Reduce the size of the SrcItem object by combining fields into a union.

FossilOrigin-Name: a4c59ac3c6ec979c25b544d29e47b8e39f6439c098eed8f84b3bd506c9adf047

10 files changed, 71 insertions, 42 deletions

diff --git a/src/attach.c b/src/attach.c
index 4a6a25bf0..65b492474 100644
--- a/src/attach.c
+++ b/src/attach.c
@@ -480,19 +480,20 @@ static int fixSelectCb(Walker *p, Select *pSelect){
   if( NEVER(pList==0) ) return WRC_Continue;
   for(i=0, pItem=pList->a; i<pList->nSrc; i++, pItem++){
     if( pFix->bTemp==0 ){
-      if( pItem->zDatabase ){
-        if( iDb!=sqlite3FindDbName(db, pItem->zDatabase) ){
+      if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+        if( iDb!=sqlite3FindDbName(db, pItem->u4.zDatabase) ){
           sqlite3ErrorMsg(pFix->pParse,
               "%s %T cannot reference objects in database %s",
-              pFix->zType, pFix->pName, pItem->zDatabase);
+              pFix->zType, pFix->pName, pItem->u4.zDatabase);
           return WRC_Abort;
         }
-        sqlite3DbFree(db, pItem->zDatabase);
-        pItem->zDatabase = 0;
+        sqlite3DbFree(db, pItem->u4.zDatabase);
         pItem->fg.notCte = 1;
+        pItem->fg.hadSchema = 1;
       }
-      pItem->pSchema = pFix->pSchema;
+      pItem->u4.pSchema = pFix->pSchema;
       pItem->fg.fromDDL = 1;
+      pItem->fg.fixedSchema = 1;
     }
 #if !defined(SQLITE_OMIT_VIEW) || !defined(SQLITE_OMIT_TRIGGER)
     if( pList->a[i].fg.isUsing==0
diff --git a/src/build.c b/src/build.c
index 9747810e8..a0c4b493f 100644
--- a/src/build.c
+++ b/src/build.c
@@ -497,12 +497,11 @@ Table *sqlite3LocateTableItem(
   SrcItem *p
 ){
   const char *zDb;
-  assert( p->pSchema==0 || p->zDatabase==0 );
-  if( p->pSchema ){
-    int iDb = sqlite3SchemaToIndex(pParse->db, p->pSchema);
+  if( p->fg.fixedSchema ){
+    int iDb = sqlite3SchemaToIndex(pParse->db, p->u4.pSchema);
     zDb = pParse->db->aDb[iDb].zDbSName;
   }else{
-    zDb = p->zDatabase;
+    zDb = p->u4.zDatabase;
   }
   return sqlite3LocateTable(pParse, flags, p->zName, zDb);
 }
@@ -3487,6 +3486,7 @@ void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
   }
   assert( pParse->nErr==0 );
   assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 );
   if( sqlite3ReadSchema(pParse) ) goto exit_drop_table;
   if( noErr ) db->suppressErr++;
   assert( isView==0 || isView==LOCATE_VIEW );
@@ -3495,7 +3495,7 @@ void sqlite3DropTable(Parse *pParse, SrcList *pName, int isView, int noErr){
 
