-C Fix\sa\sdatabase\scorruption\sproblem\sthat\scan\soccur\sin\sauto-vacuum\smode\swhen\na\smalloc()\sfailure\scauses\sa\sstatement\srollback,\sadditional\sstatements\nare\srun\sin\sthe\ssame\stransaction,\sthen\sthe\stotal\stransaction\srolls\sback.\s(CVS\s4079)
-D 2007-06-16T04:42:12
+C A\sminor\slogic\scorrection\sin\sthe\sprevious\scheck-in.\s\sAlso\sadded\sa\slengthy\r\ncomment\sdescribing\sthe\smeanings\sof\svarious\sflags\sin\sthe\s\r\n{quote:\sPgHdr}\sstructure.\s(CVS\s4080)
+D 2007-06-16T11:17:46
F Makefile.in b9971ab07868cf2b3209fe3bf8c52e7e25af4193
F Makefile.linux-gcc 2d8574d1ba75f129aba2019f0b959db380a90935
F README 9c4e2d6706bdcc3efdd773ce752a8cdab4f90028
F src/os_unix.h 5768d56d28240d3fe4537fac08cc85e4fb52279e
F src/os_win.c d868d5f9e95ec9c1b9e2a30c54c996053db6dddd
F src/os_win.h 41a946bea10f61c158ce8645e7646b29d44f122b
-F src/pager.c a8e5c2fd00737ddd7d8c8416d0fdbbf904d78b64
+F src/pager.c d7e2b57f573aa3e4183c6112a4e7b5dd480b25e1
F src/pager.h 94110a5570dca30d54a883e880a3633b2e4c05ae
F src/parse.y 2ed1d91fdcb4ae7ae7d1f4674544297807c7cc26
F src/pragma.c 0d25dad58bdfd6789943a10f1b9663c2eb85b96d
F www/vdbe.tcl 87a31ace769f20d3627a64fa1fade7fed47b90d0
F www/version3.tcl 890248cf7b70e60c383b0e84d77d5132b3ead42b
F www/whentouse.tcl fc46eae081251c3c181bd79c5faef8195d7991a5
-P dcdb20f81ae923f6f56d75c7b8b89a0b3abff954
-R e52cc159103410bf628cb2caa9ba87b2
+P c9dcf2b926c99ff9cee68589f364461ab2a1d11f
+R 74c0238a5e30e1bd72611d04385a904b
U drh
-Z 5e8ccb501c2183f5e479995480e6033d
+Z 50e1ec7f55bb4b42bf19c7a688ba2066
** file simultaneously, or one process from reading the database while
** another is writing.
**
-** @(#) $Id: pager.c,v 1.345 2007/06/16 04:42:12 drh Exp $
+** @(#) $Id: pager.c,v 1.346 2007/06/16 11:17:46 drh Exp $
*/
#ifndef SQLITE_OMIT_DISKIO
#include "sqliteInt.h"
** The PgHdr.dirty flag is set when sqlite3PagerWrite() is called and
** is cleared again when the page content is written back to the original
** database file.
+**
+** Details of important structure elements:
+**
+** needSync
+**
+** If this is true, this means that it is not safe to write the page
+** content to the database because the original content needed
+** for rollback has not by synced to the main rollback journal.
+** The original content may have been written to the rollback journal
+** but it has not yet been synced. So we cannot write to the database
+** file because power failure might cause the page in the journal file
+** to never reach the disk. It is as if the write to the journal file
+** does not occur until the journal file is synced.
+**
+** This flag is false if the page content exactly matches what
+** currently exists in the database file. The needSync flag is also
+** false if the original content has been written to the main rollback
+** journal and synced. If the page represents a new page that has
+** been added onto the end of the database during the current
+** transaction, the needSync flag is true until the original database
+** size in the journal header has been synced to disk.
+**
+** inJournal
+**
+** This is true if the original page has been written into the main
+** rollback journal. This is always false for new pages added to
+** the end of the database file during the current transaction.
+** And this flag says nothing about whether or not the journal
+** has been synced to disk. For pages that are in the original
+** database file, the following expression should always be true:
+**
+** inJournal = (pPager->aInJournal[(pgno-1)/8] & (1<<((pgno-1)%8))!=0
+**
+** The pPager->aInJournal[] array is only valid for the original
+** pages of the database, not new pages that are added to the end
+** of the database, so obviously the above expression cannot be
+** valid for new pages. For new pages inJournal is always 0.
+**
+** dirty
+**
+** When true, this means that the content of the page has been
+** modified and needs to be written back to the database file.
+** If false, it means that either the content of the page is
+** unchanged or else the content is unimportant and we do not
+** care whether or not it is preserved.
+**
+** alwaysRollback
+**
+** This means that the sqlite3PagerDontRollback() API should be
+** ignored for this page. The DontRollback() API attempts to say
+** that the content of the page on disk is unimportant (it is an
+** unused page on the freelist) so that it is unnecessary to
+** rollback changes to this page because the content of the page
+** can change without changing the meaning of the database. This
+** flag overrides any DontRollback() attempt. This flag is set
+** when a page that originally contained valid data is added to
+** the freelist. Later in the same transaction, this page might
+** be pulled from the freelist and reused for something different
+** and at that point the DontRollback() API will be called because
+** pages taken from the freelist do not need to be protected by
+** the rollback journal. But this flag says that the page was
+** not originally part of the freelist so that it still needs to
+** be rolled back in spite of any subsequent DontRollback() calls.
+**
+** needRead
+**
+** This flag means (when true) that the content of the page has
+** not yet been loaded from disk. The in-memory content is just
+** garbage. (Actually, we zero the content, but you should not
+** make any assumptions about the content nevertheless.) If the
+** content is needed in the future, it should be read from the
+** original database file.
*/
typedef struct PgHdr PgHdr;
struct PgHdr {
}
if( pPager->aInJournal && (int)pgno<=pPager->origDbSize ){
pPg->inJournal = (pPager->aInJournal[pgno/8] & (1<<(pgno&7)))!=0;
- }else if( (int)pgno>=pPager->origDbSize ){
- pPg->inJournal = 1;
}else{
pPg->inJournal = 0;
- assert( pPg->needSync==0 );
+ assert( pPg->needSync==0 || (int)pgno>pPager->origDbSize );
}
/* Change the page number for pPg and insert it into the new hash-chain. */
projects / thirdparty / sqlite.git / commitdiff
