From: drh <drh@noemail.net>
Date: Mon, 5 Nov 2018 23:01:45 +0000 (+0000)
Subject: Initial code to make shadow tables read-only to ordinary SQL. The now
X-Git-Tag: version-3.26.0~47^2~12
X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=84c501bac16576916840daffb671b72cf1f75625;p=thirdparty%2Fsqlite.git

Initial code to make shadow tables read-only to ordinary SQL. The now
xShadowName method is added to the sqlite3_module object and is used
to identify potential shadow tables.  The SQLITE_PREPARE_SHADOW argument
to sqlite3_prepare_v3() is defined.  It is designed to permit writing to
shadow tables, but is currently an unused placeholder.

FossilOrigin-Name: 31942b3dd3f66eb0d9977bf1cadc2f2d7be7967cce2b55784be0b939dfef1985
---

diff --git a/ext/expert/sqlite3expert.c b/ext/expert/sqlite3expert.c
index 695aaece8c..e88fb7e78c 100644
--- a/ext/expert/sqlite3expert.c
+++ b/ext/expert/sqlite3expert.c
@@ -644,6 +644,7 @@ static int idxRegisterVtab(sqlite3expert *p){
     0,                            /* xSavepoint */
     0,                            /* xRelease */
     0,                            /* xRollbackTo */
+    0,                            /* xShadowName */
   };
 
   return sqlite3_create_module(p->dbv, "expert", &expertModule, (void*)p);
diff --git a/ext/fts3/fts3.c b/ext/fts3/fts3.c
index 3897054c7c..5899d4f244 100644
--- a/ext/fts3/fts3.c
+++ b/ext/fts3/fts3.c
@@ -3846,8 +3846,23 @@ static int fts3RollbackToMethod(sqlite3_vtab *pVtab, int iSavepoint){
   return SQLITE_OK;
 }
 
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int fts3ShadowName(const char *zName){
+  static const char *azName[] = {
+    "content", "docsize", "segdir", "segments", "stat", 
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
 static const sqlite3_module fts3Module = {
-  /* iVersion      */ 2,
+  /* iVersion      */ 3,
   /* xCreate       */ fts3CreateMethod,
   /* xConnect      */ fts3ConnectMethod,
   /* xBestIndex    */ fts3BestIndexMethod,
@@ -3870,6 +3885,7 @@ static const sqlite3_module fts3Module = {
   /* xSavepoint    */ fts3SavepointMethod,
   /* xRelease      */ fts3ReleaseMethod,
   /* xRollbackTo   */ fts3RollbackToMethod,
+  /* xShadowName   */ fts3ShadowName,
 };
 
 /*
diff --git a/ext/fts3/fts3_aux.c b/ext/fts3/fts3_aux.c
index f85a48ae02..54aea6f789 100644
--- a/ext/fts3/fts3_aux.c
+++ b/ext/fts3/fts3_aux.c
@@ -539,7 +539,8 @@ int sqlite3Fts3InitAux(sqlite3 *db){
      0,                           /* xRename       */
      0,                           /* xSavepoint    */
      0,                           /* xRelease      */
-     0                            /* xRollbackTo   */
+     0,                           /* xRollbackTo   */
+     0                            /* xShadowName   */
   };
   int rc;                         /* Return code */
 
diff --git a/ext/fts3/fts3_term.c b/ext/fts3/fts3_term.c
index 7edd072892..aaa2404279 100644
--- a/ext/fts3/fts3_term.c
+++ b/ext/fts3/fts3_term.c
@@ -361,7 +361,8 @@ int sqlite3Fts3InitTerm(sqlite3 *db){
      0,                           /* xRename       */
      0,                           /* xSavepoint    */
      0,                           /* xRelease      */
-     0                            /* xRollbackTo   */
+     0,                           /* xRollbackTo   */
+     0                            /* xShadowName   */
   };
   int rc;                         /* Return code */
 
diff --git a/ext/fts3/fts3_tokenize_vtab.c b/ext/fts3/fts3_tokenize_vtab.c
index dfeddfeb96..a3d24bc676 100644
--- a/ext/fts3/fts3_tokenize_vtab.c
+++ b/ext/fts3/fts3_tokenize_vtab.c
@@ -443,7 +443,8 @@ int sqlite3Fts3InitTok(sqlite3 *db, Fts3Hash *pHash){
      0,                           /* xRename       */
      0,                           /* xSavepoint    */
      0,                           /* xRelease      */
-     0                            /* xRollbackTo   */
+     0,                           /* xRollbackTo   */
+     0                            /* xShadowName   */
   };
   int rc;                         /* Return code */
 
diff --git a/ext/fts3/fts3_write.c b/ext/fts3/fts3_write.c
index 8fc6589121..01ff53d4d3 100644
--- a/ext/fts3/fts3_write.c
+++ b/ext/fts3/fts3_write.c
@@ -407,7 +407,8 @@ static int fts3SqlStmt(
     if( !zSql ){
       rc = SQLITE_NOMEM;
     }else{
-      rc = sqlite3_prepare_v3(p->db, zSql, -1, SQLITE_PREPARE_PERSISTENT,
+      rc = sqlite3_prepare_v3(p->db, zSql, -1,
+                              SQLITE_PREPARE_PERSISTENT | SQLITE_PREPARE_SHADOW,
                               &pStmt, NULL);
       sqlite3_free(zSql);
       assert( rc==SQLITE_OK || pStmt==0 );
diff --git a/ext/fts5/fts5_index.c b/ext/fts5/fts5_index.c
index 394280b3f2..e4c13751f5 100644
--- a/ext/fts5/fts5_index.c
+++ b/ext/fts5/fts5_index.c
@@ -729,7 +729,8 @@ static int fts5IndexPrepareStmt(
   if( p->rc==SQLITE_OK ){
     if( zSql ){
       p->rc = sqlite3_prepare_v3(p->pConfig->db, zSql, -1,
-                                 SQLITE_PREPARE_PERSISTENT, ppStmt, 0);
+                                SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_SHADOW,
+                                ppStmt, 0);
     }else{
       p->rc = SQLITE_NOMEM;
     }
@@ -780,7 +781,8 @@ static void fts5DataDelete(Fts5Index *p, i64 iFirst, i64 iLast){
       rc = SQLITE_NOMEM;
     }else{
       rc = sqlite3_prepare_v3(pConfig->db, zSql, -1,
-                              SQLITE_PREPARE_PERSISTENT, &p->pDeleter, 0);
+                              SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_SHADOW,
+                              &p->pDeleter, 0);
       sqlite3_free(zSql);
     }
     if( rc!=SQLITE_OK ){
diff --git a/ext/fts5/fts5_main.c b/ext/fts5/fts5_main.c
index e9ec2de3a4..41c1c45eb0 100644
--- a/ext/fts5/fts5_main.c
+++ b/ext/fts5/fts5_main.c
@@ -890,7 +890,8 @@ static int fts5PrepareStatement(
     rc = SQLITE_NOMEM; 
   }else{
     rc = sqlite3_prepare_v3(pConfig->db, zSql, -1, 
-                            SQLITE_PREPARE_PERSISTENT, &pRet, 0);
+                            SQLITE_PREPARE_PERSISTENT |SQLITE_PREPARE_SHADOW,
+                            &pRet, 0);
     if( rc!=SQLITE_OK ){
       *pConfig->pzErrmsg = sqlite3_mprintf("%s", sqlite3_errmsg(pConfig->db));
     }
@@ -2645,9 +2646,24 @@ static void fts5SourceIdFunc(
   sqlite3_result_text(pCtx, "--FTS5-SOURCE-ID--", -1, SQLITE_TRANSIENT);
 }
 
