Avoid an unnecessary malloc() for the page usage bitmap when running

a partial integrity_check.

FossilOrigin-Name: 2904fcbeebba9189cebc48e58d12fc46f78ee23d8c4d46644606691f8cabb80c

manifest

@@ -1,5 +1,5 @@
-C Fix\sa\sproblem\sallowing\sa\sCOMMIT\sfollowing\san\sOOM\sto\scause\sfts5\scorruption.
-D 2023-10-20T19:59:12.660
+C Avoid\san\sunnecessary\smalloc()\sfor\sthe\spage\susage\sbitmap\swhen\srunning\na\spartial\sintegrity_check.
+D 2023-10-21T11:06:03.224
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -659,9 +659,9 @@ F src/auth.c 19b7ccacae3dfba23fc6f1d0af68134fa216e9040e53b0681b4715445ea030b4
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
 F src/bitvec.c 9eac5f42c11914d5ef00a75605bb205e934f435c579687f985f1f8b0995c8645
 F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
-F src/btree.c 63fb3269c93924e734e0586c22816effa530cee933df4aeb2b2e045de0339280
+F src/btree.c 58f5cca2aced6888824ed69d19a0c398d288d0840b1c72c0834525e82b10c076
 F src/btree.h 03e3356f5208bcab8eed4e094240fdac4a7f9f5ddf5e91045ce589f67d47c240
-F src/btreeInt.h 91a9e0c41a0e71fa91a742ec285c63dd8dcb38b73d14fae0ed7209174ff0fdc1
+F src/btreeInt.h ef12a72b708677e48d6bc8dcd66fed25434740568b89e2cfa368093cfc5b9d15
 F src/build.c 1a9061ab67987cfa9c7f9d52ccc862a31d37ad2b05faaf0d72eeb4b4b5ee37cf
 F src/callback.c db3a45e376deff6a16c0058163fe0ae2b73a2945f3f408ca32cf74960b28d490
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
@@ -2135,8 +2135,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 5cb61c6788d7c0170b587e4667ee57d588c991a9901951762e33b97c6a135a82
-R 04eef64adc8baa80e96c39c8b85b43af
-U dan
-Z c4161b04175a3850db328dc9504c42b8
+P fba3129d1362dd3ee04d61cb3d3c48518cd98dde3febc85298f411776d60073e
+R e2705175b24cd3b2e01ea68ed578aaef
+U drh
+Z cc633995022531837a5b59b3eaccd09f
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-fba3129d1362dd3ee04d61cb3d3c48518cd98dde3febc85298f411776d60073e
+2904fcbeebba9189cebc48e58d12fc46f78ee23d8c4d46644606691f8cabb80c

src/btree.c

@@ -10459,7 +10459,7 @@ static void checkAppendMsg(
 ** corresponds to page iPg is already set.
 */
 static int getPageReferenced(IntegrityCk *pCheck, Pgno iPg){
-  assert( iPg<=pCheck->nPage && sizeof(pCheck->aPgRef[0])==1 );
+  assert( iPg<=pCheck->nCkPage && sizeof(pCheck->aPgRef[0])==1 );
   return (pCheck->aPgRef[iPg/8] & (1 << (iPg & 0x07)));
 }
 
@@ -10467,7 +10467,7 @@ static int getPageReferenced(IntegrityCk *pCheck, Pgno iPg){
 ** Set the bit in the IntegrityCk.aPgRef[] array that corresponds to page iPg.
 */
 static void setPageReferenced(IntegrityCk *pCheck, Pgno iPg){
-  assert( iPg<=pCheck->nPage && sizeof(pCheck->aPgRef[0])==1 );
+  assert( iPg<=pCheck->nCkPage && sizeof(pCheck->aPgRef[0])==1 );
   pCheck->aPgRef[iPg/8] |= (1 << (iPg & 0x07));
 }
 
@@ -10481,7 +10481,8 @@ static void setPageReferenced(IntegrityCk *pCheck, Pgno iPg){
 ** Also check that the page number is in bounds.
 */
 static int checkRef(IntegrityCk *pCheck, Pgno iPage){
-  if( iPage>pCheck->nPage || iPage==0 ){
+  if( iPage>pCheck->nCkPage || iPage==0 ){
+    if( pCheck->nCkPage==0 ) return 0;  /* omit reference counting */
     checkAppendMsg(pCheck, "invalid page number %u", iPage);
     return 1;
   }
@@ -10979,19 +10980,24 @@ int sqlite3BtreeIntegrityCheck(
   sCheck.db = db;
   sCheck.pBt = pBt;
   sCheck.pPager = pBt->pPager;
-  sCheck.nPage = btreePagecount(sCheck.pBt);
+  sCheck.nCkPage = btreePagecount(sCheck.pBt);
   sCheck.mxErr = mxErr;
   sqlite3StrAccumInit(&sCheck.errMsg, 0, zErr, sizeof(zErr), SQLITE_MAX_LENGTH);
   sCheck.errMsg.printfFlags = SQLITE_PRINTF_INTERNAL;
-  if( sCheck.nPage==0 ){
+  if( sCheck.nCkPage==0 ){
     goto integrity_ck_cleanup;
   }
 
-  sCheck.aPgRef = sqlite3MallocZero((sCheck.nPage / 8)+ 1);
+  if( bPartial ){
+    sCheck.nCkPage = 0;
+    sCheck.aPgRef = 0;
+  }else{
+    sCheck.aPgRef = sqlite3MallocZero((sCheck.nCkPage / 8)+ 1);
     if( !sCheck.aPgRef ){
       checkOom(&sCheck);
       goto integrity_ck_cleanup;
     }
+  }
   sCheck.heap = (u32*)sqlite3PageMalloc( pBt->pageSize );
   if( sCheck.heap==0 ){
     checkOom(&sCheck);
@@ -10999,7 +11005,7 @@ int sqlite3BtreeIntegrityCheck(
   }
 
   i = PENDING_BYTE_PAGE(pBt);
-  if( i<=sCheck.nPage ) setPageReferenced(&sCheck, i);
+  if( i<=sCheck.nCkPage ) setPageReferenced(&sCheck, i);
 
   /* Check the integrity of the freelist
   */
@@ -11050,7 +11056,7 @@ int sqlite3BtreeIntegrityCheck(
   /* Make sure every page in the file is referenced
   */
   if( !bPartial ){
-    for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
+    for(i=1; i<=sCheck.nCkPage && sCheck.mxErr; i++){
 #ifdef SQLITE_OMIT_AUTOVACUUM
       if( getPageReferenced(&sCheck, i)==0 ){
         checkAppendMsg(&sCheck, "Page %u: never used", i);

src/btreeInt.h

@@ -695,7 +695,7 @@ struct IntegrityCk {
   BtShared *pBt;    /* The tree being checked out */
   Pager *pPager;    /* The associated pager.  Also accessible by pBt->pPager */
   u8 *aPgRef;       /* 1 bit per page in the db (see above) */
-  Pgno nPage;       /* Number of pages in the database */
+  Pgno nCkPage;     /* Pages in the database.  0 for partial check */
   int mxErr;        /* Stop accumulating errors when this reaches zero */
   int nErr;         /* Number of messages written to zErrMsg so far */
   int rc;           /* SQLITE_OK, SQLITE_NOMEM, or SQLITE_INTERRUPT */