1 files changed, 56 insertions, 31 deletions

diff --git a/src/btree.c b/src/btree.c
index 342ff2bf7..8d2dc37da 100644
--- a/src/btree.c
+++ b/src/btree.c
@@ -10120,6 +10120,15 @@ end_of_check:
 ** allocation errors,  an error message held in memory obtained from
 ** malloc is returned if *pnErr is non-zero.  If *pnErr==0 then NULL is
 ** returned.  If a memory allocation error occurs, NULL is returned.
+**
+** If the first entry in aRoot[] is 0, that indicates that the list of
+** root pages is incomplete.  This is a "partial integrity-check".  This
+** happens when performing an integrity check on a single table.  The
+** zero is skipped, of course.  But in addition, the freelist checks
+** and the checks to make sure every page is referenced are also skipped,
+** since obviously it is not possible to know which pages are covered by
+** the unverified btrees.  Except, if aRoot[1] is 1, then the freelist
+** checks are still performed.
 */
 char *sqlite3BtreeIntegrityCheck(
   sqlite3 *db,  /* Database connection that is running the check */
@@ -10135,6 +10144,16 @@ char *sqlite3BtreeIntegrityCheck(
   u64 savedDbFlags = pBt->db->flags;
   char zErr[100];
   VVA_ONLY( int nRef );
+  int bPartial = 0;            /* True if not checking all btrees */
+  int bCkFreelist = 1;         /* True to scan the freelist */
+  assert( nRoot>0 );
+
+  /* aRoot[0]==0 means this is a partial check */
+  if( aRoot[0]==0 ){
+    assert( nRoot>1 );
+    bPartial = 1;
+    if( aRoot[1]!=1 ) bCkFreelist = 0;
+  }
 
   sqlite3BtreeEnter(p);
   assert( p->inTrans>TRANS_NONE && pBt->inTransaction>TRANS_NONE );
@@ -10174,29 +10193,33 @@ char *sqlite3BtreeIntegrityCheck(
 
   /* Check the integrity of the freelist
   */
-  sCheck.zPfx = "Main freelist: ";
-  checkList(&sCheck, 1, get4byte(&pBt->pPage1->aData[32]),
-            get4byte(&pBt->pPage1->aData[36]));
-  sCheck.zPfx = 0;
+  if( bCkFreelist ){
+    sCheck.zPfx = "Main freelist: ";
+    checkList(&sCheck, 1, get4byte(&pBt->pPage1->aData[32]),
+              get4byte(&pBt->pPage1->aData[36]));
+    sCheck.zPfx = 0;
+  }
 
   /* Check all the tables.
   */
 #ifndef SQLITE_OMIT_AUTOVACUUM
-  if( pBt->autoVacuum ){
-    int mx = 0;
-    int mxInHdr;
-    for(i=0; (int)i<nRoot; i++) if( mx<aRoot[i] ) mx = aRoot[i];
-    mxInHdr = get4byte(&pBt->pPage1->aData[52]);
-    if( mx!=mxInHdr ){
+  if( !bPartial ){
+    if( pBt->autoVacuum ){
+      int mx = 0;
+      int mxInHdr;
+      for(i=0; (int)i<nRoot; i++) if( mx<aRoot[i] ) mx = aRoot[i];
+      mxInHdr = get4byte(&pBt->pPage1->aData[52]);
+      if( mx!=mxInHdr ){
+        checkAppendMsg(&sCheck,
+          "max rootpage (%d) disagrees with header (%d)",
+          mx, mxInHdr
+        );
+      }
+    }else if( get4byte(&pBt->pPage1->aData[64])!=0 ){
       checkAppendMsg(&sCheck,
-        "max rootpage (%d) disagrees with header (%d)",
-        mx, mxInHdr
+        "incremental_vacuum enabled with a max rootpage of zero"
       );
     }
-  }else if( get4byte(&pBt->pPage1->aData[64])!=0 ){
-    checkAppendMsg(&sCheck,
-      "incremental_vacuum enabled with a max rootpage of zero"
-    );
   }
 #endif
   testcase( pBt->db->flags & SQLITE_CellSizeCk );
@@ -10205,7 +10228,7 @@ char *sqlite3BtreeIntegrityCheck(
     i64 notUsed;
     if( aRoot[i]==0 ) continue;
 #ifndef SQLITE_OMIT_AUTOVACUUM
-    if( pBt->autoVacuum && aRoot[i]>1 ){
+    if( pBt->autoVacuum && aRoot[i]>1 && !bPartial ){
       checkPtrmap(&sCheck, aRoot[i], PTRMAP_ROOTPAGE, 0);
     }
 #endif
@@ -10215,22 +10238,24 @@ char *sqlite3BtreeIntegrityCheck(
 
   /* Make sure every page in the file is referenced
   */
-  for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
+  if( !bPartial ){
+    for(i=1; i<=sCheck.nPage && sCheck.mxErr; i++){
 #ifdef SQLITE_OMIT_AUTOVACUUM
-    if( getPageReferenced(&sCheck, i)==0 ){
-      checkAppendMsg(&sCheck, "Page %d is never used", i);
-    }
+      if( getPageReferenced(&sCheck, i)==0 ){
+        checkAppendMsg(&sCheck, "Page %d is never used", i);
+      }
 #else
-    /* If the database supports auto-vacuum, make sure no tables contain
-    ** references to pointer-map pages.
-    */
-    if( getPageReferenced(&sCheck, i)==0 && 
-       (PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
-      checkAppendMsg(&sCheck, "Page %d is never used", i);
-    }
-    if( getPageReferenced(&sCheck, i)!=0 && 
-       (PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
-      checkAppendMsg(&sCheck, "Pointer map page %d is referenced", i);
+      /* If the database supports auto-vacuum, make sure no tables contain
+      ** references to pointer-map pages.
+      */
+      if( getPageReferenced(&sCheck, i)==0 && 
+         (PTRMAP_PAGENO(pBt, i)!=i || !pBt->autoVacuum) ){
+        checkAppendMsg(&sCheck, "Page %d is never used", i);
+      }
+      if( getPageReferenced(&sCheck, i)!=0 && 
+         (PTRMAP_PAGENO(pBt, i)==i && pBt->autoVacuum) ){
+        checkAppendMsg(&sCheck, "Pointer map page %d is referenced", i);
+      }
     }
 #endif
   }