/* Copyright (C) 2014 InfiniDB, Inc. This program is free software; you can redistribute it and/or modify it under the terms of the GNU General Public License as published by the Free Software Foundation; version 2 of the License. This program is distributed in the hope that it will be useful, but WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details. You should have received a copy of the GNU General Public License along with this program; if not, write to the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */ /****************************************************************************** * $Id: objectidmanager.h 9744 2013-08-07 03:32:19Z bwilkinson $ * *****************************************************************************/ /** @file * class ObjectIDManager interface. */ #pragma once #include #include #include "dbrm.h" namespace execplan { /** @brief The class that manages the Object ID space * * The class that manages the allocation and deallocation of IDs * for objects in the database. */ class ObjectIDManager { public: /** @brief Default constructor * * @note Throws ios::failure on a file IO error */ ObjectIDManager(); virtual ~ObjectIDManager(); /** @brief Allocate one Object ID * * @return The allocated OID (>= 0) on success, -1 on error. */ int allocOID(); /** @brief Allocate a contiguous range of Object IDs * * @param num The number of contiguous Object IDs to allocate * @return The first OID allocated on success, -1 on failure */ int allocOIDs(int num); /** @brief Allocates a new oid for a version buffer file, associates it * with dbroot. * * @return Returns -1 on all errors. */ int allocVBOID(uint32_t dbroot); /** @brief Returns the DBRoot of the given version buffer OID, or -1 on error. */ int getDBRootOfVBOID(uint32_t vboid); /** @brief Returns the VB OID -> DB Root mapping. ret[0] = dbroot of VB OID 0 * * @return vector where index n = dbroot of VBOID n. * @throw runtime_exception on error */ std::vector getVBOIDToDBRootMap(); /** @brief Return an OID to the pool * * @param oid The OID to return */ void returnOID(int oid); /** @brief Return a list of OIDs to the pool * * @param start The first OID to return * @param end The last OID to return */ void returnOIDs(int start, int end); /** @brief Counts the number of allocated OIDs * * @note This currently assumes the bitmap length is a multiple of 4096 * @return The number of allocated OIDs */ int size(); /** @brief Get the OID bitmap filename */ const std::string getFilename() const; private: std::string fFilename; BRM::DBRM dbrm; #if 0 static const int FreeListEntries = 256; static const int HeaderSize = FreeListEntries * sizeof(FEntry); static const int FileSize = HeaderSize + 2097152; // (2^24/8) static const int MaxRetries = 10; /// max number of retries on file operations int fFd; /// file descriptor referencing the bitmap file /** @brief Grab the file lock * * Grab the file lock. * @note Throws ios::failure after MaxRetries hard errors */ void lockFile() const; /** @brief Reliably reads data from the bitmap file * * Reliably reads data from the bitmap file. * @note Throws ios::failure after MaxRetries hard errors * @note Caller is responsible for locking & unlocking * @param buf the buffer to read into * @param offset the offset to start reading at * @param size the number of bytes to read into buf */ void readData(uint8_t* buf, off64_t offset, int size) const; /** @brief Reliably writes data to the bitmap file * * Reliably write data to the bitmap file. * @note Throws ios::failure after MaxRetries hard errors * @note Caller is responsible for locking & unlocking * @param buf the data to write * @param offset the offset to start writing at * @param size the number of bytes to write */ void writeData(uint8_t* buf, off64_t offset, int size) const; /** @brief If there is no bitmap file yet, this is used to make one * * If there is no bitmap file yet, this is used to make one. * @note It assumes no OIDs are allocated, we may want * to fully rebuild it from actual DB contents instead. */ void initializeBitmap() const; /** @brief Allocates OIDs using a designated freelist entry * * Allocates OIDs using a designated freelist entry * @param fe The freelist entry to use. * @param num The number of OIDs to allocate from that block */ void useFreeListEntry(struct FEntry& fe, int num); /** @brief This allocates or deallocates a block of OIDs * * This allocates or deallocates a block of OIDs * @param start The first OID to alloc/dealloc * @param end The number of OIDs to flip * @param mode mode = 0 means 'allocate', mode = 1 means 'deallocate' */ void flipOIDBlock(int start, int num, int mode) const; /** @brief This scans the whole bitmap for a block of free OIDs * * This scans the whole bitmap for a block of free OIDs * @param num the size of the block to locate * @param freelist the freelist * @return The first OID of the block allocated, or -1 if there is no match */ int fullScan(int num, struct FEntry* freelist) const; /** @brief This is used by allocOIDs to fix the freelist after a full scan * * This is used by fullScan to fix the freelist before an allocation * @param freelist The freelist * @param start The first OID of the block allocated by fullScan * @param num The number of OIDs allocated * @note At the moment it throws logic_error if it detects a specific error in * fullscan */ void patchFreelist(struct FEntry* freelist, int start, int num) const; #endif }; } // namespace execplan