libsql-sqlite3: Optimize pager codec check more

Checking if we have a custom codec at pager open time is still plenty
slow. Change the check to happen at database open time instead.

Author: penberg

libsql-ffi/bundled/SQLite3MultipleCiphers/src/codecext.c

@@ -8,10 +8,10 @@
 */
 
 /*
-** Forward declaration for pager codec cache update function.
-** This should be called after encryption is added, removed, or changed.
+** Forward declaration for db codec check function.
+** Used to update cached codec status after encryption changes.
 */
-void libsql_pager_update_codec_cache(struct Pager *pPager);
+int libsql_db_has_codec(sqlite3_vfs* pVfs, const char* zFilename);
 
 /*
 ** "Special" version of function sqlite3BtreeSetPageSize
@@ -591,8 +591,8 @@ sqlite3_rekey_v2(sqlite3* db, const char* zDbName, const void* zKey, int nKey)
     {
       sqlite3mcSetIsEncrypted(codec, 0);
     }
-    /* Update the pager's cached codec status after changing encryption */
-    libsql_pager_update_codec_cache(pPager);
+    /* Update both pager and database cached codec status after changing encryption */
+    db->aDb[dbIndex].hasCodec = pPager->hasCodec = libsql_db_has_codec(pPager->pVfs, pPager->zFilename);
   }
   else
   {

libsql-ffi/bundled/SQLite3MultipleCiphers/src/sqlite3.c

@@ -16436,7 +16436,8 @@ SQLITE_PRIVATE int sqlite3PagerOpen(
   int,
   int,
   int,
-  void(*)(DbPage*)
+  void(*)(DbPage*),
+  int                    /* hasCodec from connection-level cache */
 );
 SQLITE_PRIVATE int sqlite3PagerClose(Pager *pPager, sqlite3*);
 SQLITE_PRIVATE int sqlite3PagerReadFileheader(Pager*, int, unsigned char*);
@@ -16625,7 +16626,8 @@ SQLITE_PRIVATE int sqlite3BtreeOpen(
   sqlite3 *db,             /* Associated database connection */
   Btree **ppBtree,         /* Return open Btree* here */
   int flags,               /* Flags */
-  int vfsFlags             /* Flags passed through to VFS open */
+  int vfsFlags,            /* Flags passed through to VFS open */
+  int hasCodec             /* True if this database has encryption codec */
 );
 
 /* The flags parameter to sqlite3BtreeOpen can be the bitwise or of the
@@ -17993,6 +17995,7 @@ struct Db {
   Btree *pBt;          /* The B*Tree structure for this database file */
   u8 safety_level;     /* How aggressive at syncing data to disk */
   u8 bSyncSet;         /* True if "PRAGMA synchronous=N" has been run */
+  u8 hasCodec;         /* True if this database has encryption codec */
   Schema *pSchema;     /* Pointer to database schema (possibly shared) */
 };
 
@@ -58232,27 +58235,18 @@ struct Pager {
 /* libSQL extension: pager codec */
 
 #ifdef LIBSQL_CUSTOM_PAGER_CODEC
-int libsql_pager_has_codec_impl(struct Pager *_p);
 int libsql_pager_codec_impl(libsql_pghdr *hdr, void **ret);
+int libsql_db_has_codec(sqlite3_vfs* pVfs, const char* zFilename);
 #endif
 
 int libsql_pager_has_codec(struct Pager *_p) {
 #ifdef LIBSQL_CUSTOM_PAGER_CODEC
-  return libsql_pager_has_codec_impl(_p);
+  return libsql_db_has_codec(_p->pVfs, _p->zFilename);
 #else
   return 0;
 #endif
 }
 