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int fts5ShadowName(const char *zName){
+  static const char *azName[] = {
+    "config", "content", "data", "docsize", "idx"
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
 static int fts5Init(sqlite3 *db){
   static const sqlite3_module fts5Mod = {
-    /* iVersion      */ 2,
+    /* iVersion      */ 3,
     /* xCreate       */ fts5CreateMethod,
     /* xConnect      */ fts5ConnectMethod,
     /* xBestIndex    */ fts5BestIndexMethod,
@@ -2670,6 +2686,7 @@ static int fts5Init(sqlite3 *db){
     /* xSavepoint    */ fts5SavepointMethod,
     /* xRelease      */ fts5ReleaseMethod,
     /* xRollbackTo   */ fts5RollbackToMethod,
+    /* xShadowName   */ fts5ShadowName
   };
 
   int rc;
diff --git a/ext/fts5/fts5_storage.c b/ext/fts5/fts5_storage.c
index 70d7135113..2bdc4703b9 100644
--- a/ext/fts5/fts5_storage.c
+++ b/ext/fts5/fts5_storage.c
@@ -137,7 +137,8 @@ static int fts5StorageGetStmt(
       rc = SQLITE_NOMEM;
     }else{
       rc = sqlite3_prepare_v3(pC->db, zSql, -1,
-                              SQLITE_PREPARE_PERSISTENT, &p->aStmt[eStmt], 0);
+                              SQLITE_PREPARE_PERSISTENT|SQLITE_PREPARE_SHADOW,
+                              &p->aStmt[eStmt], 0);
       sqlite3_free(zSql);
       if( rc!=SQLITE_OK && pzErrMsg ){
         *pzErrMsg = sqlite3_mprintf("%s", sqlite3_errmsg(pC->db));
diff --git a/ext/fts5/fts5_test_tok.c b/ext/fts5/fts5_test_tok.c
index 1818e16790..6f71e6534d 100644
--- a/ext/fts5/fts5_test_tok.c
+++ b/ext/fts5/fts5_test_tok.c
@@ -471,7 +471,8 @@ int sqlite3Fts5TestRegisterTok(sqlite3 *db, fts5_api *pApi){
      0,                           /* xRename       */
      0,                           /* xSavepoint    */
      0,                           /* xRelease      */
-     0                            /* xRollbackTo   */
+     0,                           /* xRollbackTo   */
+     0                            /* xShadowName   */
   };
   int rc;                         /* Return code */
 
diff --git a/ext/fts5/fts5_vocab.c b/ext/fts5/fts5_vocab.c
index 27f2ff3b2c..c1b64249a4 100644
--- a/ext/fts5/fts5_vocab.c
+++ b/ext/fts5/fts5_vocab.c
@@ -755,10 +755,9 @@ int sqlite3Fts5VocabInit(Fts5Global *pGlobal, sqlite3 *db){
     /* xSavepoint    */ 0,
     /* xRelease      */ 0,
     /* xRollbackTo   */ 0,
+    /* xShadowName   */ 0
   };
   void *p = (void*)pGlobal;
 
   return sqlite3_create_module_v2(db, "fts5vocab", &fts5Vocab, p, 0);
 }
-
-
diff --git a/ext/misc/amatch.c b/ext/misc/amatch.c
index 914e2633d4..142e354f28 100644
--- a/ext/misc/amatch.c
+++ b/ext/misc/amatch.c
@@ -1473,7 +1473,8 @@ static sqlite3_module amatchModule = {
   0,                      /* xRename */
   0,                      /* xSavepoint */
   0,                      /* xRelease */
-  0                       /* xRollbackTo */
+  0,                      /* xRollbackTo */
+  0                       /* xShadowName */
 };
 
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
diff --git a/ext/misc/btreeinfo.c b/ext/misc/btreeinfo.c
index 131b210a79..3d818f20c0 100644
--- a/ext/misc/btreeinfo.c
+++ b/ext/misc/btreeinfo.c
@@ -411,6 +411,7 @@ int sqlite3BinfoRegister(sqlite3 *db){
     0,                           /* xSavepoint */
     0,                           /* xRelease */
     0,                           /* xRollbackTo */
+    0                            /* xShadowName */
   };
   return sqlite3_create_module(db, "sqlite_btreeinfo", &binfo_module, 0);
 }
diff --git a/ext/misc/closure.c b/ext/misc/closure.c
index 74bffc7708..03f13c0c79 100644
--- a/ext/misc/closure.c
+++ b/ext/misc/closure.c
@@ -938,7 +938,8 @@ static sqlite3_module closureModule = {
   0,                      /* xRename */
   0,                      /* xSavepoint */
   0,                      /* xRelease */
-  0                       /* xRollbackTo */
+  0,                      /* xRollbackTo */
+  0                       /* xShadowName */
 };
 