   if( pTab==0 ){
     if( noErr ){
-      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].u4.zDatabase);
       sqlite3ForceNotReadOnly(pParse);
     }
     goto exit_drop_table;
@@ -4586,15 +4586,16 @@ void sqlite3DropIndex(Parse *pParse, SrcList *pName, int ifExists){
   }
   assert( pParse->nErr==0 );   /* Never called with prior non-OOM errors */
   assert( pName->nSrc==1 );
+  assert( pName->a[0].fg.fixedSchema==0 );
   if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
     goto exit_drop_index;
   }
-  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].zDatabase);
+  pIndex = sqlite3FindIndex(db, pName->a[0].zName, pName->a[0].u4.zDatabase);
   if( pIndex==0 ){
     if( !ifExists ){
       sqlite3ErrorMsg(pParse, "no such index: %S", pName->a);
     }else{
-      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].zDatabase);
+      sqlite3CodeVerifyNamedSchema(pParse, pName->a[0].u4.zDatabase);
       sqlite3ForceNotReadOnly(pParse);
     }
     pParse->checkSchema = 1;
@@ -4891,12 +4892,13 @@ SrcList *sqlite3SrcListAppend(
   if( pDatabase && pDatabase->z==0 ){
     pDatabase = 0;
   }
+  assert( pItem->fg.fixedSchema==0 );
   if( pDatabase ){
     pItem->zName = sqlite3NameFromToken(db, pDatabase);
-    pItem->zDatabase = sqlite3NameFromToken(db, pTable);
+    pItem->u4.zDatabase = sqlite3NameFromToken(db, pTable);
   }else{
     pItem->zName = sqlite3NameFromToken(db, pTable);
-    pItem->zDatabase = 0;
+    pItem->u4.zDatabase = 0;
   }
   return pList;
 }
@@ -4928,9 +4930,11 @@ void sqlite3SrcListDelete(sqlite3 *db, SrcList *pList){
   assert( db!=0 );
   if( pList==0 ) return;
   for(pItem=pList->a, i=0; i<pList->nSrc; i++, pItem++){
-    if( pItem->zDatabase ) sqlite3DbNNFreeNN(db, pItem->zDatabase);
     if( pItem->zName ) sqlite3DbNNFreeNN(db, pItem->zName);
     if( pItem->zAlias ) sqlite3DbNNFreeNN(db, pItem->zAlias);
+    if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+      sqlite3DbNNFreeNN(db, pItem->u4.zDatabase);
+    }
     if( pItem->fg.isIndexedBy ) sqlite3DbFree(db, pItem->u1.zIndexedBy);
     if( pItem->fg.isTabFunc ) sqlite3ExprListDelete(db, pItem->u1.pFuncArg);
     sqlite3DeleteTable(db, pItem->pTab);
diff --git a/src/delete.c b/src/delete.c
index 2baff5b3d..bc7a7a3f5 100644
--- a/src/delete.c
+++ b/src/delete.c
@@ -156,7 +156,8 @@ void sqlite3MaterializeView(
   if( pFrom ){
     assert( pFrom->nSrc==1 );
     pFrom->a[0].zName = sqlite3DbStrDup(db, pView->zName);
-    pFrom->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+    assert( pFrom->a[0].fg.fixedSchema==0 );
+    pFrom->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
     assert( pFrom->a[0].fg.isUsing==0 );
     assert( pFrom->a[0].u3.pOn==0 );
   }
diff --git a/src/expr.c b/src/expr.c
index 53b0170ab..d0fa4b500 100644
--- a/src/expr.c
+++ b/src/expr.c
@@ -1877,8 +1877,11 @@ SrcList *sqlite3SrcListDup(sqlite3 *db, const SrcList *p, int flags){
     SrcItem *pNewItem = &pNew->a[i];
     const SrcItem *pOldItem = &p->a[i];
     Table *pTab;
-    pNewItem->pSchema = pOldItem->pSchema;
-    pNewItem->zDatabase = sqlite3DbStrDup(db, pOldItem->zDatabase);
+    if( pOldItem->fg.fixedSchema ){
+      pNewItem->u4.pSchema = pOldItem->u4.pSchema;
+    }else{
+      pNewItem->u4.zDatabase = sqlite3DbStrDup(db, pOldItem->u4.zDatabase);
+    }
     pNewItem->zName = sqlite3DbStrDup(db, pOldItem->zName);
     pNewItem->zAlias = sqlite3DbStrDup(db, pOldItem->zAlias);
     pNewItem->fg = pOldItem->fg;
diff --git a/src/fkey.c b/src/fkey.c
index 1efdc0bba..c68037a65 100644
--- a/src/fkey.c
+++ b/src/fkey.c
@@ -1337,7 +1337,8 @@ static Trigger *fkActionTrigger(
       if( pSrc ){
         assert( pSrc->nSrc==1 );
         pSrc->a[0].zName = sqlite3DbStrDup(db, zFrom);
-        pSrc->a[0].zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
+        assert( pSrc->a[0].fg.fixedSchema==0 );
+        pSrc->a[0].u4.zDatabase = sqlite3DbStrDup(db, db->aDb[iDb].zDbSName);
       }
       pSelect = sqlite3SelectNew(pParse, 
           sqlite3ExprListAppend(pParse, 0, pRaise),
diff --git a/src/parse.y b/src/parse.y
index 68c00f0a7..a605ad691 100644
--- a/src/parse.y
+++ b/src/parse.y
@@ -740,8 +740,9 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
       if( A ){
         SrcItem *pNew = &A->a[A->nSrc-1];
         SrcItem *pOld = F->a;
+        assert( pOld->fg.fixedSchema==0 );
         pNew->zName = pOld->zName;
-        pNew->zDatabase = pOld->zDatabase;
+        pNew->u4.zDatabase = pOld->u4.zDatabase;
         pNew->pSelect = pOld->pSelect;
         if( pNew->pSelect && (pNew->pSelect->selFlags & SF_NestedFrom)!=0 ){
           pNew->fg.isNestedFrom = 1;
@@ -752,7 +753,7 @@ seltablist(A) ::= stl_prefix(A) nm(Y) dbnm(D) LP exprlist(E) RP as(Z) on_using(N
           pOld->fg.isTabFunc = 0;
           pNew->fg.isTabFunc = 1;
         }
-        pOld->zName = pOld->zDatabase = 0;
+        pOld->zName = pOld->u4.zDatabase = 0;
         pOld->pSelect = 0;
       }
       sqlite3SrcListDelete(pParse->db, F);
diff --git a/src/printf.c b/src/printf.c
index c0dcc5d0f..12dd91a78 100644
--- a/src/printf.c
+++ b/src/printf.c
@@ -848,8 +848,8 @@ void sqlite3_str_vappendf(
         if( pItem->zAlias && !flag_altform2 ){
           sqlite3_str_appendall(pAccum, pItem->zAlias);
         }else if( pItem->zName ){
-          if( pItem->zDatabase ){
-            sqlite3_str_appendall(pAccum, pItem->zDatabase);
+          if( pItem->fg.fixedSchema==0 && pItem->u4.zDatabase!=0 ){
+            sqlite3_str_appendall(pAccum, pItem->u4.zDatabase);
             sqlite3_str_append(pAccum, ".", 1);
           }
           sqlite3_str_appendall(pAccum, pItem->zName);
diff --git a/src/select.c b/src/select.c
index 4b0b55429..634f06e30 100644
--- a/src/select.c
+++ b/src/select.c
@@ -4506,10 +4506,12 @@ static int flattenSubquery(
 
