Avoid many unnecessary calls to sqlite3ReadSchema() and sqlite3Init() when

the schema is known to be valid already.

FossilOrigin-Name: 58cf812fd81329e82b3fdd61b7ad2040c9b90d2d80f592b9231e0e1902c8d577

diff --git a/manifest b/manifest
index cffde9d974d6e2518df45d7fedd4ce5c7639e8a4..b3f7180c63648984f4767633dff771e3ea6b5dcc 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Add\san\sassert()\sto\sensure\sthat\sschema\smutexes\sare\sheld\sprior\sto\saccessing\nthe\sDB_SchemaLoaded\sflag\sinside\sof\ssqlite3Init().
-D 2018-04-25T10:30:46.214
+C Avoid\smany\sunnecessary\scalls\sto\ssqlite3ReadSchema()\sand\ssqlite3Init()\swhen\nthe\sschema\sis\sknown\sto\sbe\svalid\salready.
+D 2018-04-25T12:01:45.412
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in 5ce9343cba9c189046f1afe6d2bcc1f68079439febc05267b98aec6ecc752439
@@ -428,15 +428,15 @@ F sqlite3.1 fc7ad8990fc8409983309bb80de8c811a7506786
 F sqlite3.pc.in 48fed132e7cb71ab676105d2a4dc77127d8c1f3a
 F src/alter.c cf7a8af45cb0ace672f47a1b29ab24092a9e8cd8d945a9974e3b5d925f548594
 F src/analyze.c 71fbbeb7b25417592f54d869fe90c28b48e4cecb9926ef9b06d90fb0aec48941
-F src/attach.c f2ed3224c0dc44f934c4edf232238bd29b7bd8b325532c0f541857bf0e12faaa
+F src/attach.c 4a3138bd771d5426ae4344d8d5e900440af29fabc5ec2f39f69a45010dfbccd7
 F src/auth.c 6277d63837357549fe14e723490d6dc1a38768d71c795c5eb5c0f8a99f918f73
 F src/backup.c faf17e60b43233c214aae6a8179d24503a61e83b
 F src/bitvec.c 17ea48eff8ba979f1f5b04cc484c7bb2be632f33
-F src/btmutex.c 0e9ce2d56159b89b9bc8e197e023ee11e39ff8ca
+F src/btmutex.c 8acc2f464ee76324bf13310df5692a262b801808984c1b79defb2503bbafadb6
 F src/btree.c 9eb9531c65346bbfccf5325384b7db1849daf4db6601dcfe21ba5c5b20623b64
 F src/btree.h 0866c0a08255142ea0e754aabd211c843cab32045c978a592a43152405ed0c84
 F src/btreeInt.h 620ab4c7235f43572cf3ac2ac8723cbdf68073be4d29da24897c7b77dda5fd96
-F src/build.c 91d548027a54044851299e719d60d6a2b6eaf3e3274678098cb73a6ab8c0fa19
+F src/build.c c4227d058d52c24ffce2d33cd3a11234d8e8603901243cdb5165eddf64ee2177
 F src/callback.c fe677cb5f5abb02f7a772a62a98c2f516426081df68856e8f2d5f950929b966a
 F src/complete.c a3634ab1e687055cd002e11b8f43eb75c17da23e
 F src/ctime.c 849d4cebe008cfc6e4799b034a172b4eaf8856b100739632a852732ba66eee48
@@ -487,7 +487,7 @@ F src/pcache.h 072f94d29281cffd99e46c1539849f248c4b56ae7684c1f36626797fee375170
 F src/pcache1.c 716975564c15eb6679e97f734cec1bfd6c16ac3d4010f05f1f8e509fc7d19880
 F src/pragma.c bea56df3ae0637768c0da4fbbb8f2492f780980d95000034a105ff291bf7ca69
 F src/pragma.h bb83728944b42f6d409c77f5838a8edbdb0fe83046c5496ffc9602b40340a324
-F src/prepare.c 2243890992597ded6358121a25567efb4482369c3685692a2444ff3f46c5b434
+F src/prepare.c d16cb8a553c09bc0c46c33f8e0add77c8f755cfb4681ca5101aaff3a04df9625
 F src/printf.c d3b7844ddeb11fbbdd38dd84d09c9c1ac171d21fb038473c3aa97981201cc660
 F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
 F src/resolve.c 6415381a0e9d22c0e7cba33ca4a53f81474190862f5d4838190f5eb5b0b47bc9
@@ -497,7 +497,7 @@ F src/shell.c.in fc3f9e47198c6baea6987b6ec86fb99e7c79cee8109ce9bdece790345d8c246
 F src/sqlite.h.in aa9bd3ae4a077c7002059cb418271abe52214b0227b2a734bc44736b24cbcc40
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 83a3c4ce93d650bedfd1aa558cb85a516bd6d094445ee989740827d0d944368d
-F src/sqliteInt.h db62bdf05257d9b3950e45224c98ce36acf4da411e2923464819a56678ed21d3
+F src/sqliteInt.h c1deb023eb117b4437a69d8c5a753deb36581f1933015cd262ad32b45c4d8431
 F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
 F src/status.c 46e7aec11f79dad50965a5ca5fa9de009f7d6bde08be2156f1538a0a296d4d0e
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@@ -1725,7 +1725,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 2aa210030ae414782adab9291cc43a149a780f39bd3d306dc2892a8c20422a51
-R 445070ffd3b1be1286b1b020beb181c5
+P d8b46290bb75c695dac523cf9a50d1b43e773802e3b95fd722feca16162ab7c5
+R 214110ad6fdf7789b7b7a9c6d65bc1a8
 U drh
-Z c5a11b92ab72681e9cb438ff2daf1afb
+Z 468a9bdbe012765b3a0a759e796a254f

