137 lines
4.1 KiB
C++
137 lines
4.1 KiB
C++
/*
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----
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This file is part of SECONDO.
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Copyright (C) 2019, University in Hagen, Department of Computer Science,
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Database Systems for New Applications.
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SECONDO is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 2 of the License, or
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(at your option) any later version.
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SECONDO is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with SECONDO; if not, write to the Free Software
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Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
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----
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//paragraph [10] title: [{\Large \bf ] [}]
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//paragraph [21] table1column: [\begin{quote}\begin{tabular}{l}] [\end{tabular}\end{quote}]
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//paragraph [22] table2columns: [\begin{quote}\begin{tabular}{ll}] [\end{tabular}\end{quote}]
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//paragraph [23] table3columns: [\begin{quote}\begin{tabular}{lll}] [\end{tabular}\end{quote}]
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//paragraph [24] table4columns: [\begin{quote}\begin{tabular}{llll}] [\end{tabular}\end{quote}]
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//[--------] [\hline]
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//characters [1] verbatim: [$] [$]
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//characters [2] formula: [$] [$]
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//characters [3] capital: [\textsc{] [}]
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//characters [4] teletype: [\texttt{] [}]
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//[ae] [\"a]
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//[oe] [\"o]
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//[ue] [\"u]
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//[ss] [{\ss}]
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//[<=] [\leq]
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//[#] [\neq]
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//[tilde] [\verb|~|]
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//[Contents] [\tableofcontents]
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1 Header File: ParallelQueryOptimizer
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September 2019, Fischer Thomas
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1.1 Overview
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The ~ParallelQueryOptimizer~ is part of the ~QueryProcessor~ and responsible
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to parallelize parts of the query tree. This is realized by ~par~-operators,
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which separate the operator tree in so called execution contexts. Each context
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can be executed concurrently with other contexts.
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1.2 Imports
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*/
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#ifndef PARALLEL_QUERY_OPTIMIZER_H
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#define PARALLEL_QUERY_OPTIMIZER_H
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#include "AlgebraTypes.h"
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#include <memory>
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class QueryProcessor;
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namespace parthread
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{
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/*
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1.3 ParallelQueryOptimizer
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There are two different implementations of the ~ParallelQueryOptimizer~. Which one
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is used in the ~QueryProcessor~ depends if the ~parThread~-algebra is activated.
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The algebra uses the define bellow to switch between to code segments.
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*/
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#ifdef USE_MULTIHREADED_QUERY_PROCESSING
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/*
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If the algebra is activated, the ~ParallelQueryOptimizer~ tries to read some
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settings from secondos configuration file. This is done once.
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For each new query, the ~QueryProcessor~ calls ~ParallelizeQueryPlan~ and passes
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the generated operator tree to the method. The method initializes the execution
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contexts by investigating and validating the par-operators. It is able to insert
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~par~ operators by simple rules.
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After ~ParallelQueryOptimizer~ modified the operator tree for parallel execution
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it is evaluated by the ~QueryProcessor~ in a usual way.
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*/
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class ParallelQueryOptimizer
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{
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public: //types
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static const char *ParOperatorName;
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private: //types
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struct ParallelQueryOptimizerImpl;
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public: //methods
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ParallelQueryOptimizer();
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~ParallelQueryOptimizer();
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void ParallelizeQueryPlan(QueryProcessor *queryProcessor, void *queryPlan,
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size_t memorySpent, int noMemoryOperators);
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private: //member
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std::unique_ptr<ParallelQueryOptimizerImpl> m_pImpl;
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};
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#else
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/*
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If the ~parThread~-algebra is not activated the implementation is replaced by an
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empty ~ParallelizeQueryPlan~ method. The ~QueryProcessor~ passes the ~queryPlan~,
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but it is not changed and the regular, sequential execution is used.
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*/
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class ParallelQueryOptimizer
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{
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public: //methods
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ParallelQueryOptimizer() = default;
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~ParallelQueryOptimizer() = default;
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void ParallelizeQueryPlan(QueryProcessor *queryProcessor, void *queryPlan,
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size_t memorySpent, int noMemoryOperators)
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{
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//do nothing if ParThread-library is not loaded
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};
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};
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#endif // USE_MULTIHREADED_QUERY_PROCESSING
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} // namespace parthread
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#endif // PARALLEL_QUERY_OPTIMIZER_H
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