Patch the sqlite3PagerWrite() method in the Pager to run a bit faster.

FossilOrigin-Name: c63311e2f3344363a5ed99838fb5850004eaee30

manifest

@@ -1,5 +1,5 @@
-C Faster\simplementation\sof\spcache1Fetch()
+C Patch\sthe\ssqlite3PagerWrite()\smethod\sin\sthe\sPager\sto\srun\sa\sbit\sfaster.
-D 2014-08-23T23:15:31.233
+D 2014-08-24T01:32:43.379
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in 5eb79e334a5de69c87740edd56af6527dd219308
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -211,7 +211,7 @@ F src/os_setup.h c9d4553b5aaa6f73391448b265b89bed0b890faa
 F src/os_unix.c bd7df3094a60915c148517504c76df4fca24e542
 F src/os_win.c d067fce558a5032e6e6afe62899e5397bf63cf3e
 F src/os_win.h 09e751b20bbc107ffbd46e13555dc73576d88e21
-F src/pager.c f6bb1fa6cdf2062f2d8aec3e64db302bca519ab8
+F src/pager.c c831b0df879114915c08dc5a0188f9f22c48403b
 F src/pager.h ffd5607f7b3e4590b415b007a4382f693334d428
 F src/parse.y 22d6a074e5f5a7258947a1dc55a9bf946b765dd0
 F src/pcache.c da602c5447051705cab41604bf3276815eb569d0
@@ -1188,7 +1188,7 @@ F tool/vdbe_profile.tcl 67746953071a9f8f2f668b73fe899074e2c6d8c1
 F tool/warnings-clang.sh f6aa929dc20ef1f856af04a730772f59283631d4
 F tool/warnings.sh 0abfd78ceb09b7f7c27c688c8e3fe93268a13b32
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
-P bd41d394d48516eb7d8ddc46abdcb427aa80173e
+P 0371cc3bb07448bcd64fd671f3e71bb7f30deb4d
-R d2491d65f44f8709d1d156c840c25703
+R 2fe545d9c9446b3adf94c91625adc119
 U drh
-Z 15bb2365f5f8da3e5de34ee820ad0674
+Z 79e99766e8b4bdebd57118e507ef67dc

manifest.uuid

@@ -1 +1 @@
-0371cc3bb07448bcd64fd671f3e71bb7f30deb4d
+c63311e2f3344363a5ed99838fb5850004eaee30

src/pager.c

@@ -5772,6 +5772,97 @@ static int pager_write(PgHdr *pPg){
   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 
@@ -5786,96 +5877,16 @@ static int pager_write(PgHdr *pPg){
 ** If an error occurs, SQLITE_NOMEM or an IO error code is returned
 ** as appropriate. Otherwise, SQLITE_OK.
 */
-int sqlite3PagerWrite(DbPage *pDbPage){
+int sqlite3PagerWrite(PgHdr *pPg){
-  int rc = SQLITE_OK;
-
-  PgHdr *pPg = pDbPage;
-  Pager *pPager = pPg->pPager;
-
   assert( (pPg->flags & PGHDR_MMAP)==0 );
-  assert( pPager->eState>=PAGER_WRITER_LOCKED );
+  assert( pPg->pPager->eState>=PAGER_WRITER_LOCKED );
-  assert( pPager->eState!=PAGER_ERROR );
+  assert( pPg->pPager->eState!=PAGER_ERROR );
-  assert( assert_pager_state(pPager) );
+  assert( assert_pager_state(pPg->pPager) );
-
+  if( pPg->pPager->sectorSize > (u32)pPg->pPager->pageSize ){
-  if( pPager->sectorSize > (u32)pPager->pageSize ){
+    return pagerWriteLargeSector(pPg);
-    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 */
-    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;
   }else{
-    rc = pager_write(pDbPage);
+    return pager_write(pPg);
   }
-  return rc;
 }
 
 /*