2011-08-28 02:22:23 +00:00
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#pragma once
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2018-02-19 00:45:32 +00:00
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#include <Core/Block.h>
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2019-05-17 14:34:25 +00:00
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#include <DataStreams/IBlockStream_fwd.h>
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2019-03-05 10:12:20 +00:00
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#include <Storages/TableStructureLockHolder.h>
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2010-03-04 19:20:28 +00:00
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2019-05-17 14:34:25 +00:00
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#include <boost/noncopyable.hpp>
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#include <memory>
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#include <string>
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#include <vector>
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2010-03-04 19:20:28 +00:00
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namespace DB
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{
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2016-08-17 03:29:26 +00:00
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struct Progress;
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2016-08-13 01:57:35 +00:00
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/** Interface of stream for writing data (into table, filesystem, network, terminal, etc.)
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2010-03-04 19:20:28 +00:00
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*/
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2013-01-07 00:57:43 +00:00
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class IBlockOutputStream : private boost::noncopyable
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2010-03-04 19:20:28 +00:00
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{
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public:
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2017-04-01 07:20:54 +00:00
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IBlockOutputStream() {}
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2010-03-04 19:20:28 +00:00
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2018-02-19 00:45:32 +00:00
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/** Get data structure of the stream in a form of "header" block (it is also called "sample block").
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* Header block contains column names, data types, columns of size 0. Constant columns must have corresponding values.
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* You must pass blocks of exactly this structure to the 'write' method.
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*/
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virtual Block getHeader() const = 0;
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2017-04-01 07:20:54 +00:00
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/** Write block.
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*/
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virtual void write(const Block & block) = 0;
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2010-03-04 19:20:28 +00:00
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2017-04-01 07:20:54 +00:00
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/** Write or do something before all data or after all data.
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*/
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virtual void writePrefix() {}
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virtual void writeSuffix() {}
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2014-08-14 20:27:41 +00:00
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2017-04-01 07:20:54 +00:00
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/** Flush output buffers if any.
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*/
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virtual void flush() {}
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2016-05-28 12:22:22 +00:00
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2017-04-01 07:20:54 +00:00
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/** Methods to set additional information for output in formats, that support it.
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*/
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2017-12-01 18:36:55 +00:00
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virtual void setRowsBeforeLimit(size_t /*rows_before_limit*/) {}
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virtual void setTotals(const Block & /*totals*/) {}
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virtual void setExtremes(const Block & /*extremes*/) {}
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2011-10-31 06:37:12 +00:00
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2017-04-01 07:20:54 +00:00
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/** Notify about progress. Method could be called from different threads.
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* Passed value are delta, that must be summarized.
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*/
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2017-12-01 18:36:55 +00:00
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virtual void onProgress(const Progress & /*progress*/) {}
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2016-08-17 03:29:26 +00:00
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2017-04-01 07:20:54 +00:00
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/** Content-Type to set when sending HTTP response.
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*/
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virtual std::string getContentType() const { return "text/plain; charset=UTF-8"; }
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2015-10-29 20:38:37 +00:00
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2017-04-01 07:20:54 +00:00
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virtual ~IBlockOutputStream() {}
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2014-03-19 10:45:13 +00:00
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2017-04-01 07:20:54 +00:00
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/** Don't let to alter table while instance of stream is alive.
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*/
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2019-03-07 18:04:47 +00:00
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void addTableLock(const TableStructureReadLockHolder & lock) { table_locks.push_back(lock); }
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2016-05-28 12:22:22 +00:00
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2018-02-23 10:43:24 +00:00
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private:
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2019-03-07 18:04:47 +00:00
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std::vector<TableStructureReadLockHolder> table_locks;
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2010-03-04 19:20:28 +00:00
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};
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2011-08-28 02:22:23 +00:00
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}
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