Performance improvement in the sqlite3_initialize() interface.

FossilOrigin-Name: 4ad701b085ce1b9ada41441f560e55580f0dd33e8145857afce6c665aa974ad0

manifest

@@ -1,5 +1,5 @@
-C Fix\sboundary\scases\sof\srowid\slookup\susing\svery\slarge\sfloating\spoint\svalues\s-\nvalues\snear\sthe\sminimum\sand\smaximum\s64-bit\ssigned\sinteger.\n[forum:/info/2026-07-19T07:31:46Z|Forum\s2026-07-19T07:31:46Z].
-D 2026-07-19T19:49:24.674
+C Performance\simprovement\sin\sthe\ssqlite3_initialize()\sinterface.
+D 2026-07-20T11:50:37.472
 F .fossil-settings/binary-glob 61195414528fb3ea9693577e1980230d78a1f8b0a54c78cf1b9b24d0a409ed6a x
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
@@ -706,7 +706,7 @@ F src/insert.c e6e9b574b4863649e2c433f2260f226183e697df1ab73fcb8da9a85d5abcd390
 F src/json.c e4af4d799e4e7630c633b3b356d65e92d1781e42343ab77b8ef747c932762012
 F src/legacy.c d7874bc885906868cd51e6c2156698f2754f02d9eee1bae2d687323c3ca8e5aa
 F src/loadext.c 5cd4cd7ec6e1a46416806899086363fbf95eecd3bfb9a388b436c9a77243c902
-F src/main.c b0a4b497d0bf4414bdcd5dda81c49851fca7b6781e9e485ac4c360b291f6dbb8
+F src/main.c 2af1793f14ae547168e11682720aefc360d3fec75bc1dbabd9565ca09b02c8ab
 F src/malloc.c 422f7e0498e1c9ef967f06283b6f2c0b16db6b905d8e06f6dbc8baaa3e4e6c5a
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c 3bb59158c38e05f6270e761a9f435bf19827a264c13d1631c58b84bdc96d73b2
@@ -2215,8 +2215,8 @@ F tool/warnings-clang.sh bbf6a1e685e534c92ec2bfba5b1745f34fb6f0bc2a362850723a9ee
 F tool/warnings.sh a554d13f6e5cf3760f041b87939e3d616ec6961859c3245e8ef701d1eafc2ca2
 F tool/win/sqlite.vsix deb315d026cc8400325c5863eef847784a219a2f
 F tool/winmain.c 00c8fb88e365c9017db14c73d3c78af62194d9644feaf60e220ab0f411f3604c
-P 436cf63e941b3db936a01d4584c9e3cc9675ce9ef4b6689530218c27252c170d
-R d5f2585f74441642eac52f7b29db0d93
+P 987ba5a3dc5f2a2294b77ef3ec1ea06682f0530a7268777c6b64985dd0e90d40
+R 225576c20d8aa54d888d7e314b9b6b32
 U drh
-Z 7d9a924e268268fab71b80580c8683dc
+Z dff319d19633fb41fe302187d5c63413
 # Remove this line to create a well-formed Fossil manifest.

manifest.uuid

@@ -1 +1 @@
-987ba5a3dc5f2a2294b77ef3ec1ea06682f0530a7268777c6b64985dd0e90d40
+4ad701b085ce1b9ada41441f560e55580f0dd33e8145857afce6c665aa974ad0

