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Overview
Comment: | Patch the sqlite3PagerWrite() method in the Pager to run a bit faster. |
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Downloads: | Tarball | ZIP archive |
Timelines: | family | ancestors | descendants | both | trunk |
Files: | files | file ages | folders |
SHA1: |
c63311e2f3344363a5ed99838fb58500 |
User & Date: | drh 2014-08-24 01:32:43.379 |
Context
2014-08-24
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02:53 | The sqlite3VdbeChangeEncoding() routine goes about 3x faster if the sqlite3VdbeMemTranslate() subroutine is not inlined. (check-in: 0c7e1b875a user: drh tags: trunk) | |
01:32 | Patch the sqlite3PagerWrite() method in the Pager to run a bit faster. (check-in: c63311e2f3 user: drh tags: trunk) | |
2014-08-23
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23:15 | Faster implementation of pcache1Fetch() (check-in: 0371cc3bb0 user: drh tags: trunk) | |
Changes
Changes to src/pager.c.
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5767 5768 5769 5770 5771 5772 5773 5774 5775 5776 5777 5778 5779 5780 5781 5782 5783 5784 5785 5786 5787 5788 | /* Update the database size and return. */ if( pPager->dbSize<pPg->pgno ){ pPager->dbSize = pPg->pgno; } return rc; } /* ** Mark a data page as writeable. This routine must be called before ** making changes to a page. The caller must check the return value ** of this function and be careful not to change any page data unless ** this routine returns SQLITE_OK. ** ** The difference between this function and pager_write() is that this ** function also deals with the special case where 2 or more pages ** fit on a single disk sector. In this case all co-resident pages ** must have been written to the journal file before returning. ** ** If an error occurs, SQLITE_NOMEM or an IO error code is returned ** as appropriate. Otherwise, SQLITE_OK. */ | > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > > | < < < < < | | | < | < < < < < < | < < < < < < < < < < < < < < < < < < < | < < < < < < < < < < < < < | < < | < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < < | 5767 5768 5769 5770 5771 5772 5773 5774 5775 5776 5777 5778 5779 5780 5781 5782 5783 5784 5785 5786 5787 5788 5789 5790 5791 5792 5793 5794 5795 5796 5797 5798 5799 5800 5801 5802 5803 5804 5805 5806 5807 5808 5809 5810 5811 5812 5813 5814 5815 5816 5817 5818 5819 5820 5821 5822 5823 5824 5825 5826 5827 5828 5829 5830 5831 5832 5833 5834 5835 5836 5837 5838 5839 5840 5841 5842 5843 5844 5845 5846 5847 5848 5849 5850 5851 5852 5853 5854 5855 5856 5857 5858 5859 5860 5861 5862 5863 5864 5865 5866 5867 5868 5869 5870 5871 5872 5873 5874 5875 5876 5877 5878 5879 5880 5881 5882 5883 5884 5885 5886 5887 5888 5889 5890 5891 5892 5893 5894 5895 5896 | /* Update the database size and return. */ if( pPager->dbSize<pPg->pgno ){ pPager->dbSize = pPg->pgno; } return rc; } /* ** This is a variant of sqlite3PagerWrite() that runs when the sector size ** is larger than the page size. SQLite makes the (reasonable) assumption that ** all bytes of a sector are written together by hardware. Hence, all bytes of ** a sector need to be journalled in case of a power loss in the middle of ** a write. ** ** Usually, the sector size is less than or equal to the page size, in which ** case pages can be individually written. This routine only runs in the exceptional ** case where the page size is smaller than the sector size. */ static SQLITE_NOINLINE int pagerWriteLargeSector(PgHdr *pPg){ int rc = SQLITE_OK; /* Return code */ Pgno nPageCount; /* Total number of pages in database file */ Pgno pg1; /* First page of the sector pPg is located on. */ int nPage = 0; /* Number of pages starting at pg1 to journal */ int ii; /* Loop counter */ int needSync = 0; /* True if any page has PGHDR_NEED_SYNC */ Pager *pPager = pPg->pPager; /* The pager that owns pPg */ Pgno nPagePerSector = (pPager->sectorSize/pPager->pageSize); /* Set the doNotSpill NOSYNC bit to 1. This is because we cannot allow ** a journal header to be written between the pages journaled by ** this function. */ assert( !MEMDB ); assert( (pPager->doNotSpill & SPILLFLAG_NOSYNC)==0 ); pPager->doNotSpill |= SPILLFLAG_NOSYNC; /* This trick assumes that both the page-size and sector-size are ** an integer power of 2. It sets variable pg1 to the identifier ** of the first page of the sector pPg is located on. */ pg1 = ((pPg->pgno-1) & ~(nPagePerSector-1)) + 1; nPageCount = pPager->dbSize; if( pPg->pgno>nPageCount ){ nPage = (pPg->pgno - pg1)+1; }else if( (pg1+nPagePerSector-1)>nPageCount ){ nPage = nPageCount+1-pg1; }else{ nPage = nPagePerSector; } assert(nPage>0); assert(pg1<=pPg->pgno); assert((pg1+nPage)>pPg->pgno); for(ii=0; ii<nPage && rc==SQLITE_OK; ii++){ Pgno pg = pg1+ii; PgHdr *pPage; if( pg==pPg->pgno || !sqlite3BitvecTest(pPager->pInJournal, pg) ){ if( pg!=PAGER_MJ_PGNO(pPager) ){ rc = sqlite3PagerGet(pPager, pg, &pPage); if( rc==SQLITE_OK ){ rc = pager_write(pPage); if( pPage->flags&PGHDR_NEED_SYNC ){ needSync = 1; } sqlite3PagerUnrefNotNull(pPage); } } }else if( (pPage = pager_lookup(pPager, pg))!=0 ){ if( pPage->flags&PGHDR_NEED_SYNC ){ needSync = 1; } sqlite3PagerUnrefNotNull(pPage); } } /* If the PGHDR_NEED_SYNC flag is set for any of the nPage pages ** starting at pg1, then it needs to be set for all of them. Because ** writing to any of these nPage pages may damage the others, the ** journal file must contain sync()ed copies of all of them ** before any of them can be written out to the database file. */ if( rc==SQLITE_OK && needSync ){ assert( !MEMDB ); for(ii=0; ii<nPage; ii++){ PgHdr *pPage = pager_lookup(pPager, pg1+ii); if( pPage ){ pPage->flags |= PGHDR_NEED_SYNC; sqlite3PagerUnrefNotNull(pPage); } } } assert( (pPager->doNotSpill & SPILLFLAG_NOSYNC)!=0 ); pPager->doNotSpill &= ~SPILLFLAG_NOSYNC; return rc; } /* ** Mark a data page as writeable. This routine must be called before ** making changes to a page. The caller must check the return value ** of this function and be careful not to change any page data unless ** this routine returns SQLITE_OK. ** ** The difference between this function and pager_write() is that this ** function also deals with the special case where 2 or more pages ** fit on a single disk sector. In this case all co-resident pages ** must have been written to the journal file before returning. ** ** If an error occurs, SQLITE_NOMEM or an IO error code is returned ** as appropriate. Otherwise, SQLITE_OK. */ int sqlite3PagerWrite(PgHdr *pPg){ assert( (pPg->flags & PGHDR_MMAP)==0 ); assert( pPg->pPager->eState>=PAGER_WRITER_LOCKED ); assert( pPg->pPager->eState!=PAGER_ERROR ); assert( assert_pager_state(pPg->pPager) ); if( pPg->pPager->sectorSize > (u32)pPg->pPager->pageSize ){ return pagerWriteLargeSector(pPg); }else{ return pager_write(pPg); } } /* ** Return TRUE if the page given in the argument was previously passed ** to sqlite3PagerWrite(). In other words, return TRUE if it is ok ** to change the content of the page. */ |
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