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
diff --git a/ext/misc/completion.c b/ext/misc/completion.c
index 4a4b918a37..72ad23df93 100644
--- a/ext/misc/completion.c
+++ b/ext/misc/completion.c
@@ -468,7 +468,8 @@ static sqlite3_module completionModule = {
   0,                         /* xRename */
   0,                         /* xSavepoint */
   0,                         /* xRelease */
-  0                          /* xRollbackTo */
+  0,                         /* xRollbackTo */
+  0                          /* xShadowName */
 };
 
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
diff --git a/ext/misc/explain.c b/ext/misc/explain.c
index b228440f58..dc0c9d7669 100644
--- a/ext/misc/explain.c
+++ b/ext/misc/explain.c
@@ -280,6 +280,7 @@ static sqlite3_module explainModule = {
   0,                         /* xSavepoint */
   0,                         /* xRelease */
   0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
 };
 
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
diff --git a/ext/misc/fileio.c b/ext/misc/fileio.c
index 816a353c6e..e3e22ea4b0 100644
--- a/ext/misc/fileio.c
+++ b/ext/misc/fileio.c
@@ -888,7 +888,8 @@ static int fsdirRegister(sqlite3 *db){
     0,                         /* xRename */
     0,                         /* xSavepoint */
     0,                         /* xRelease */
-    0                          /* xRollbackTo */
+    0,                         /* xRollbackTo */
+    0,                         /* xShadowName */
   };
 
   int rc = sqlite3_create_module(db, "fsdir", &fsdirModule, 0);
diff --git a/ext/misc/json1.c b/ext/misc/json1.c
index 85b1143f83..7cff3d28d8 100644
--- a/ext/misc/json1.c
+++ b/ext/misc/json1.c
@@ -2388,7 +2388,8 @@ static sqlite3_module jsonEachModule = {
   0,                         /* xRename */
   0,                         /* xSavepoint */
   0,                         /* xRelease */
-  0                          /* xRollbackTo */
+  0,                         /* xRollbackTo */
+  0                          /* xShadowName */
 };
 
 /* The methods of the json_tree virtual table. */
@@ -2415,7 +2416,8 @@ static sqlite3_module jsonTreeModule = {
   0,                         /* xRename */
   0,                         /* xSavepoint */
   0,                         /* xRelease */
-  0                          /* xRollbackTo */
+  0,                         /* xRollbackTo */
+  0                          /* xShadowName */
 };
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
 
diff --git a/ext/misc/memstat.c b/ext/misc/memstat.c
index 3194e752cc..dcd5742fd2 100644
--- a/ext/misc/memstat.c
+++ b/ext/misc/memstat.c
@@ -395,6 +395,7 @@ static sqlite3_module memstatModule = {
   0,                         /* xSavepoint */
   0,                         /* xRelease */
   0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
 };
 
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
diff --git a/ext/misc/stmt.c b/ext/misc/stmt.c
index dbaa0bd64d..d2b33e7416 100644
--- a/ext/misc/stmt.c
+++ b/ext/misc/stmt.c
@@ -266,6 +266,7 @@ static sqlite3_module stmtModule = {
   0,                         /* xSavepoint */
   0,                         /* xRelease */
   0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
 };
 
 #endif /* SQLITE_OMIT_VIRTUALTABLE */
diff --git a/ext/misc/templatevtab.c b/ext/misc/templatevtab.c
index 95b5f60cab..d7efa2b40e 100644
--- a/ext/misc/templatevtab.c
+++ b/ext/misc/templatevtab.c
@@ -248,7 +248,8 @@ static sqlite3_module templatevtabModule = {
   /* xRename     */ 0,
   /* xSavepoint  */ 0,
   /* xRelease    */ 0,
-  /* xRollbackTo */ 0
+  /* xRollbackTo */ 0,
+  /* xShadowName */ 0
 };
 
 
diff --git a/ext/misc/unionvtab.c b/ext/misc/unionvtab.c
index 94a5c8f013..2d2053ce9a 100644
--- a/ext/misc/unionvtab.c
+++ b/ext/misc/unionvtab.c
@@ -1350,7 +1350,8 @@ static int createUnionVtab(sqlite3 *db){
     0,                            /* xRename */
     0,                            /* xSavepoint */
     0,                            /* xRelease */
-    0                             /* xRollbackTo */
+    0,                            /* xRollbackTo */
+    0                             /* xShadowName */
   };
   int rc;
 
diff --git a/ext/misc/vtablog.c b/ext/misc/vtablog.c
index 9e03fd455d..424b3457ff 100644
--- a/ext/misc/vtablog.c
+++ b/ext/misc/vtablog.c
@@ -492,6 +492,7 @@ static sqlite3_module vtablogModule = {
   0,                         /* xSavepoint */
   0,                         /* xRelease */
   0,                         /* xRollbackTo */
+  0,                         /* xShadowName */
 };
 
 #ifdef _WIN32
diff --git a/ext/rtree/geopoly.c b/ext/rtree/geopoly.c
index be582a3e1b..4ac3b0aa2f 100644
--- a/ext/rtree/geopoly.c
+++ b/ext/rtree/geopoly.c
@@ -1725,7 +1725,7 @@ static int geopolyFindFunction(
 
 
 static sqlite3_module geopolyModule = {
-  2,                          /* iVersion */
+  3,                          /* iVersion */
   geopolyCreate,              /* xCreate - create a table */
   geopolyConnect,             /* xConnect - connect to an existing table */
   geopolyBestIndex,           /* xBestIndex - Determine search strategy */
@@ -1748,6 +1748,7 @@ static sqlite3_module geopolyModule = {
   rtreeSavepoint,             /* xSavepoint */
   0,                          /* xRelease */
   0,                          /* xRollbackTo */
+  rtreeShadowName             /* xShadowName */
 };
 
 static int sqlite3_geopoly_init(sqlite3 *db){
diff --git a/ext/rtree/rtree.c b/ext/rtree/rtree.c
index c00648f6a2..fd1abef1ec 100644
--- a/ext/rtree/rtree.c
+++ b/ext/rtree/rtree.c
@@ -3325,8 +3325,24 @@ static int rtreeQueryStat1(sqlite3 *db, Rtree *pRtree){
   return rc;
 }
 