src/main.c

@@ -159,17 +159,29 @@ char *sqlite3_data_directory = 0;
 /*
 ** Initialize SQLite. 
 **
-** This routine must be called to initialize the memory allocation,
-** VFS, and mutex subsystems prior to doing any serious work with
-** SQLite.  But as long as you do not compile with SQLITE_OMIT_AUTOINIT
+** The sqlite3_initialize() routine must be called to initialize the
+** memory allocation, VFS, and mutex subsystems prior to doing any
+** serious work.  As long as you do not compile with SQLITE_OMIT_AUTOINIT
 ** this routine will be called automatically by key routines such as
 ** sqlite3_open(). 
 **
 ** This routine is a no-op except on its very first call for the process,
-** or for the first call after a call to sqlite3_shutdown.
+** or for the first call after a call to sqlite3_shutdown.  Most calls
+** to sqlite3_initialize() are, in fact, no-ops.  For that reason, the
+** routine is broken into two pieces:
 **
-** The first thread to call this routine runs the initialization to
-** completion.  If subsequent threads call this routine before the first
+**     sqlite3Initialize()     Does the actual work of initialization
+**
+**     sqlite3_initialize()    Checks to see if initialization is needed
+**                             and invokes sqlite3Initialize() if it is.
+**
+** The sqlite3_initialize() interface is called frequently, but
+** sqlite3Initialize() runs rarely.  The function is broken up this way
+** to avoid wasting CPU cycles with unnecessary stack setup for local
+** variables in cases where it is not needed.
+**
+** The first thread to call sqlite3_initialize() runs the initialization to
+** completion. If subsequent threads call sqlite3_initialize() before the first
 ** thread has finished the initialization process, then the subsequent
 ** threads must block until the first thread finishes with the initialization.
 **
@@ -177,44 +189,29 @@ char *sqlite3_data_directory = 0;
 ** calls to this routine should not block, of course.  Otherwise the
 ** initialization process would never complete.
 **
-** Let X be the first thread to enter this routine.  Let Y be some other
-** thread.  Then while the initial invocation of this routine by X is
-** incomplete, it is required that:
+** Let X be the first thread to enter sqlite3_initialize().  Let Y be some
+** other thread.  While the initial invocation of sqlite3_initialize() by X
+** is incomplete, it is required that:
 **
-**    *  Calls to this routine from Y must block until the outer-most
+**    *  Calls to sqlite3_initialize() from Y must block until the outer-most
 **       call by X completes.
 **
-**    *  Recursive calls to this routine from thread X return immediately
-**       without blocking.
+**    *  Recursive calls to sqlite3_initialize() from thread X return
+**       immediately without blocking.
 */
-int sqlite3_initialize(void){
-  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; )      /* The main static mutex */
-  int rc;                                      /* Result code */
+static SQLITE_NOINLINE int sqlite3Initialize(void){
+  MUTEX_LOGIC( sqlite3_mutex *pMainMtx; )   /* The main static mutex */
+  int rc;                                   /* Result code */
 #ifdef SQLITE_EXTRA_INIT
-  int bRunExtraInit = 0;                       /* Extra initialization needed */
-#endif
-
-#ifdef SQLITE_OMIT_WSD
-  rc = sqlite3_wsd_init(4096, 24);
-  if( rc!=SQLITE_OK ){
-    return rc;
-  }
+  int bRunExtraInit = 0;                    /* Extra initialization needed */
 #endif
 
   /* If the following assert() fails on some obscure processor/compiler
-  ** combination, the work-around is to set the correct pointer
-  ** size at compile-time using -DSQLITE_PTRSIZE=n compile-time option */
-  assert( SQLITE_PTRSIZE==sizeof(char*) );
-
-  /* If SQLite is already completely initialized, then this call
-  ** to sqlite3_initialize() should be a no-op.  But the initialization
-  ** must be complete.  So isInit must not be set until the very end
-  ** of this routine.
+  ** combination to warn that SQLite has been mis-compiled.  If you hit
+  ** this assert(), that means you need to recompile with the
+  ** -DSQLITE_PTRSIZE=n compile-time option to set the correct pointer size.
   */
-  if( sqlite3GlobalConfig.isInit ){
-    sqlite3MemoryBarrier();
-    return SQLITE_OK;
-  }
+  assert( SQLITE_PTRSIZE==sizeof(char*) );
 
   /* Make sure the mutex subsystem is initialized.  If unable to
   ** initialize the mutex subsystem, return early with the error.
@@ -360,6 +357,26 @@ int sqlite3_initialize(void){
 #endif
   return rc;
 }
+SQLITE_API int sqlite3_initialize(void){
+  /* If this build does not support writable static data (WSD) natively
+  ** then we have to invoke the (application-supplied) WSD initialization
+  ** routine before doing anything else. */
+#ifdef SQLITE_OMIT_WSD
+  rc = sqlite3_wsd_init(4096, 24);
+  if( rc!=SQLITE_OK ){
+    return rc;
+  }
+#endif
+
+  if( sqlite3GlobalConfig.isInit ){
+    /* SQLite has already been initialized.  Fast early-out. */
+    sqlite3MemoryBarrier();
+    return SQLITE_OK;
+  }else{
+    /* Invoke sqlite3Initialize() to do the actual work. */
+    return sqlite3Initialize();
+  }
+}
 
 /*
 ** Undo the effects of sqlite3_initialize().  Must not be called while