   /* Delete the transient structures associated with the subquery */
   pSub1 = pSubitem->pSelect;
-  sqlite3DbFree(db, pSubitem->zDatabase);
+  if( pSubitem->fg.fixedSchema==0 ){
+    sqlite3DbFree(db, pSubitem->u4.zDatabase);
+    pSubitem->u4.zDatabase = 0;
+  }
   sqlite3DbFree(db, pSubitem->zName);
   sqlite3DbFree(db, pSubitem->zAlias);
-  pSubitem->zDatabase = 0;
   pSubitem->zName = 0;
   pSubitem->zAlias = 0;
   pSubitem->pSelect = 0;
@@ -5637,7 +5639,7 @@ static struct Cte *searchWith(
 ){
   const char *zName = pItem->zName;
   With *p;
-  assert( pItem->zDatabase==0 );
+  assert( pItem->fg.fixedSchema || pItem->u4.zDatabase==0 );
   assert( zName!=0 );
   for(p=pWith; p; p=p->pOuter){
     int i;
@@ -5717,7 +5719,8 @@ static int resolveFromTermToCte(
     ** go no further. */
     return 0;
   }
-  if( pFrom->zDatabase!=0 ){
+  assert( pFrom->fg.hadSchema==0 || pFrom->fg.notCte!=0 );
+  if( pFrom->fg.fixedSchema==0 && pFrom->u4.zDatabase!=0 ){
     /* The FROM term contains a schema qualifier (ex: main.t1) and so
     ** it cannot possibly be a CTE reference. */
     return 0;
@@ -5794,7 +5797,8 @@ static int resolveFromTermToCte(
       assert( pRecTerm->pPrior!=0 );
       for(i=0; i<pSrc->nSrc; i++){
         SrcItem *pItem = &pSrc->a[i];
-        if( pItem->zDatabase==0
+        if( ((pItem->fg.fixedSchema==0 && pItem->u4.zDatabase==0)
+             || pItem->fg.hadSchema==0)
          && pItem->zName!=0
          && 0==sqlite3StrICmp(pItem->zName, pCte->zName)
         ){
@@ -7681,7 +7685,14 @@ int sqlite3Select(
     ** string for the fake column name seems safer.
     */
     if( pItem->colUsed==0 && pItem->zName!=0 ){
-      sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, "", pItem->zDatabase);
+      const char *zDb;
+      if( pItem->fg.fixedSchema ){
+        int iDb = sqlite3SchemaToIndex(pParse->db, pItem->u4.pSchema);
+        zDb = db->aDb[iDb].zDbSName;
+      }else{
+        zDb = pItem->u4.zDatabase;
+      }
+      sqlite3AuthCheck(pParse, SQLITE_READ, pItem->zName, "", zDb);
     }
 
