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

a partial integrity_check.

FossilOrigin-Name: 2904fcbeebba9189cebc48e58d12fc46f78ee23d8c4d46644606691f8cabb80c

2 files changed, 18 insertions, 12 deletions

diff --git a/src/btree.c b/src/btree.c
index 3c4f00d15..ec4d02d19 100644
--- a/src/btree.c
+++ b/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;
   }
@@ -10979,18 +10980,23 @@ 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( !sCheck.aPgRef ){
-    checkOom(&sCheck);
-    goto integrity_ck_cleanup;
+  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 ){
@@ -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);
diff --git a/src/btreeInt.h b/src/btreeInt.h
index 26a0bc686..563e15f8a 100644
--- a/src/btreeInt.h
+++ b/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 */