diff --git a/manifest b/manifest
index d6dc655417..c7638368d1 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Further\ssize\sand\sperformance\soptimizations\sfor\ssqlite3VdbeMemSetStr().
-D 2022-03-28T18:34:40.795
+C Fix\sthe\ssqlite3_result_xxxxx()\sroutines\sso\sthat\sthey\sall\scheck\sfor\sand\nperform\sany\snecessary\stext\sencoding\sconversions\sand\scheck\sfor\soversize\nstrings\sand\sBLOBs.\s\sThus\sthose\schecks\scan\sbe\sdone\swhere\sthey\sare\smost\nefficient\sand\savoided\sin\scases\slike\sOP_Function\swhere\sthey\sare\smore\nexpensive.
+D 2022-03-29T01:43:09.917
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -624,13 +624,13 @@ F src/upsert.c 8789047a8f0a601ea42fa0256d1ba3190c13746b6ba940fe2d25643a7e991937
 F src/utf.c ee39565f0843775cc2c81135751ddd93eceb91a673ea2c57f61c76f288b041a0
 F src/util.c 602fe229f32a96ceccae4f40824129669582096f7c355f53dbac156c9fecef23
 F src/vacuum.c 6c38ddc52f0619865c91dae9c441d4d48bf3040d7dc1bc5b22da1e45547ed0b3
-F src/vdbe.c b1830c6daf744473a732257652b6431ac18032f508a3e30ff3a1466fe5978559
+F src/vdbe.c af4a5e9d64dbcc484be1fa4609b655577f81ee2cd40b61e96bece6d43718ae91
 F src/vdbe.h a1d0e3b934e835e73edd146f2e7c4eadb711b5c9875c18159a57483fd78e550e
 F src/vdbeInt.h 8dd91427155a38ec06e9ecbde07e33f21bc02e101625191e7613f883e379a363
-F src/vdbeapi.c bc3812dff7c9e6497c87ae86962818a51f66f8d7a873e7ec02a22aa115b84799
+F src/vdbeapi.c 299da88f2788ac50b83890bbcfcfbfd09f5863604ad66f6165010cd897d087b5
 F src/vdbeaux.c 1de06d17a1af1bf5cc776e60afcc01c49438df90863fc4db0a0516060e7b959a
 F src/vdbeblob.c 5e61ce31aca17db8fb60395407457a8c1c7fb471dde405e0cd675974611dcfcd
-F src/vdbemem.c dc02c6b8d51bcfc50f02266cb7003395d2989b72a9df6be561fcecdf16040784
+F src/vdbemem.c d6add1f60a255bd513b2b66a4139e810a8060bfe3d0639c34a0b80923d00ef35
 F src/vdbesort.c 43756031ca7430f7aec3ef904824a7883c4ede783e51f280d99b9b65c0796e35
 F src/vdbetrace.c fe0bc29ebd4e02c8bc5c1945f1d2e6be5927ec12c06d89b03ef2a4def34bf823
 F src/vdbevtab.c f99b275366c5fc5e2d99f734729880994ab9500bdafde7fae3b02d562b9d323c
@@ -1945,8 +1945,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 06928e745c7bcb26ec46a17989f30efe3536fd48a74c8a1cd423cc9ff6feccb5
-R e5b296feee8b6ff8861e4cf66944c654
+P 310a3e102d8eedf92ee63ffffb48621abfb1e2736b96bd2a676d63cca0f40598
+R 36f3f4bc3d4f57fe3c73eaa6653f4db1
 U drh
-Z 8d86ba5638b23b699bb683c424e71903
+Z faba0725b64437f0f9101d235cb21291
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index 17903a1e91..ddcd1c1d29 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-310a3e102d8eedf92ee63ffffb48621abfb1e2736b96bd2a676d63cca0f40598
\ No newline at end of file
+d50b162b2f2e320af0889b931351f9443580465a933f6657fa98f437b6579277
\ No newline at end of file
diff --git a/src/vdbe.c b/src/vdbe.c
index cf6137ab0a..ec227f884a 100644
--- a/src/vdbe.c
+++ b/src/vdbe.c
@@ -7378,9 +7378,6 @@ case OP_AggFinal: {
   }
   sqlite3VdbeChangeEncoding(pMem, encoding);
   UPDATE_MAX_BLOBSIZE(pMem);
-  if( sqlite3VdbeMemTooBig(pMem) ){
-    goto too_big;
-  }
   break;
 }
 
@@ -7919,9 +7916,6 @@ case OP_VColumn: {
   REGISTER_TRACE(pOp->p3, pDest);
   UPDATE_MAX_BLOBSIZE(pDest);
 
-  if( sqlite3VdbeMemTooBig(pDest) ){
-    goto too_big;
-  }
   if( rc ) goto abort_due_to_error;
   break;
 }
@@ -8214,11 +8208,10 @@ case OP_Function: {            /* group */
     if( rc ) goto abort_due_to_error;
   }
 
-  /* Copy the result of the function into register P3 */
-  if( pOut->flags & (MEM_Str|MEM_Blob) ){
-    sqlite3VdbeChangeEncoding(pOut, encoding);
-    if( sqlite3VdbeMemTooBig(pOut) ) goto too_big;
-  }
+  assert( (pOut->flags&MEM_Str)==0 
+       || pOut->enc==encoding
+       || db->mallocFailed );
+  assert( !sqlite3VdbeMemTooBig(pOut) );
 