+
+/*
+** Return true if zName is the extension on one of the shadow tables used
+** by this module.
+*/
+static int rtreeShadowName(const char *zName){
+  static const char *azName[] = {
+    "node", "parent", "rowid"
+  };
+  unsigned int i;
+  for(i=0; i<sizeof(azName)/sizeof(azName[0]); i++){
+    if( sqlite3_stricmp(zName, azName[i])==0 ) return 1;
+  }
+  return 0;
+}
+
 static sqlite3_module rtreeModule = {
-  2,                          /* iVersion */
+  3,                          /* iVersion */
   rtreeCreate,                /* xCreate - create a table */
   rtreeConnect,               /* xConnect - connect to an existing table */
   rtreeBestIndex,             /* xBestIndex - Determine search strategy */
@@ -3349,6 +3365,7 @@ static sqlite3_module rtreeModule = {
   rtreeSavepoint,             /* xSavepoint */
   0,                          /* xRelease */
   0,                          /* xRollbackTo */
+  rtreeShadowName             /* xShadowName */
 };
 
 static int rtreeSqlInit(
@@ -3434,7 +3451,8 @@ static int rtreeSqlInit(
     }
     zSql = sqlite3_mprintf(zFormat, zDb, zPrefix);
     if( zSql ){
-      rc = sqlite3_prepare_v3(db, zSql, -1, SQLITE_PREPARE_PERSISTENT,
+      rc = sqlite3_prepare_v3(db, zSql, -1,
+                              SQLITE_PREPARE_PERSISTENT | SQLITE_PREPARE_SHADOW,
                               appStmt[i], 0); 
     }else{
       rc = SQLITE_NOMEM;
diff --git a/manifest b/manifest
index d225e86d86..f7cb0936e7 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\sthe\sSQLITE_DBCONFIG_DEFENSIVE\sflag.
-D 2018-11-05T19:37:30.613
+C Initial\scode\sto\smake\sshadow\stables\sread-only\sto\sordinary\sSQL.\sThe\snow\nxShadowName\smethod\sis\sadded\sto\sthe\ssqlite3_module\sobject\sand\sis\sused\nto\sidentify\spotential\sshadow\stables.\s\sThe\sSQLITE_PREPARE_SHADOW\sargument\nto\ssqlite3_prepare_v3()\sis\sdefined.\s\sIt\sis\sdesigned\sto\spermit\swriting\sto\nshadow\stables,\sbut\sis\scurrently\san\sunused\splaceholder.
+D 2018-11-05T23:01:45.801
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in edbb6e20bb1decf65f6c64c9e61004a69bdf8afb39cdce5337c916b03dfcd1e3
@@ -47,7 +47,7 @@ F ext/async/sqlite3async.h f489b080af7e72aec0e1ee6f1d98ab6cf2e4dcef
 F ext/expert/README.md b321c2762bb93c18ea102d5a5f7753a4b8bac646cb392b3b437f633caf2020c3
 F ext/expert/expert.c d548d603a4cc9e61f446cc179c120c6713511c413f82a4a32b1e1e69d3f086a4
 F ext/expert/expert1.test 333d037021c901322f9afc4a5687648ea23d56f1a0a079358a390664babf01be
-F ext/expert/sqlite3expert.c 89b7b59be610b929958db02416539a46ac088fd84f81623c4190aff62e92c3c4
+F ext/expert/sqlite3expert.c 3da865f2286433588260f41e796422c611bceaca3a0bbf9139a619cf7d062c19
 F ext/expert/sqlite3expert.h af6354f8ee5c9e025024e63fec3bd640a802afcc3099a44d804752cf0791d811
 F ext/expert/test_expert.c d56c194b769bdc90cf829a14c9ecbc1edca9c850b837a4d0b13be14095c32a72
 F ext/fts1/README.txt 20ac73b006a70bcfd80069bdaf59214b6cf1db5e
@@ -80,25 +80,25 @@ F ext/fts3/README.content fdc666a70d5257a64fee209f97cf89e0e6e32b51
 F ext/fts3/README.syntax a19711dc5458c20734b8e485e75fb1981ec2427a
 F ext/fts3/README.tokenizers e0a8b81383ea60d0334d274fadf305ea14a8c314
 F ext/fts3/README.txt 8c18f41574404623b76917b9da66fcb0ab38328d
-F ext/fts3/fts3.c 012384f01df28345a8d0d0c7fe465ab211598a91d78a7331b3664533756ed9fa
+F ext/fts3/fts3.c eddaba472f7ceee0240252e21875547bd137d4383fcd9e6c99b9e59078356171
 F ext/fts3/fts3.h 3a10a0af180d502cecc50df77b1b22df142817fe
 F ext/fts3/fts3Int.h 3378157f383540857a466420b8279626204434c3eb0dc948ad9bcd3991fc41f5
-F ext/fts3/fts3_aux.c 9edc3655fcb287f0467d0a4b886a01c6185fe9f1
+F ext/fts3/fts3_aux.c e9b465f8469acc2cd700a90c0242912a3202e4e4e15df72d7db7f1e3a2222c85
 F ext/fts3/fts3_expr.c 3b1dbceddd8622599f3cc2626897667fe40487aaa1676707d6c37ec5a8422fc1
 F ext/fts3/fts3_hash.c 29b986e43f4e9dd40110eafa377dc0d63c422c60
 F ext/fts3/fts3_hash.h 39cf6874dc239d6b4e30479b1975fe5b22a3caaf
 F ext/fts3/fts3_icu.c deb46f7020d87ea7a14a433fb7a7f4bef42a9652
 F ext/fts3/fts3_porter.c 3565faf04b626cddf85f03825e86056a4562c009
 F ext/fts3/fts3_snippet.c 68ae118b0f834ea53d2b89e4087fc0f0b8c4ee4e
-F ext/fts3/fts3_term.c 88c55a6fa1a51ab494e33dced0401a6c28791fd7
+F ext/fts3/fts3_term.c 9b8065cc70ad514fcc25a7b099ddab8b5333f724dedd57184b7e79238e2b2a39
 F ext/fts3/fts3_test.c 79f2a7fbb3f672fa032e5a432ca274ea3ee93c34
-F ext/fts3/fts3_tokenize_vtab.c a27593ab19657166f6fa5ec073b678cc29a75860
+F ext/fts3/fts3_tokenize_vtab.c a47c2a33de6db00816704315ac0a9afdfa1c71fa5b99f79171c0f7b30861f784
 F ext/fts3/fts3_tokenizer.c a22bf311a71f3efa9d7012d8cc48fc9b0f3dace7
 F ext/fts3/fts3_tokenizer.h 64c6ef6c5272c51ebe60fc607a896e84288fcbc3
 F ext/fts3/fts3_tokenizer1.c 5c98225a53705e5ee34824087478cf477bdb7004
 F ext/fts3/fts3_unicode.c 525a3bd9a7564603c5c061b7de55403a565307758a94600e8a2f6b00d1c40d9d
 F ext/fts3/fts3_unicode2.c cc04fc672bfd42b1e650398cb0bf71f64f9aae032cfe75bbcfe75b9cf966029c
-F ext/fts3/fts3_write.c a85bc4885fde7f1b44c9de013b62f7cd3332dc59e208053d878729b1d04745bc
+F ext/fts3/fts3_write.c 0031c455ddd9a65cb840dbb844d5d4391cd0324007f43fed1fec2bc782dc0bd2
 F ext/fts3/fts3speed.tcl b54caf6a18d38174f1a6e84219950d85e98bb1e9
 F ext/fts3/mkfts3amal.tcl 252ecb7fe6467854f2aa237bf2c390b74e71f100
 F ext/fts3/tool/fts3cov.sh c331d006359456cf6f8f953e37f2b9c7d568f3863f00bb5f7eb87fea4ac01b73
@@ -115,16 +115,16 @@ F ext/fts5/fts5_buffer.c 1dd1ec0446b3acfc2d7d407eb894762a461613e2695273f48e449bf
 F ext/fts5/fts5_config.c 5af9c360e99669d29f06492c370892394aba0857
 F ext/fts5/fts5_expr.c 5aef080ba3c8947e22f38ce1ff9fe548e4a740e72b77241f35ed941ae128d2c7
 F ext/fts5/fts5_hash.c 32be400cf761868c9db33efe81a06eb19a17c5402ad477ee9efb51301546dd55
-F ext/fts5/fts5_index.c d1b2d7d92cb2b72b9465da35b7d7c30e4b426c7f208bf6f94ce86b50eed8a1cb
-F ext/fts5/fts5_main.c 7e52868e6b444e5353ff30e1dcd2a9273e8eaa543ddccf0c94b3cd2c235ff104
-F ext/fts5/fts5_storage.c 4bec8a1b3905978b22a67bca5f4a3cfdb94af234cf51efb36f4f2d733d278634
+F ext/fts5/fts5_index.c ddaea9e164670f4c2d97441da9b11499718114a8920f49f1982eb6a6c06863fa
+F ext/fts5/fts5_main.c 5318b205988edf3fcce615182cbe29bd507ccb69a80e1c96f9f9a743db4394b9
+F ext/fts5/fts5_storage.c d35ccef429923a381eb39d834b14c8dc8a86eb0d1bab936f37b3adc3ad84f763
 F ext/fts5/fts5_tcl.c 39bcbae507f594aad778172fa914cad0f585bf92fd3b078c686e249282db0d95
 F ext/fts5/fts5_test_mi.c 65864ba1e5c34a61d409c4c587e0bbe0466eb4f8f478d85dc42a92caad1338e6
-F ext/fts5/fts5_test_tok.c ffd657dd67e7fcdb31bf63fb60b6d867299a581d0f46e97086abacd66c2a9b26
+F ext/fts5/fts5_test_tok.c 80de1a4b1a3caa216c3be8862440f0117a8357dd9b7cfc5a2a2ce11fe6eb64ae
 F ext/fts5/fts5_tokenize.c ebd13d034f3dc7c841e1c32c364a4fca5cc2e05a0b91682a93fa1e6defcd4292
 F ext/fts5/fts5_unicode2.c 543cf0987c27ad59e5a7a6222480b917b5431009b7b139027c9581a63e39e37e
 F ext/fts5/fts5_varint.c a5aceacda04dafcbae725413d7a16818ecd65738
-F ext/fts5/fts5_vocab.c 1cd79854cb21543e66507b25b0578bc1b20aa6a1349b7feceb8e8fed0e7a77a6
+F ext/fts5/fts5_vocab.c dfe3bfc7ccd39ef7d149c1828b6663995e580e9b315de029801be62d2b72bedd
 F ext/fts5/fts5parse.y eb526940f892ade5693f22ffd6c4f2702543a9059942772526eac1fde256bb05
 F ext/fts5/mkportersteps.tcl 5acf962d2e0074f701620bb5308155fa1e4a63ba
 F ext/fts5/test/fts5_common.tcl b01c584144b5064f30e6c648145a2dd6bc440841
@@ -270,23 +270,23 @@ F ext/lsm1/test/lsm1_common.tcl 5ed4bab07c93be2e4f300ebe46007ecf4b3e20bc5fbe1ded
 F ext/lsm1/test/lsm1_simple.test ca949efefa102f4644231dcd9291d8cda7699a4ce1006b26e0e3fcb72233f422
 F ext/lsm1/tool/mklsm1c.tcl f31561bbee5349f0a554d1ad7236ac1991fc09176626f529f6078e07335398b0
 F ext/misc/README.md d6dd0fe1d8af77040216798a6a2b0c46c73054d2f0ea544fbbcdccf6f238c240
-F ext/misc/amatch.c 6db4607cb17c54b853a2d7c7c36046d004853f65b9b733e6f019d543d5dfae87
+F ext/misc/amatch.c c0a6a807a553eaa220bf69fca0353cd1587a3bfb3d2224fa425e3e6efcacc98a
 F ext/misc/anycollseq.c 5ffdfde9829eeac52219136ad6aa7cd9a4edb3b15f4f2532de52f4a22525eddb
 F ext/misc/appendvfs.c 3777f22ec1057dc4e5fd89f2fbddcc7a29fbeef1ad038c736c54411bb1967af7
-F ext/misc/btreeinfo.c 78c8c57d325185ccc04b7679e5b020e34a4d9c87453e6b7ac943d0a26cee3256
+F ext/misc/btreeinfo.c 4f0ebf278f46e68e6306c667917766cebc5550fd35d5de17847988e22892d4d2
 F ext/misc/carray.c ed96c218ea940b85c9a274c4d9c59fe9491c299147a38a8bba537687bd6c6005
-F ext/misc/closure.c fe928228e8dfb2f00227311c203ccba9c2e5561f4f6de6da87e5b4a30cd8af15