 #if !defined(SQLITE_OMIT_SUBQUERY) || !defined(SQLITE_OMIT_VIEW)
diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index ebd0f01b2..75e1f6120 100644
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -3297,13 +3297,11 @@ struct IdList {
 **    u2.pCteUse         fg.isCte       && !fg.isIndexedBy
 */
 struct SrcItem {
-  Schema *pSchema;  /* Schema to which this item is fixed */
-  char *zDatabase;  /* Name of database holding this table */
   char *zName;      /* Name of the table */
   char *zAlias;     /* The "B" part of a "A AS B" phrase.  zName is the "A" */
   Table *pTab;      /* An SQL table corresponding to zName */
   Select *pSelect;  /* A SELECT statement used in place of a table name */
-  int addrFillSub;  /* Address of subroutine to manifest a subquery */
+  int addrFillSub;  /* Address of subroutine to initialize a subquery */
   int regReturn;    /* Register holding return address of addrFillSub */
   int regResult;    /* Registers holding results of a co-routine */
   struct {
@@ -3323,12 +3321,10 @@ struct SrcItem {
     unsigned isSynthUsing :1;  /* u3.pUsing is synthesized from NATURAL */
     unsigned isNestedFrom :1;  /* pSelect is a SF_NestedFrom subquery */
     unsigned rowidUsed :1;     /* The ROWID of this table is referenced */
+    unsigned fixedSchema :1;   /* Uses u4.pSchema, not u4.zDatabase */
+    unsigned hadSchema :1;     /* Has u4.zDatabase before u4.pSchema */
   } fg;
   int iCursor;      /* The VDBE cursor number used to access this table */
-  union {
-    Expr *pOn;        /* fg.isUsing==0 =>  The ON clause of a join */
-    IdList *pUsing;   /* fg.isUsing==1 =>  The USING clause of a join */
-  } u3;
   Bitmask colUsed;  /* Bit N set if column N used. Details above for N>62 */
   union {
     char *zIndexedBy;    /* Identifier from "INDEXED BY <zIndex>" clause */
@@ -3339,6 +3335,14 @@ struct SrcItem {
     Index *pIBIndex;  /* Index structure corresponding to u1.zIndexedBy */
     CteUse *pCteUse;  /* CTE Usage info when fg.isCte is true */
   } u2;
+  union {
+    Expr *pOn;        /* fg.isUsing==0 =>  The ON clause of a join */
+    IdList *pUsing;   /* fg.isUsing==1 =>  The USING clause of a join */
+  } u3;
+  union {
+    Schema *pSchema;  /* Schema to which this item is fixed */
+    char *zDatabase;  /* Name of database holding this table */
+  } u4;
 };
 
 /*
diff --git a/src/trigger.c b/src/trigger.c
index 98e8da58c..a5a57abf1 100644
--- a/src/trigger.c
+++ b/src/trigger.c
@@ -151,9 +151,9 @@ void sqlite3BeginTrigger(
   ** To maintain backwards compatibility, ignore the database
   ** name on pTableName if we are reparsing out of the schema table
   */
-  if( db->init.busy && iDb!=1 ){
-    sqlite3DbFree(db, pTableName->a[0].zDatabase);
-    pTableName->a[0].zDatabase = 0;
+  if( db->init.busy && iDb!=1 && ALWAYS(pTableName->a[0].fg.fixedSchema==0) ){
+    sqlite3DbFree(db, pTableName->a[0].u4.zDatabase);
+    pTableName->a[0].u4.zDatabase = 0;
   }
 
   /* If the trigger name was unqualified, and the table is a temp table,
@@ -631,7 +631,8 @@ void sqlite3DropTrigger(Parse *pParse, SrcList *pName, int noErr){
   }
 
   assert( pName->nSrc==1 );
-  zDb = pName->a[0].zDatabase;
+  assert( pName->a[0].fg.fixedSchema==0 );
+  zDb = pName->a[0].u4.zDatabase;
   zName = pName->a[0].zName;
   assert( zDb!=0 || sqlite3BtreeHoldsAllMutexes(db) );
   for(i=OMIT_TEMPDB; i<db->nDb; i++){
@@ -868,7 +869,9 @@ SrcList *sqlite3TriggerStepSrc(
     Schema *pSchema = pStep->pTrig->pSchema;
     pSrc->a[0].zName = zName;
     if( pSchema!=db->aDb[1].pSchema ){
-      pSrc->a[0].pSchema = pSchema;
+      assert( pSrc->a[0].fg.fixedSchema || pSrc->a[0].u4.zDatabase==0 );
+      pSrc->a[0].u4.pSchema = pSchema;
+      pSrc->a[0].fg.fixedSchema = 1;
     }
     if( pStep->pFrom ){
       SrcList *pDup = sqlite3SrcListDup(db, pStep->pFrom, 0);