diff --git a/manifest.uuid b/manifest.uuid
index 8de9ce360fd662086031a332d4b835563e7220f6..e7602bf1ed2cbb69a82194d4a8087eefce640ad4 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-d8b46290bb75c695dac523cf9a50d1b43e773802e3b95fd722feca16162ab7c5
\ No newline at end of file
+58cf812fd81329e82b3fdd61b7ad2040c9b90d2d80f592b9231e0e1902c8d577
\ No newline at end of file

diff --git a/src/attach.c b/src/attach.c
index 7abdcd152e6301339d9391bc869842095555561f..ca0fd9fd1fdad1cc0c59f23d1ad468b7d877f058 100644 (file)
--- a/src/attach.c
+++ b/src/attach.c
@@ -158,7 +158,7 @@ static void attachFunc(
     sqlite3_free( zPath );
     db->nDb++;
   }
-  db->skipBtreeMutex = 0;
+  db->noSharedCache = 0;
   if( rc==SQLITE_CONSTRAINT ){
     rc = SQLITE_ERROR;
     zErrDyn = sqlite3MPrintf(db, "database is already attached");
@@ -230,6 +230,7 @@ static void attachFunc(
   if( rc==SQLITE_OK ){
     sqlite3BtreeEnterAll(db);
     db->init.iDb = 0;
+    db->mDbFlags &= ~(DBFLAG_SchemaKnownOk);
     rc = sqlite3Init(db, &zErrDyn);
     sqlite3BtreeLeaveAll(db);
     assert( zErrDyn==0 || rc!=SQLITE_OK );

diff --git a/src/btmutex.c b/src/btmutex.c
index ddffb67fa4ecf774d5da8400fa3763c5bdabff64..275a93ff21cf5e9b0c2b4d78c966fff4ab7a6e1c 100644 (file)
--- a/src/btmutex.c
+++ b/src/btmutex.c
@@ -195,10 +195,10 @@ static void SQLITE_NOINLINE btreeEnterAll(sqlite3 *db){
       skipOk = 0;
     }
   }
-  db->skipBtreeMutex = skipOk;
+  db->noSharedCache = skipOk;
 }
 void sqlite3BtreeEnterAll(sqlite3 *db){
-  if( db->skipBtreeMutex==0 ) btreeEnterAll(db);
+  if( db->noSharedCache==0 ) btreeEnterAll(db);
 }
 static void SQLITE_NOINLINE btreeLeaveAll(sqlite3 *db){
   int i;
@@ -210,7 +210,7 @@ static void SQLITE_NOINLINE btreeLeaveAll(sqlite3 *db){
   }
 }
 void sqlite3BtreeLeaveAll(sqlite3 *db){
-  if( db->skipBtreeMutex==0 ) btreeLeaveAll(db);
+  if( db->noSharedCache==0 ) btreeLeaveAll(db);
 }
 
 #ifndef NDEBUG

diff --git a/src/build.c b/src/build.c
index b032ff9f2c1ee9d8dfd07490c8abbc5b596fc5ba..9eb28572dc22ddd802e14abbe91bc84fa54a5db9 100644 (file)
--- a/src/build.c
+++ b/src/build.c
@@ -343,24 +343,27 @@ Table *sqlite3LocateTable(
   const char *zDbase     /* Name of the database.  Might be NULL */
 ){
   Table *p;
+  sqlite3 *db = pParse->db;
 
   /* Read the database schema. If an error occurs, leave an error message
   ** and code in pParse and return NULL. */
-  if( SQLITE_OK!=sqlite3ReadSchema(pParse) ){
+  if( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 
+   && SQLITE_OK!=sqlite3ReadSchema(pParse)
+  ){
     return 0;
   }
 