-F ext/misc/completion.c fc811dda86d899c15848079c32cad40c181da1dd7a1a4f8d768a2c6ce07a1904
+F ext/misc/closure.c 9f8fa11aa6c6e2f6d7296ffa88f103df4b46abd9602bcab3ea2f8fc24f334f63
+F ext/misc/completion.c cec672d40604075bb341a7f11ac48393efdcd90a979269b8fe7977ea62d0547f
 F ext/misc/compress.c dd4f8a6d0baccff3c694757db5b430f3bbd821d8686d1fc24df55cf9f035b189
 F ext/misc/csv.c 65297bcce8d5acd5aadef42acbe739aef5a2ef5e74c7b73361ca19f3e21de657
 F ext/misc/dbdump.c 12389a10c410fadf1e68eeb382def92d5a7fa9ce7cce4fb86a736fa2bac1000a
 F ext/misc/eval.c 6ea9b22a5fa0dd973b67ca4e53555be177bc0b7b263aadf1024429457c82c0e3
-F ext/misc/explain.c 5851a1a4a1bba6e078da4103fcafc84aa54adfd8edbba419f5cf1eba9f000d50
-F ext/misc/fileio.c 7317d825fab6a3c48f6e3822a00a6a22e08e55af31700ac96f16a523f83069fd
+F ext/misc/explain.c c82dd86f1156d32b284e0523a4bf6a93a85ab2a812caed48963e0774f3327185
+F ext/misc/fileio.c 70f933c2e530bdceb35fbf4fe529fc1bdcdd26454c77cf8c4bc456c4123e612b
 F ext/misc/fuzzer.c 7c64b8197bb77b7d64eff7cac7848870235d4c25
 F ext/misc/ieee754.c f190d0cc5182529acb15babd177781be1ac1718c
-F ext/misc/json1.c 276f87dc8365b34b0fffb7ef32481dd07fac6fdb3224e2822396a48377ac8363
-F ext/misc/memstat.c 7542ff1dd1d926e63dab904070e689cd5b47e4dd19498ad31947c42b207f5363
+F ext/misc/json1.c b0fba11c4f4e7c80534b08e120a296a8b301ee7e4d1a33f6647f1c047c8ce8e2
+F ext/misc/memstat.c 941928c6104d8ed569a6c47caa756dc78b8091f7a15f87d3004f3b1e576b10da
 F ext/misc/memvfs.c ab36f49e02ebcdf85a1e08dc4d8599ea8f343e073ac9e0bca18a98b7e1ec9567
 F ext/misc/mmapwarm.c 70b618f2d0bde43fae288ad0b7498a629f2b6f61b50a27e06fae3cd23c83af29
 F ext/misc/nextchar.c 35c8b8baacb96d92abbb34a83a997b797075b342
@@ -302,13 +302,13 @@ F ext/misc/shathree.c 22ba7ca84a433d6466a7d05dcc876910b435a715da8cc462517db93514
 F ext/misc/showauth.c 732578f0fe4ce42d577e1c86dc89dd14a006ab52
 F ext/misc/spellfix.c f88ecb2c0294453ce8b7704b211f5350c41b085b38c8e056852e3a08b0f5e484
 F ext/misc/sqlar.c 57d5bc45cd5492208e451f697404be88f8612527d64c9d42f96b325b64983d74
-F ext/misc/stmt.c 6f16443abb3551e3f5813bb13ba19a30e7032830015b0f92fe0c0453045c0a11
-F ext/misc/templatevtab.c 8251b31011dd00fc38e739c78c234c930be42b3b274bbe0493b79cd40db02a9e
+F ext/misc/stmt.c 8a8dc4675042e4551e4afe99b8d0cc7a4a2fc1a8dacc0a9ce1b1bbff145da93d
+F ext/misc/templatevtab.c 8a16a91a5ceaccfcbd6aaaa56d46828806e460dd194965b3f77bf38f14b942c4
 F ext/misc/totype.c 4a167594e791abeed95e0a8db028822b5e8fe512
-F ext/misc/unionvtab.c 0b3173f69b8899da640a13a345dc5ef1400199405f738abe6145b2454195b8ff
+F ext/misc/unionvtab.c acf947858054850db2d4a611bfeae072cdc6d9f517b46a993fe1f2f1ea20031e
 F ext/misc/vfslog.c fe40fab5c077a40477f7e5eba994309ecac6cc95
 F ext/misc/vfsstat.c bf10ef0bc51e1ad6756629e1edb142f7a8db1178
-F ext/misc/vtablog.c 31d0d8f4406795679dcd3a67917c213d3a2a5fb3ea5de35f6e773491ed7e13c9
+F ext/misc/vtablog.c 5538acd0c8ddaae372331bee11608d76973436b77d6a91e8635cfc9432fba5ae
 F ext/misc/vtshim.c 1976e6dd68dd0d64508c91a6dfab8e75f8aaf6cd
 F ext/misc/wholenumber.c 784b12543d60702ebdd47da936e278aa03076212
 F ext/misc/zipfile.c c4de8f0ad446ce4a49aae11ff7b771cd7af60d7136c0bcfb53da1475b9075e79
@@ -361,8 +361,8 @@ F ext/repair/test/checkfreelist01.test 3e8aa6aeb4007680c94a8d07b41c339aa635cc782
 F ext/repair/test/checkindex01.test 6945d0ffc0c1dc993b2ce88036b26e0f5d6fcc65da70fc9df27c2647bb358b0f
 F ext/repair/test/test.tcl 686d76d888dffd021f64260abf29a55c57b2cedfa7fc69150b42b1d6119aac3c
 F ext/rtree/README 6315c0d73ebf0ec40dedb5aa0e942bc8b54e3761
-F ext/rtree/geopoly.c 2464b3325fcc2878ed08458efeb995f830f4eef28bbf3da9757c4bd95e6f9549
-F ext/rtree/rtree.c 6cc2e673cf1e9ea1619f13ab990f12389dfb951b131acbc2fbe164cee8992a20
+F ext/rtree/geopoly.c 38ad90cab8dbd3dfba246d642f47366e40418e47fa55fe89f1078483d51b52c0
+F ext/rtree/rtree.c 8367dc4a71968767b2909f3b651905e3d11e22a24340f16b82763a2e08bd991f
 F ext/rtree/rtree.h 4a690463901cb5e6127cf05eb8e642f127012fd5003830dbc974eca5802d9412
 F ext/rtree/rtree1.test 309afc04d4287542b2cd74f933296832cc681c7b014d9405cb329b62053a5349
 F ext/rtree/rtree2.test 5f25b01acd03470067a2d52783b2eb0a50bf836803d4342d20ca39e541220fe2
@@ -448,13 +448,13 @@ F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
 F src/btree.c 3ef104ecae8b1b5f0458be1f5fa7c1ecf25fdc322a9d63bb8151f89eb32d381e
 F src/btree.h febb2e817be499570b7a2e32a9bbb4b607a9234f6b84bb9ae84916d4806e96f2
 F src/btreeInt.h 620ab4c7235f43572cf3ac2ac8723cbdf68073be4d29da24897c7b77dda5fd96
-F src/build.c a614b226b9af1e49ec6d0ffbf3aa0d38a73123336a7f78930005db939d038253
+F src/build.c 3b611e7da095f2c4ff470c7368355be9c9c8e15fc234cb00eeea7c233108b2f2
 F src/callback.c 789bd33d188146f66c0dd8306472a72d1c05f71924b24a91caf6bd45cf9aba73
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 109e58d00f62e8e71ee1eb5944ac18b90171c928ab2e082e058056e1137cc20b
 F src/date.c ebe1dc7c8a347117bb02570f1a931c62dd78f4a2b1b516f4837d45b7d6426957
-F src/dbpage.c ada9bc6964bb68e4c128df70cb0938faaa214e1a0e1d730ea6b13c5e1fde9a45
-F src/dbstat.c e042b0e7833fdacf2d5ea92c6b536962fea6aeed8b7287ca87ddfa3412bd9564
+F src/dbpage.c cfa87c8a9e3b5267a72faa3a592a497cd3810146c056c53a3472caf763c8556b
+F src/dbstat.c 9ad3f2d9d19a915d414870b9405b19493eed41975f3ad0d13f70fdd0831853b4
 F src/delete.c e1ac11c062a4a2ed29a9e9a63f4cbc7f0330291ae276d768b26fb2c5152cc3b4
 F src/expr.c 9aacc0b72348ba90010b672dcbbbe2fa56e1182043bc917a3a147b2bc57a5497
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
@@ -497,7 +497,7 @@ F src/parse.y 6840fe7c0b5eb4dd25ee5d075213bc8255ed4c0678d71bfb6744d0520d91c179
 F src/pcache.c 4196eb6ed3bbf00b80596c8e0b4f50e57eb7d890c19fb27a7354306abb7f983d
 F src/pcache.h 072f94d29281cffd99e46c1539849f248c4b56ae7684c1f36626797fee375170
 F src/pcache1.c 716975564c15eb6679e97f734cec1bfd6c16ac3d4010f05f1f8e509fc7d19880
-F src/pragma.c 0bb05b1788d7af5fdc7f40f5655a79a140dece8fd2523402eb2103925e4739c2
+F src/pragma.c 3a5f39517cbe90af3271fb5dd2866a50fbcf4ced6cb464dcc80a6f763b415206
 F src/pragma.h fdd03d78a7497f74a3f652909f945328480089189526841ae829ce7313d98d13
 F src/prepare.c f81f8d707e583192c28fea0b2e19385415b7d188123b23f49b038076408d7a69
 F src/printf.c 0f1177cf1dd4d7827bf64d840768514ec76409abecaca9e8b577dbd065150381
@@ -506,10 +506,10 @@ F src/resolve.c bc8c79e56439b111e7d9415e44940951f7087e9466c3a9d664558ef0faf31073
 F src/rowset.c d977b011993aaea002cab3e0bb2ce50cf346000dff94e944d547b989f4b1fe93
 F src/select.c 61e867a906f140b73baf4ce7a201ad6dcba30820969f5618ee40e9a0d32c6f5f
 F src/shell.c.in 060ccc327959bdc85c895015eb382017fd0cd000ebd47b7e8dda42f8aab0b66f
-F src/sqlite.h.in 1383b2fbce61bd3634caeafb2513205326a297e988ea749d4f6dec7da7a281c9
+F src/sqlite.h.in 612b5d40927cce9047413eaedd2f5a662b6360d08b00091c4213b30411c0fcbe
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 960f1b86c3610fa23cb6a267572a97dcf286e77aa0dd3b9b23292ffaa1ea8683
-F src/sqliteInt.h 8aef40f6e756120d51de73537dbdcd624f2b2b028fc59baad85e38a83e35d838
+F src/sqliteInt.h 7a6bbb9a8864af66d864eb4e4619e263b44a35b8604f6775e1e226133d14d5ef
 F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
 F src/status.c 46e7aec11f79dad50965a5ca5fa9de009f7d6bde08be2156f1538a0a296d4d0e
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@@ -1776,8 +1776,10 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P b8d35c4a7c99ce3753761e5b81269d52c3c910c603fa70b72549883ba68bc485 76094345821246c887a31a234b339d03a78eddbb9fab33b06c3c20797c038349
-R 926c099479c1d3f76ac3c956522bfabe
-T +closed 76094345821246c887a31a234b339d03a78eddbb9fab33b06c3c20797c038349
+P 11d98414eac467affb0b3cf0c7e5cc3d43184fc2b6e7e898bb5277b51ea9e1fa
+R b572c18296089d812924dea7e0530e89
+T *branch * read-only-shadow
+T *sym-read-only-shadow *
+T -sym-trunk *
 U drh
-Z 58f19e654e2db3cbbf8bd66e3b3e9711
+Z dcee1f2a6fee8069f27c592b55f8069d
diff --git a/manifest.uuid b/manifest.uuid
index 768477b0a3..dfe15a5876 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-11d98414eac467affb0b3cf0c7e5cc3d43184fc2b6e7e898bb5277b51ea9e1fa
\ No newline at end of file
+31942b3dd3f66eb0d9977bf1cadc2f2d7be7967cce2b55784be0b939dfef1985
\ No newline at end of file
diff --git a/src/build.c b/src/build.c
index 0f62116770..3f425d6fc2 100644
--- a/src/build.c
+++ b/src/build.c
@@ -1894,6 +1894,35 @@ static void convertToWithoutRowidTable(Parse *pParse, Table *pTab){
   recomputeColumnsNotIndexed(pPk);
 }
 