-/*
-** Update the cached codec status.
-** This should be called after encryption is added, removed, or changed
-** via sqlite3_rekey_v2() to ensure the cached hasCodec value is correct.
-*/
-void libsql_pager_update_codec_cache(struct Pager *pPager) {
-  pPager->hasCodec = libsql_pager_has_codec(pPager);
-}
-
 int libsql_pager_codec(libsql_pghdr *hdr, void **ret) {
   if (!ret) {
 	return SQLITE_MISUSE_BKPT;
@@ -62295,7 +62289,8 @@ SQLITE_PRIVATE int sqlite3PagerOpen(
   int nExtra,              /* Extra bytes append to each in-memory page */
   int flags,               /* flags controlling this file */
   int vfsFlags,            /* flags passed through to sqlite3_vfs.xOpen() */
-  void (*xReinit)(DbPage*) /* Function to reinitialize pages */
+  void (*xReinit)(DbPage*),/* Function to reinitialize pages */
+  int dbHasCodec           /* hasCodec from connection-level cache */
 ){
   u8 *pPtr;
   Pager *pPager = 0;       /* Pager object to allocate and return */
@@ -62635,8 +62630,9 @@ SQLITE_PRIVATE int sqlite3PagerOpen(
   /* pPager->xBusyHandler = 0; */
   /* pPager->pBusyHandlerArg = 0; */
   pPager->xReiniter = xReinit;
-  /* Cache the codec check result to avoid expensive VFS stack traversal on every page read */
-  pPager->hasCodec = libsql_pager_has_codec(pPager);
+  /* Use cached codec status from connection level to avoid expensive VFS stack traversal
+  ** and file lookup on every pager initialization */
+  pPager->hasCodec = dbHasCodec;
   setGetterMethod(pPager);
   /* memset(pPager->aHash, 0, sizeof(pPager->aHash)); */
   /* pPager->szMmap = SQLITE_DEFAULT_MMAP_SIZE // will be set by btree.c */
@@ -73757,7 +73753,8 @@ SQLITE_PRIVATE int sqlite3BtreeOpen(
   sqlite3 *db,             /* Associated database handle */
   Btree **ppBtree,         /* Pointer to new Btree object written here */
   int flags,               /* Options */
-  int vfsFlags             /* Flags passed through to sqlite3_vfs.xOpen() */
+  int vfsFlags,            /* Flags passed through to sqlite3_vfs.xOpen() */
+  int hasCodec             /* True if this database has encryption codec */
 ){
   BtShared *pBt = 0;             /* Shared part of btree structure */
   Btree *p;                      /* Handle to return */
@@ -73902,7 +73899,7 @@ SQLITE_PRIVATE int sqlite3BtreeOpen(
       goto btree_open_out;
     }
     rc = sqlite3PagerOpen(pVfs, db->wal_manager ,&pBt->pPager, zFilename,
-                          sizeof(MemPage), flags, vfsFlags, pageReinit);
+                          sizeof(MemPage), flags, vfsFlags, pageReinit, hasCodec);
     if( rc==SQLITE_OK ){
       sqlite3PagerSetMmapLimit(pBt->pPager, db->szMmap);
       rc = sqlite3PagerReadFileheader(pBt->pPager,sizeof(zDbHeader),zDbHeader);
@@ -98769,7 +98766,8 @@ case OP_OpenEphemeral: {     /* ncycle */
     pCx->isEphemeral = 1;
     rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pCx->ub.pBtx,
                           BTREE_OMIT_JOURNAL | BTREE_SINGLE | pOp->p5,
-                          vfsFlags);
+                          vfsFlags,
+                          0);  /* Ephemeral tables are never encrypted */
     if( rc==SQLITE_OK ){
       rc = sqlite3BtreeBeginTrans(pCx->ub.pBtx, 1, 0);
       if( rc==SQLITE_OK ){
@@ -121888,6 +121886,10 @@ int libsql_handle_extra_attach_params(sqlite3* db, const char* zName, const char
 SQLITE_PRIVATE int sqlite3mcHandleAttachKey(sqlite3*, const char*, const char*, sqlite3_value*, char**);
 #endif
 
+#ifdef LIBSQL_CUSTOM_PAGER_CODEC
+int libsql_db_has_codec(sqlite3_vfs* pVfs, const char* zFilename);
+#endif
+
 /*
 ** An SQL user-function registered to do the work of an ATTACH statement. The
 ** three arguments to the function come directly from an attach statement:
@@ -121940,7 +121942,8 @@ static void attachFunc(
     Btree *pNewBt = 0;
     pVfs = sqlite3_vfs_find("memdb");
     if( pVfs==0 ) return;
-    rc = sqlite3BtreeOpen(pVfs, "x\0", db, &pNewBt, 0, SQLITE_OPEN_MAIN_DB);
+    rc = sqlite3BtreeOpen(pVfs, "x\0", db, &pNewBt, 0, SQLITE_OPEN_MAIN_DB,
+                          0);  /* Memdb databases are never encrypted */
     if( rc==SQLITE_OK ){
       Schema *pNewSchema = sqlite3SchemaGet(db, pNewBt);
       if( pNewSchema ){
@@ -122009,7 +122012,13 @@ static void attachFunc(
     }
     assert( pVfs );
     flags |= SQLITE_OPEN_MAIN_DB;
-    rc = sqlite3BtreeOpen(pVfs, zPath, db, &pNew->pBt, 0, flags);
+    /* Check encryption status for this database file */
+#ifdef LIBSQL_CUSTOM_PAGER_CODEC
+    pNew->hasCodec = libsql_db_has_codec(pVfs, zPath);
+#else
+    pNew->hasCodec = 0;
+#endif
+    rc = sqlite3BtreeOpen(pVfs, zPath, db, &pNew->pBt, 0, flags, pNew->hasCodec);
     db->nDb++;
     pNew->zDbSName = sqlite3DbStrDup(db, zName);
   }
@@ -128047,7 +128056,8 @@ SQLITE_PRIVATE int sqlite3OpenTempDatabase(Parse *pParse){
           SQLITE_OPEN_DELETEONCLOSE |
           SQLITE_OPEN_TEMP_DB;
 
