0154f7d29d
This commit should significantly improve sequential write thoughput. I found a segfault bug this morning, but cannot reproduce. Could be a heisenbug, or could have been a hardware fault (gojira repeatedly kernel paniced, then both problems went away...)
181 lines
6.6 KiB
C
181 lines
6.6 KiB
C
/*---
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This software is copyrighted by the Regents of the University of
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California, and other parties. The following terms apply to all files
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associated with the software unless explicitly disclaimed in
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individual files.
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The authors hereby grant permission to use, copy, modify, distribute,
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and license this software and its documentation for any purpose,
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provided that existing copyright notices are retained in all copies
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and that this notice is included verbatim in any distributions. No
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written agreement, license, or royalty fee is required for any of the
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authorized uses. Modifications to this software may be copyrighted by
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their authors and need not follow the licensing terms described here,
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provided that the new terms are clearly indicated on the first page of
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each file where they apply.
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IN NO EVENT SHALL THE AUTHORS OR DISTRIBUTORS BE LIABLE TO ANY PARTY
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FOR DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL DAMAGES
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ARISING OUT OF THE USE OF THIS SOFTWARE, ITS DOCUMENTATION, OR ANY
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DERIVATIVES THEREOF, EVEN IF THE AUTHORS HAVE BEEN ADVISED OF THE
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POSSIBILITY OF SUCH DAMAGE.
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THE AUTHORS AND DISTRIBUTORS SPECIFICALLY DISCLAIM ANY WARRANTIES,
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INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE, AND
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NON-INFRINGEMENT. THIS SOFTWARE IS PROVIDED ON AN "AS IS" BASIS, AND
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THE AUTHORS AND DISTRIBUTORS HAVE NO OBLIGATION TO PROVIDE
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MAINTENANCE, SUPPORT, UPDATES, ENHANCEMENTS, OR MODIFICATIONS.
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GOVERNMENT USE: If you are acquiring this software on behalf of the
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U.S. government, the Government shall have only "Restricted Rights" in
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the software and related documentation as defined in the Federal
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Acquisition Regulations (FARs) in Clause 52.227.19 (c) (2). If you are
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acquiring the software on behalf of the Department of Defense, the
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software shall be classified as "Commercial Computer Software" and the
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Government shall have only "Restricted Rights" as defined in Clause
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252.227-7013 (c) (1) of DFARs. Notwithstanding the foregoing, the
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authors grant the U.S. Government and others acting in its behalf
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permission to use and distribute the software in accordance with the
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terms specified in this license.
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---*/
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/**
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* @file
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* Manages the page buffer
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bufferManager - Provides cached page handling, delegates to blob
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manager when necessary. Doesn't implement an eviction policy.
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That is left to a cacheManager. (Multiple cacheManagers could be
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used with a single bufferManager.)
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@todo Allow error checking!
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@todo Refactoring for lock manager
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Possible interface for lockManager:
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Define three classes of objects that the lock manager is interested in:
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Transactions,
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Operations,
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Predicates.
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Stasis already has operations and transactions, and these can be
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relatively unchanged. Predicates are read only operations that
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return a set of tuples. Tread() is the simplest predicate.
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Index scans provide a motivating example.
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See http://research.microsoft.com/%7Eadya/pubs/icde00.pdf
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(Generalized Isolation Level Definitions, Adya, Liskov, O'Neil,
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2000) for a theoretical discussion of general locking schemes..
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Locking functions can return errors such as DEADLOCK, etc.
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When such a value is returned, the transaction aborts, and an
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error is passed up to the application.
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@ingroup BUFFER_MANAGER
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* $Id$
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*/
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#ifndef __BUFFERMANAGER_H__
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#define __BUFFERMANAGER_H__
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BEGIN_C_DECLS
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#include <stasis/pageHandle.h>
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/**
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* Obtain a pointer to a page from the buffer manager. The page will
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* be pinned, and the pointer valid until releasePage is called.
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*
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* @param xid The transaction that is pinning the page (used by page-level locking implementations.)
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*
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* @param pageid ID of the page you want to load
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*
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* @return fully formed Page type
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*/
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Page * loadPage(int xid, pageid_t pageid);
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Page * loadPageOfType(int xid, pageid_t pageid, pagetype_t type);
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Page * loadUninitializedPage(int xid, pageid_t pageid);
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Page * loadPageForOperation(int xid, pageid_t pageid, int op);
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Page * getCachedPage(int xid, const pageid_t pageid);
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/**
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This is the function pointer that stasis_buffer_manager_open sets in order to
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override loadPage.
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*/
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extern Page * (*loadPageImpl)(int xid, pageid_t pageid, pagetype_t type);
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extern Page * (*loadUninitPageImpl)(int xid, pageid_t pageid);
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/**
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Get a page from cache. This function should never block on I/O.
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@return a pointer to the page, or NULL if the page is not in cache, or is being read from disk.
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*/
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extern Page * (*getCachedPageImpl)(int xid, const pageid_t pageid);
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/**
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loadPage aquires a lock when it is called, effectively pinning it
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in memory. releasePage releases this lock.
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*/
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void releasePage(Page *p);
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/**
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This is the function pointer that stasis_buffer_manager_open sets in order to
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override releasePage.
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*/
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extern void (*releasePageImpl)(Page * p);
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/**
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* initialize buffer manager
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* @return 0 on success
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* @return error code on failure
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*/
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/**
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This is used by truncation to move dirty pages from Stasis cache
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into the operating system cache. Once writeBackPage(p) returns,
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calling forcePages() will synchronously force page number p to
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disk.
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(Not all buffer managers support synchronous writes to stable
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storage. For compatibility, such buffer managers should ignore
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this call.)
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@return 0 on success, ENOENT if the page is not in cache, and EBUSY if the page is pinned.
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*/
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extern int (*writeBackPage)(pageid_t p);
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/**
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Force any written back pages to disk.
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@see writeBackPage for more information.
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If the buffer manager doesn't support stable storage, this call is
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a no-op.
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*/
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extern void (*forcePages)();
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/**
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Force written back pages that fall within a particular range to disk.
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This does not force page that have not been written to with pageWrite().
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@param start the first pageid to be forced to disk
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@param stop the page after the last page to be forced to disk.
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*/
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extern void (*forcePageRange)(pageid_t start, pageid_t stop);
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extern void (*stasis_buffer_manager_simulate_crash)();
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int stasis_buffer_manager_open(int type, stasis_page_handle_t * ph);
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/**
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* will write out any dirty pages, assumes that there are no running
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* transactions
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*/
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extern void (*stasis_buffer_manager_close)();
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#ifdef PROFILE_LATCHES_WRITE_ONLY
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#define loadPage(x,y) __profile_loadPage((x), (y), __FILE__, __LINE__)
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#define releasePage(x) __profile_releasePage((x))
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compensated_function void __profile_releasePage(Page * p);
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compensated_function Page * __profile_loadPage(int xid, pageid_t pageid, char * file, int line);
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#endif
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END_C_DECLS
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#endif
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