+/*
+** Return true if zName is a shadow table name in the current database
+** connection.
+**
+** zName is temporarily modified while this routine is running, but is
+** restored to its original value prior to this routine returning.
+*/
+static int isShadowTableName(sqlite3 *db, char *zName){
+  char *zTail;                  /* Pointer to the last "_" in zName */
+  Table *pTab;                  /* Table that zName is a shadow of */
+  VTable *pVTab;                /* Virtual table corresponding to pTab */
+  const sqlite3_module *pMod;   /* module methods for pVTab */
+  zTail = strrchr(zName, '_');
+  if( zTail==0 ) return 0;
+  *zTail = 0;
+  pTab = sqlite3FindTable(db, zName, 0);
+  *zTail = '_';
+  if( pTab==0 ) return 0;
+  if( !IsVirtual(pTab) ) return 0;
+  pVTab = sqlite3GetVTable(db, pTab);
+  if( pVTab==0 ) return 0;
+  if( pVTab->pMod==0 ) return 0;
+  pMod = pVTab->pMod->pModule;
+  assert( pMod!=0 );
+  if( pMod->iVersion<3 ) return 0;
+  if( pMod->xShadowName==0 ) return 0;
+  return pMod->xShadowName(zTail+1);
+}
+
 /*
 ** This routine is called to report the final ")" that terminates
 ** a CREATE TABLE statement.
@@ -1933,6 +1962,10 @@ void sqlite3EndTable(
   p = pParse->pNewTable;
   if( p==0 ) return;
 
