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1780.3.1
by David Shrewsbury
Add code to manage multi-GPB-message transactions and output them atomically. |
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/* -*- mode: c++; c-basic-offset: 2; indent-tabs-mode: nil; -*-
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* vim:expandtab:shiftwidth=2:tabstop=2:smarttab:
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*
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* Copyright (c) 2010 David Shrewsbury <shrewsbury.dave@gmail.com>
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*
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* This program 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; version 2 of the License.
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*
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* This program 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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*
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* You should have received a copy of the GNU General Public License
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* along with this program; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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/**
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* @file
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* Declaration of a class used to manage Transaction messages so that they
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* can be retrieved as a collection.
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*/
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#ifndef DRIZZLED_MESSAGE_TRANSACTION_MANAGER_H
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#define DRIZZLED_MESSAGE_TRANSACTION_MANAGER_H
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#include "drizzled/message/transaction.pb.h" |
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#include <string> |
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#include <vector> |
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1780.3.3
by David Shrewsbury
Replace std::map with boost::unordered_map |
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#include <boost/unordered_map.hpp> |
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1780.3.1
by David Shrewsbury
Add code to manage multi-GPB-message transactions and output them atomically. |
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typedef std::vector<std::string> MsgBufferType; |
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namespace drizzled |
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{
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namespace message |
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{
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/**
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* Simple (example) Transaction message buffer and content manager.
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*
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* @details
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* This class groups Transaction messages together by transaction ID and
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* buffers them together in memory. Obviously, this could eat up a lot of
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* memory if you have very large transactions. A more robust implementation
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* would buffer larger transactions to disk rather than memory.
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*
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* @note
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* Once you have a complete transaction and have processed it, you should
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* call remove() to remove the cache contents for that transaction from memory.
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*/
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class TransactionManager |
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{
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public: |
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/**
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* Store the given Transaction message in a buffer.
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*
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* @param[in] transaction Pointer to the Transaction message to store.
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*
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* @retval true Success
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* @retval false Failure
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*/
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bool store(const drizzled::message::Transaction &transaction); |
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/**
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* Clear the buffer contents for a given transaction ID.
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*
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* @param[in] trx_id The transaction ID for the transaction to remove
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*
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* @retval true Success
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* @retval false Failure
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*/
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bool remove(uint64_t trx_id); |
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/**
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* Check to see if any Transaction messages exist for a given transaction.
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*
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* @param[in] trx_id The transaction ID to check for.
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*
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* @retval true Transaction messages exist
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* @retval false No Transaction messages found
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*/
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bool contains(uint64_t trx_id); |
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/**
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* Return number of cached elements for the given transaction ID.
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*
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* @param[in] trx_id Transaction ID
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*
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* @returns The number of cached elements associated with trx_id.
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*/
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uint32_t getTransactionBufferSize(uint64_t trx_id); |
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/**
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* Retrieve a Transaction message from the managed cache.
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*
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* Caller must supply a Transaction message to populate. The Transaction
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* message to retrieve is indexed by a combination of transaction ID and
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* position.
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*
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* @param[out] transaction Transaction message to populate
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* @param[in] trx_id Transaction ID
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* @param[in] position Index into the buffer associated with trx_id
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*
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* @retval true Success
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* @retval false Failure
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*/
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bool getTransactionMessage(drizzled::message::Transaction &transaction, |
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uint64_t trx_id, |
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uint32_t position); |
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private: |
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/**
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* Our message buffer cache, mapped by the transaction ID.
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*
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* We organize Transactions messages by grouping them by transaction ID,
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* then storing the messages in std::vectors in std::string format. The
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* string format is convenient because it can be easily copied around
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* (GPB messages do not provide deep copying).
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*/
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1780.3.3
by David Shrewsbury
Replace std::map with boost::unordered_map |
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boost::unordered_map<uint64_t,MsgBufferType> cache; |
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1780.3.1
by David Shrewsbury
Add code to manage multi-GPB-message transactions and output them atomically. |
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};
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} /* namespace message */ |
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} /* namespace drizzled */ |
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#endif /* DRIZZLED_MESSAGE_TRANSACTION_MANAGER_H */ |