-  p = sqlite3FindTable(pParse->db, zName, zDbase);
+  p = sqlite3FindTable(db, zName, zDbase);
   if( p==0 ){
     const char *zMsg = flags & LOCATE_VIEW ? "no such view" : "no such table";
 #ifndef SQLITE_OMIT_VIRTUALTABLE
-    if( sqlite3FindDbName(pParse->db, zDbase)<1 ){
+    if( sqlite3FindDbName(db, zDbase)<1 ){
       /* If zName is the not the name of a table in the schema created using
       ** CREATE, then check to see if it is the name of an virtual table that
       ** can be an eponymous virtual table. */
-      Module *pMod = (Module*)sqlite3HashFind(&pParse->db->aModule, zName);
+      Module *pMod = (Module*)sqlite3HashFind(&db->aModule, zName);
       if( pMod==0 && sqlite3_strnicmp(zName, "pragma_", 7)==0 ){
-        pMod = sqlite3PragmaVtabRegister(pParse->db, zName);
+        pMod = sqlite3PragmaVtabRegister(db, zName);
       }
       if( pMod && sqlite3VtabEponymousTableInit(pParse, pMod) ){
         return pMod->pEpoTab;
@@ -525,6 +528,7 @@ void sqlite3ResetOneSchema(sqlite3 *db, int iDb){
     assert( sqlite3SchemaMutexHeld(db, iDb, 0) );
     DbSetProperty(db, iDb, DB_ResetWanted);
     DbSetProperty(db, 1, DB_ResetWanted);
+    db->mDbFlags &= ~DBFLAG_SchemaKnownOk;
   }
 
   if( db->nSchemaLock==0 ){
@@ -550,7 +554,7 @@ void sqlite3ResetAllSchemasOfConnection(sqlite3 *db){
       sqlite3SchemaClear(pDb->pSchema);
     }
   }
-  db->mDbFlags &= ~DBFLAG_SchemaChange;
+  db->mDbFlags &= ~(DBFLAG_SchemaChange|DBFLAG_SchemaKnownOk);
   sqlite3VtabUnlockList(db);
   sqlite3BtreeLeaveAll(db);
   sqlite3CollapseDatabaseArray(db);

diff --git a/src/prepare.c b/src/prepare.c
index d7cc5a9f198c1bf79cf9e3c991073eb1f33de6af..c13f88d28bc290fac5851160a1fb0b25932fedea 100644 (file)
--- a/src/prepare.c
+++ b/src/prepare.c
@@ -145,6 +145,7 @@ static int sqlite3InitOne(sqlite3 *db, int iDb, char **pzErrMsg){
   const char *zMasterName;
   int openedTransaction = 0;
 
+  assert( (db->mDbFlags & DBFLAG_SchemaKnownOk)==0 );
   assert( iDb>=0 && iDb<db->nDb );
   assert( db->aDb[iDb].pSchema );
   assert( sqlite3_mutex_held(db->mutex) );
@@ -396,10 +397,12 @@ int sqlite3ReadSchema(Parse *pParse){
   assert( sqlite3_mutex_held(db->mutex) );
   if( !db->init.busy ){
     rc = sqlite3Init(db, &pParse->zErrMsg);
-  }
-  if( rc!=SQLITE_OK ){
-    pParse->rc = rc;
-    pParse->nErr++;
+    if( rc!=SQLITE_OK ){
+      pParse->rc = rc;
+      pParse->nErr++;
+    }else if( db->noSharedCache ){
+      db->mDbFlags |= DBFLAG_SchemaKnownOk;
+    }
   }
   return rc;
 }

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 00ce823b1bbcae2495a8d519f8a189c4e52ed546..8ad15109a8ef16cc4b11954449a7ea07488741b2 100644 (file)
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1362,7 +1362,7 @@ struct sqlite3 {
   u8 vtabOnConflict;            /* Value to return for s3_vtab_on_conflict() */
   u8 isTransactionSavepoint;    /* True if the outermost savepoint is a TS */
   u8 mTrace;                    /* zero or more SQLITE_TRACE flags */
-  u8 skipBtreeMutex;            /* True if no shared-cache backends */
+  u8 noSharedCache;             /* True if no shared-cache backends */
   u8 nSqlExec;                  /* Number of pending OP_SqlExec opcodes */
   int nextPagesize;             /* Pagesize after VACUUM if >0 */
   u32 magic;                    /* Magic number for detect library misuse */
@@ -1522,6 +1522,7 @@ struct sqlite3 {
 #define DBFLAG_SchemaChange   0x0001  /* Uncommitted Hash table changes */
 #define DBFLAG_PreferBuiltin  0x0002  /* Preference to built-in funcs */
 #define DBFLAG_Vacuum         0x0004  /* Currently in a VACUUM */
+#define DBFLAG_SchemaKnownOk  0x0008  /* Schema is known to be valid */
 
 /*
 ** Bits of the sqlite3.dbOptFlags field that are used by the