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113 lines
3.8 KiB
C++
113 lines
3.8 KiB
C++
/* Copyright (c) 2018 BlackBerry Limited
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Licensed under the Apache License, Version 2.0 (the "License");
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you may not use this file except in compliance with the License.
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You may obtain a copy of the License at
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http://www.apache.org/licenses/LICENSE-2.0
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Unless required by applicable law or agreed to in writing, software
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distributed under the License is distributed on an "AS IS" BASIS,
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WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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See the License for the specific language governing permissions and
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limitations under the License. */
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#include <Core/Settings.h>
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#include <Common/typeid_cast.h>
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#include <Parsers/ASTWatchQuery.h>
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#include <Interpreters/InterpreterWatchQuery.h>
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#include <DataStreams/IBlockInputStream.h>
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#include <DataStreams/OneBlockInputStream.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 UNKNOWN_STORAGE;
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extern const int UNKNOWN_TABLE;
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extern const int TOO_MANY_COLUMNS;
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extern const int SUPPORT_IS_DISABLED;
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}
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BlockInputStreamPtr InterpreterWatchQuery::executeImpl()
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{
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return std::make_shared<OneBlockInputStream>(Block());
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}
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BlockIO InterpreterWatchQuery::execute()
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{
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if (!context.getSettingsRef().allow_experimental_live_view)
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throw Exception("Experimental LIVE VIEW feature is not enabled (the setting 'allow_experimental_live_view')", ErrorCodes::SUPPORT_IS_DISABLED);
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BlockIO res;
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const ASTWatchQuery & query = typeid_cast<const ASTWatchQuery &>(*query_ptr);
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String database;
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String table;
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/// Get database
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if (!query.database.empty())
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database = query.database;
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else
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database = context.getCurrentDatabase();
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/// Get table
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table = query.table;
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/// Get storage
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storage = context.tryGetTable(database, table);
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if (!storage)
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throw Exception("Table " + backQuoteIfNeed(database) + "." +
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backQuoteIfNeed(table) + " doesn't exist.",
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ErrorCodes::UNKNOWN_TABLE);
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/// List of columns to read to execute the query.
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Names required_columns = storage->getColumns().getNamesOfPhysical();
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/// Get context settings for this query
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const Settings & settings = context.getSettingsRef();
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/// Limitation on the number of columns to read.
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if (settings.max_columns_to_read && required_columns.size() > settings.max_columns_to_read)
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throw Exception("Limit for number of columns to read exceeded. "
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"Requested: " + std::to_string(required_columns.size())
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+ ", maximum: " + settings.max_columns_to_read.toString(),
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ErrorCodes::TOO_MANY_COLUMNS);
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size_t max_block_size = settings.max_block_size;
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size_t max_streams = 1;
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/// Define query info
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SelectQueryInfo query_info;
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query_info.query = query_ptr;
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/// From stage
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QueryProcessingStage::Enum from_stage = QueryProcessingStage::FetchColumns;
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QueryProcessingStage::Enum to_stage = QueryProcessingStage::Complete;
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/// Watch storage
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streams = storage->watch(required_columns, query_info, context, from_stage, max_block_size, max_streams);
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/// Constraints on the result, the quota on the result, and also callback for progress.
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if (IBlockInputStream * stream = dynamic_cast<IBlockInputStream *>(streams[0].get()))
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{
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/// Constraints apply only to the final result.
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if (to_stage == QueryProcessingStage::Complete)
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{
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IBlockInputStream::LocalLimits limits;
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limits.mode = IBlockInputStream::LIMITS_CURRENT;
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limits.size_limits.max_rows = settings.max_result_rows;
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limits.size_limits.max_bytes = settings.max_result_bytes;
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limits.size_limits.overflow_mode = settings.result_overflow_mode;
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stream->setLimits(limits);
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stream->setQuota(context.getQuota());
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}
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}
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res.in = streams[0];
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return res;
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}
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}
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