Revert to allowing a cache spill during writes of multiple pages within a

single sector as long as the spill does not require a journal sync and a
new journal header.

FossilOrigin-Name: 7d83fbae9802a56b2121d0775de54fccd743d971

manifest

@@ -1,5 +1,8 @@
-C Modify\sctime.test\sto\swork\swith\sSQLITE_THREADSAFE=2.
-D 2010-06-24T17:37:57
+-----BEGIN PGP SIGNED MESSAGE-----
+Hash: SHA1
+
+C Revert\sto\sallowing\sa\scache\sspill\sduring\swrites\sof\smultiple\spages\swithin\sa\nsingle\ssector\sas\slong\sas\sthe\sspill\sdoes\snot\srequire\sa\sjournal\ssync\sand\sa\nnew\sjournal\sheader.
+D 2010-06-24T18:36:33
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in a5cad1f8f3e021356bfcc6c77dc16f6f1952bbc3
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -156,7 +159,7 @@ F src/os_common.h a8f95b81eca8a1ab8593d23e94f8a35f35d4078f
 F src/os_os2.c 665876d5eec7585226b0a1cf5e18098de2b2da19
 F src/os_unix.c 4b03e5a8a353b51af64ba11ffec85160818b4d89
 F src/os_win.c 00385a839d54f951a73ceb98ddea29112adea05c
-F src/pager.c 24a9be67a52fb5837be4d0319904a273164dee3a
+F src/pager.c edf1f8b02b5c106bd3a3add0d06f28859195a0f8
 F src/pager.h 879fdde5a102d2f21a3135d6f647530b21c2796c
 F src/parse.y ace5c7a125d9f2a410e431ee3209034105045f7e
 F src/pcache.c 1e9aa2dbc0845b52e1b51cc39753b6d1e041cb07
@@ -825,7 +828,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
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-R 33ec6ea9feaffcac3eb447f2441d1f63
-U dan
-Z d4c71ec23bd0a529a8826dcf174b6d9d
+P c6db3b303182202a8b03512e448607bce71de914
+R f1c7e6ef66554c4040e7c5982474605c
+U drh
+Z f3f5cfd0105de6cc2c8193ae310c7e35
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manifest.uuid

@@ -1 +1 @@
-c6db3b303182202a8b03512e448607bce71de914
+7d83fbae9802a56b2121d0775de54fccd743d971

src/pager.c

@@ -305,13 +305,15 @@ struct PagerSavepoint {
 **   master journal name is only written to the journal file the first
 **   time CommitPhaseOne() is called.
 **
-** doNotSpill
+** doNotSpill, doNotSyncSpill
 **
-**   When enabled, cache spills are prohibited and the journal file cannot
-**   be synced.  This variable is set and cleared by sqlite3PagerWrite() 
-**   in order to prevent a journal sync from happening in between the
-**   journalling of two pages on the same sector.  It is also set to prevent
-**   pagerStress() from trying to use the journal during a rollback.
+**   When enabled, cache spills are prohibited.  The doNotSpill variable
+**   inhibits all cache spill and doNotSyncSpill inhibits those spills that
+**   would require a journal sync.  The doNotSyncSpill is set and cleared 
+**   by sqlite3PagerWrite() in order to prevent a journal sync from happening 
+**   in between the journalling of two pages on the same sector.  The
+**   doNotSpill value set to prevent pagerStress() from trying to use
+**   the journal during a rollback.
 **
 ** needSync
 **
@@ -356,6 +358,7 @@ struct Pager {
   u8 changeCountDone;         /* Set after incrementing the change-counter */
   u8 setMaster;               /* True if a m-j name has been written to jrnl */
   u8 doNotSpill;              /* Do not spill the cache when non-zero */
+  u8 doNotSyncSpill;          /* Do not do a spill that requires jrnl sync */
   u8 dbSizeValid;             /* Set when dbSize is correct */
   u8 subjInMemory;            /* True to use in-memory sub-journals */
   Pgno dbSize;                /* Number of pages in the database */
@@ -3518,15 +3521,19 @@ static int pagerStress(void *p, PgHdr *pPg){
   assert( pPg->pPager==pPager );
   assert( pPg->flags&PGHDR_DIRTY );
 
-  /* The doNotSpill flag is set during times when writing to the journal
-  ** is disallowed:  (1) during calls to sqlite3PagerWrite() while it
-  ** is journalling a set of two or more database pages that are stored
-  ** on the same disk sector, and (2) while performing a rollback.
+  /* The doNotSyncSpill flag is set during times when doing a sync of
+  ** journal (and adding a new header) is not allowed.  This occurs
+  ** during calls to sqlite3PagerWrite() while trying to journal multiple
+  ** pages belonging to the same sector.
   **
-  ** Similarly, if the pager has already entered the error state, do not
-  ** try to write the contents of pPg to disk.
+  ** The doNotSpill flag inhibits all cache spilling regardless of whether
+  ** or not a sync is required.  This is set during a rollback.
+  **
+  ** Spilling is also inhibited when in an error state.
   */
-  if( pPager->errCode || pPager->doNotSpill ){
+  if( pPager->errCode ) return SQLITE_OK;
+  if( pPager->doNotSpill ) return SQLITE_OK;
+  if( pPager->doNotSyncSpill && (pPg->flags & PGHDR_NEED_SYNC)!=0 ){
     return SQLITE_OK;
   }
 
@@ -4834,12 +4841,13 @@ int sqlite3PagerWrite(DbPage *pDbPage){
     int ii;                   /* Loop counter */
     int needSync = 0;         /* True if any page has PGHDR_NEED_SYNC */
 
-    /* Set the doNotSpill flag to 1. This is because we cannot allow a journal
-    ** header to be written between the pages journaled by this function.
+    /* Set the doNotSyncSpill flag 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==0 );
-    pPager->doNotSpill++;
+    assert( pPager->doNotSyncSpill==0 );
+    pPager->doNotSyncSpill++;
 
     /* This trick assumes that both the page-size and sector-size are
     ** an integer power of 2. It sets variable pg1 to the identifier
@@ -4901,8 +4909,8 @@ int sqlite3PagerWrite(DbPage *pDbPage){
       assert(pPager->needSync);
     }
 
-    assert( pPager->doNotSpill==1 );
-    pPager->doNotSpill--;
+    assert( pPager->doNotSyncSpill==1 );
+    pPager->doNotSyncSpill--;
   }else{
     rc = pager_write(pDbPage);
   }