6415
TODO (suggested by Nikolai) 1. Build query plan fro current query (inside storage::read) up to WithMergableState 2. Check, that plan is simple enough: Aggregating - Expression - Filter - ReadFromStorage (or simplier) 3. Check, that filter is the same as filter in projection, and also expression calculates the same aggregation keys as in projection 4. Return WithMergableState if projection applies 3 will be easier to do with ActionsDAG, cause it sees all functions, and dependencies are direct (but it is possible with ExpressionActions also) Also need to figure out how prewhere works for projections, and row_filter_policies. wip
76 lines
2.4 KiB
C++
76 lines
2.4 KiB
C++
#include <Storages/MergeTree/ProjectionKeyActions.h>
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#include <Core/Block.h>
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#include <Parsers/ASTFunction.h>
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#include <Parsers/ASTIdentifier.h>
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#include <Parsers/ASTLiteral.h>
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#include <AggregateFunctions/AggregateFunctionFactory.h>
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namespace DB
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{
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namespace
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{
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bool isKeyPossiblyWrappedByFunctionsImpl(
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ASTPtr & node, const Block & key_block, String & out_key_column_name, DataTypePtr & out_key_column_type)
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{
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String name = node->getColumnNameWithoutAlias();
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const auto * it = key_block.findByName(name);
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if (it)
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{
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out_key_column_name = it->name;
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out_key_column_type = it->type;
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node = std::make_shared<ASTIdentifier>(it->name);
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return true;
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}
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if (const auto * func = node->as<ASTFunction>())
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{
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// Projection aggregating keys cannot be inside another aggregate function. It's possible but doesn't make sense.
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if (AggregateFunctionFactory::instance().isAggregateFunctionName(func->name))
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return false;
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auto & args = func->arguments->children;
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for (auto & arg : args)
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{
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if (!isKeyPossiblyWrappedByFunctionsImpl(arg, key_block, out_key_column_name, out_key_column_type))
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return false;
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}
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return true;
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}
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else if (node->as<ASTLiteral>())
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return true;
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return false;
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}
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bool isKeyPossiblyWrappedByFunctions(
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ASTPtr & node, const Block & key_block, String & out_key_res_column_name, DataTypePtr & out_key_res_column_type)
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{
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String key_column_name;
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DataTypePtr key_column_type;
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if (!isKeyPossiblyWrappedByFunctionsImpl(node, key_block, key_column_name, key_column_type))
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return false;
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out_key_res_column_name = key_column_name;
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out_key_res_column_type = key_column_type;
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return true;
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}
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}
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bool ProjectionKeyActions::add(ASTPtr & node, const std::string & node_name, Block & key_block)
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{
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String out_key_res_column_name;
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DataTypePtr out_key_res_column_type;
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if (isKeyPossiblyWrappedByFunctions(node, key_block, out_key_res_column_name, out_key_res_column_type))
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{
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key_block.erase(out_key_res_column_name);
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func_map[{out_key_res_column_name, out_key_res_column_type}] = node;
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name_map[node_name] = out_key_res_column_name;
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return true;
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}
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return false;
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}
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}
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