   REGISTER_TRACE(pOp->p3, pOut);
   UPDATE_MAX_BLOBSIZE(pOut);
diff --git a/src/vdbeapi.c b/src/vdbeapi.c
index af1e94487c..48487694b2 100644
--- a/src/vdbeapi.c
+++ b/src/vdbeapi.c
@@ -378,7 +378,8 @@ static void setResultStrOrError(
   u8 enc,                 /* Encoding of z.  0 for BLOBs */
   void (*xDel)(void*)     /* Destructor function */
 ){
-  int rc = sqlite3VdbeMemSetStr(pCtx->pOut, z, n, enc, xDel);
+  Mem *pOut = pCtx->pOut;
+  int rc = sqlite3VdbeMemSetStr(pOut, z, n, enc, xDel);
   if( rc ){
     if( rc==SQLITE_TOOBIG ){
       sqlite3_result_error_toobig(pCtx);
@@ -388,6 +389,13 @@ static void setResultStrOrError(
       assert( rc==SQLITE_NOMEM );
       sqlite3_result_error_nomem(pCtx);
     }
+    return;
+  }
+  if( pOut->enc!=ENC(pOut->db) ){
+    sqlite3VdbeChangeEncoding(pOut, ENC(pOut->db));
+    if( sqlite3VdbeMemTooBig(pOut) ){
+      sqlite3_result_error_toobig(pCtx);
+    }
   }
 }
 static int invokeValueDestructor(
@@ -531,17 +539,22 @@ void sqlite3_result_text16le(
 }
 #endif /* SQLITE_OMIT_UTF16 */
 void sqlite3_result_value(sqlite3_context *pCtx, sqlite3_value *pValue){
+  Mem *pOut = pCtx->pOut;
   assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
-  sqlite3VdbeMemCopy(pCtx->pOut, pValue);
+  sqlite3VdbeMemCopy(pOut, pValue);
+  sqlite3VdbeChangeEncoding(pOut, ENC(pOut->db));
+  if( sqlite3VdbeMemTooBig(pOut) ){
+    sqlite3_result_error_toobig(pCtx);
+  }
 }
 void sqlite3_result_zeroblob(sqlite3_context *pCtx, int n){
-  assert( sqlite3_mutex_held(pCtx->pOut->db->mutex) );
-  sqlite3VdbeMemSetZeroBlob(pCtx->pOut, n);
+  sqlite3_result_zeroblob64(pCtx, n>0 ? n : 0);
 }
 int sqlite3_result_zeroblob64(sqlite3_context *pCtx, u64 n){
   Mem *pOut = pCtx->pOut;
   assert( sqlite3_mutex_held(pOut->db->mutex) );
   if( n>(u64)pOut->db->aLimit[SQLITE_LIMIT_LENGTH] ){
+    sqlite3_result_error_toobig(pCtx);
     return SQLITE_TOOBIG;
   }
 #ifndef SQLITE_OMIT_INCRBLOB
@@ -557,8 +570,8 @@ void sqlite3_result_error_code(sqlite3_context *pCtx, int errCode){
   if( pCtx->pVdbe ) pCtx->pVdbe->rcApp = errCode;
 #endif
   if( pCtx->pOut->flags & MEM_Null ){
-    sqlite3VdbeMemSetStr(pCtx->pOut, sqlite3ErrStr(errCode), -1, 
-                         SQLITE_UTF8, SQLITE_STATIC);
+    setResultStrOrError(pCtx, sqlite3ErrStr(errCode), -1, SQLITE_UTF8,
+                        SQLITE_STATIC);
   }
 }
 
diff --git a/src/vdbemem.c b/src/vdbemem.c
index 524280e0df..7a736fc21b 100644
--- a/src/vdbemem.c
+++ b/src/vdbemem.c
@@ -204,7 +204,11 @@ int sqlite3VdbeChangeEncoding(Mem *pMem, int desiredEnc){
   assert( !sqlite3VdbeMemIsRowSet(pMem) );
   assert( desiredEnc==SQLITE_UTF8 || desiredEnc==SQLITE_UTF16LE
            || desiredEnc==SQLITE_UTF16BE );
-  if( !(pMem->flags&MEM_Str) || pMem->enc==desiredEnc ){
+  if( pMem->enc==desiredEnc ){
+    return SQLITE_OK;
+  }
+  if( !(pMem->flags&MEM_Str) ){
+    pMem->enc = desiredEnc;
     return SQLITE_OK;
   }
   assert( pMem->db==0 || sqlite3_mutex_held(pMem->db->mutex) );
@@ -1152,12 +1156,7 @@ int sqlite3VdbeMemSetStr(
     flags= MEM_Str|MEM_Term;
   }else if( enc==0 ){
     flags = MEM_Blob;
-#ifdef SQLITE_ENABLE_SESSION
-    enc = pMem->db ? ENC(pMem->db) : SQLITE_UTF8;
-#else
-    assert( pMem->db!=0 );
-    enc = ENC(pMem->db);
-#endif
+    enc = SQLITE_UTF8;
   }else{
     flags = MEM_Str;
   }
@@ -1205,10 +1204,7 @@ int sqlite3VdbeMemSetStr(
   pMem->enc = enc;
 
 #ifndef SQLITE_OMIT_UTF16
-  if( enc>SQLITE_UTF8
-   && (flags & MEM_Blob)==0
-   && sqlite3VdbeMemHandleBom(pMem)
-  ){
+  if( enc>SQLITE_UTF8 && sqlite3VdbeMemHandleBom(pMem) ){
     return SQLITE_NOMEM_BKPT;
   }
 #endif