+  if( pSelect==0 && isShadowTableName(db, p->zName) ){
+    p->tabFlags |= TF_Shadow;
+  }
+
   /* If the db->init.busy is 1 it means we are reading the SQL off the
   ** "sqlite_master" or "sqlite_temp_master" table on the disk.
   ** So do not write to the disk again.  Extract the root page number
diff --git a/src/dbpage.c b/src/dbpage.c
index a73ea01bdb..4f46659018 100644
--- a/src/dbpage.c
+++ b/src/dbpage.c
@@ -407,6 +407,7 @@ int sqlite3DbpageRegister(sqlite3 *db){
     0,                            /* xSavepoint */
     0,                            /* xRelease */
     0,                            /* xRollbackTo */
+    0                             /* xShadowName */
   };
   return sqlite3_create_module(db, "sqlite_dbpage", &dbpage_module, 0);
 }
diff --git a/src/dbstat.c b/src/dbstat.c
index ca0d541013..a2c6fe0894 100644
--- a/src/dbstat.c
+++ b/src/dbstat.c
@@ -720,6 +720,7 @@ int sqlite3DbstatRegister(sqlite3 *db){
     0,                            /* xSavepoint */
     0,                            /* xRelease */
     0,                            /* xRollbackTo */
+    0                             /* xShadowName */
   };
   return sqlite3_create_module(db, "dbstat", &dbstat_module, 0);
 }
diff --git a/src/pragma.c b/src/pragma.c
index 52d6338ca0..20656dc453 100644
--- a/src/pragma.c
+++ b/src/pragma.c
@@ -2477,7 +2477,8 @@ static const sqlite3_module pragmaVtabModule = {
   0,                           /* xRename - rename the table */
   0,                           /* xSavepoint */
   0,                           /* xRelease */
-  0                            /* xRollbackTo */
+  0,                           /* xRollbackTo */
+  0                            /* xShadowName */
 };
 
