Experimental changes to vacuum to avoid loading large records entirely into memory. Currently only works in limited cases only - for rowid tables when the page-size does not change.

FossilOrigin-Name: c90e063ca9ddcdd1e9f1a2e25a3f7d6e7ee798373ad8acf65b90536b0a124c0d

1 files changed, 12 insertions, 9 deletions

diff --git a/src/insert.c b/src/insert.c
index 393cd528f..d801b4790 100644
--- a/src/insert.c
+++ b/src/insert.c
@@ -2783,11 +2783,13 @@ static int xferOptimization(
     emptySrcTest = sqlite3VdbeAddOp2(v, OP_Rewind, iSrc, 0); VdbeCoverage(v);
     if( pDest->iPKey>=0 ){
       addr1 = sqlite3VdbeAddOp2(v, OP_Rowid, iSrc, regRowid);
-      sqlite3VdbeVerifyAbortable(v, onError);
-      addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
-      VdbeCoverage(v);
-      sqlite3RowidConstraint(pParse, onError, pDest);
-      sqlite3VdbeJumpHere(v, addr2);
+      if( (db->mDbFlags & DBFLAG_Vacuum)==0 ){
+        sqlite3VdbeVerifyAbortable(v, onError);
+        addr2 = sqlite3VdbeAddOp3(v, OP_NotExists, iDest, 0, regRowid);
+        VdbeCoverage(v);
+        sqlite3RowidConstraint(pParse, onError, pDest);
+        sqlite3VdbeJumpHere(v, addr2);
+      }
       autoIncStep(pParse, regAutoinc, regRowid);
     }else if( pDest->pIndex==0 && !(db->mDbFlags & DBFLAG_VacuumInto) ){
       addr1 = sqlite3VdbeAddOp2(v, OP_NewRowid, iDest, regRowid);
@@ -2798,13 +2800,14 @@ static int xferOptimization(
     if( db->mDbFlags & DBFLAG_Vacuum ){
       sqlite3VdbeAddOp1(v, OP_SeekEnd, iDest);
       insFlags = OPFLAG_APPEND|OPFLAG_USESEEKRESULT;
+      sqlite3VdbeAddOp3(v, OP_Transfer, iDest, iSrc, regRowid);
     }else{
       insFlags = OPFLAG_NCHANGE|OPFLAG_LASTROWID|OPFLAG_APPEND;
+      sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
+      sqlite3VdbeAddOp4(v, OP_Insert, iDest, regData, regRowid,
+          (char*)pDest, P4_TABLE);
+      sqlite3VdbeChangeP5(v, insFlags);
     }
-    sqlite3VdbeAddOp3(v, OP_RowData, iSrc, regData, 1);
-    sqlite3VdbeAddOp4(v, OP_Insert, iDest, regData, regRowid,
-                      (char*)pDest, P4_TABLE);
-    sqlite3VdbeChangeP5(v, insFlags);
     sqlite3VdbeAddOp2(v, OP_Next, iSrc, addr1); VdbeCoverage(v);
     sqlite3VdbeAddOp2(v, OP_Close, iSrc, 0);
     sqlite3VdbeAddOp2(v, OP_Close, iDest, 0);