-    rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pBt, 0, flags);
+    db->aDb[1].hasCodec = 0;  /* Temp databases are never encrypted */
+    rc = sqlite3BtreeOpen(db->pVfs, 0, db, &pBt, 0, flags, db->aDb[1].hasCodec);
     if( rc!=SQLITE_OK ){
       sqlite3ErrorMsg(pParse, "unable to open a temporary database "
         "file for storing temporary tables");
@@ -184304,6 +184314,10 @@ static const char *uriParameter(const char *zFilename, const char *zParam){
 int libsql_handle_extra_uri_params(sqlite3 *db, const char *zOpen);
 #endif
 
+#ifdef LIBSQL_CUSTOM_PAGER_CODEC
+int libsql_db_has_codec(sqlite3_vfs* pVfs, const char* zFilename);
+#endif
+
 /*
 ** This routine does the work of opening a database on behalf of
 ** sqlite3_open() and sqlite3_open16(). The database filename "zFilename"
@@ -184559,9 +184573,17 @@ static int openDatabase(
   }
 #endif
 
+  /* Cache encryption status at database open time to avoid expensive
+  ** VFS stack traversal and file lookup on every pager initialization */
+#ifdef LIBSQL_CUSTOM_PAGER_CODEC
+  db->aDb[0].hasCodec = libsql_db_has_codec(db->pVfs, zOpen);
+#else
+  db->aDb[0].hasCodec = 0;
+#endif
+
   /* Open the backend database driver */
   rc = sqlite3BtreeOpen(db->pVfs, zOpen, db, &db->aDb[0].pBt, 0,
-                        flags | SQLITE_OPEN_MAIN_DB);
+                        flags | SQLITE_OPEN_MAIN_DB, db->aDb[0].hasCodec);
   if( rc!=SQLITE_OK ){
     if( rc==SQLITE_IOERR_NOMEM ){
       rc = SQLITE_NOMEM_BKPT;

libsql-ffi/bundled/SQLite3MultipleCiphers/src/sqlite3mc_vfs.c

@@ -1347,13 +1347,18 @@ sqlite3mcCheckVfs(const char* zVfs)
   return rc;
 }
 
-int libsql_pager_has_codec_impl(struct Pager* pPager)
+/*
+** Check if a database file is encrypted at connection open time.
+** This checks both the VFS stack and the specific file encryption status.
+** The result is cached at the connection level to avoid expensive checks
+** on every pager initialization.
+*/
+int libsql_db_has_codec(sqlite3_vfs* pVfs, const char* zFilename)
 {
   int hasCodec = 0;
   sqlite3mc_vfs* pVfsMC = NULL;
-  sqlite3_vfs* pVfs = pPager->pVfs;
 
-  /* Check whether the VFS stack of the pager contains a Multiple Ciphers VFS */
+  /* Check whether the VFS stack contains a Multiple Ciphers VFS */
   for (; pVfs; pVfs = pVfs->pNext)
   {
     if (pVfs && pVfs->xOpen == mcVfsOpen)
@@ -1367,7 +1372,7 @@ int libsql_pager_has_codec_impl(struct Pager* pPager)
   /* Check whether codec is enabled for associated database file */
   if (pVfsMC)
   {
-    sqlite3mc_file* mcFile = mcFindDbMainFileName(pVfsMC, pPager->zFilename);
+    sqlite3mc_file* mcFile = mcFindDbMainFileName(pVfsMC, zFilename);
     if (mcFile)
     {
       Codec* codec = mcFile->codec;