 /*
diff --git a/src/sqlite.h.in b/src/sqlite.h.in
index 18593a6440..02963f4542 100644
--- a/src/sqlite.h.in
+++ b/src/sqlite.h.in
@@ -3642,10 +3642,19 @@ int sqlite3_limit(sqlite3*, int id, int newVal);
 ** normalize a SQL statement are unspecified and subject to change.
 ** At a minimum, literal values will be replaced with suitable
 ** placeholders.
+**
+** [[SQLITE_PREPARE_SHADOW]] ^(<dt>SQLITE_PREPARE_SHADOW</dt>
+** <dd>When the SQLITE_PREPARE_SHADOW flag is set, writes to shadow
+** tables are allowed.  Shadow tables are ordinary tables associated
+** with some virtual tables that serve as the storage for the virtual
+** table.  Shadow tables are normally read-only.  Virtual table
+** implementations use this flag so that they can write to their own
+** shadow tables.
 ** </dl>
 */
 #define SQLITE_PREPARE_PERSISTENT              0x01
 #define SQLITE_PREPARE_NORMALIZE               0x02
+#define SQLITE_PREPARE_SHADOW                  0x04
 
 /*
 ** CAPI3REF: Compiling An SQL Statement
@@ -6322,6 +6331,9 @@ struct sqlite3_module {
   int (*xSavepoint)(sqlite3_vtab *pVTab, int);
   int (*xRelease)(sqlite3_vtab *pVTab, int);
   int (*xRollbackTo)(sqlite3_vtab *pVTab, int);
+  /* The methods above are in versions 1 and 2 of the sqlite_module object.
+  ** Those below are for version 3 and greater. */
+  int (*xShadowName)(const char*);
 };
 
 /*
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 27caa1ace6..053ac01dc3 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -2001,6 +2001,7 @@ struct Table {
 #define TF_StatsUsed       0x0100    /* Query planner decisions affected by
                                      ** Index.aiRowLogEst[] values */
 #define TF_HasNotNull      0x0200    /* Contains NOT NULL constraints */
+#define TF_Shadow          0x0400    /* True for a shadow table */
 
 /*
 ** Test to see whether or not a table is a virtual table.  This is