SQLite

** modes (delete, truncate, persist, off and memory), this is a simple
** operation. No IO is required.
**
** If changing into or out of WAL mode the procedure is more complicated.
**
** Write a string containing the final journal-mode to register P2.
*/
case OP_JournalMode: {    /* out2-prerelease */
  Btree *pBt;                     /* Btree to change journal mode of */
  Pager *pPager;                  /* Pager associated with pBt */
  int eNew;                       /* New journal mode */
  int eOld;                       /* The old journal mode */
  const sqlite3_vfs *pVfs;        /* The VFS of pPager */
  const char *zFilename;          /* Name of database file for pPager */

  eNew = pOp->p3;
  assert( eNew==PAGER_JOURNALMODE_DELETE 
       || eNew==PAGER_JOURNALMODE_TRUNCATE 
       || eNew==PAGER_JOURNALMODE_PERSIST 
       || eNew==PAGER_JOURNALMODE_OFF
       || eNew==PAGER_JOURNALMODE_MEMORY
       || eNew==PAGER_JOURNALMODE_WAL
       || eNew==PAGER_JOURNALMODE_QUERY
  );
  assert( pOp->p1>=0 && pOp->p1<db->nDb );
  assert( (p->btreeMask & (1<<pOp->p1))!=0 );

  pBt = db->aDb[pOp->p1].pBt;
  pPager = sqlite3BtreePager(pBt);
  zFilename = sqlite3PagerFilename(pPager);
  pVfs = sqlite3PagerVfs(pPager);


  /* Do not allow a transition to journal_mode=WAL for a database
  ** in temporary storage or if the VFS does not support xShmOpen.
  */
  if( eNew==PAGER_JOURNALMODE_WAL
   && (zFilename[0]==0                               /* Temp file */
         || pVfs->iVersion<2 || pVfs->xShmOpen==0)   /* No xShmOpen support */
  ){
    eNew = PAGER_JOURNALMODE_QUERY;
  }

  if( eNew!=PAGER_JOURNALMODE_QUERY ){
    eOld = sqlite3PagerJournalMode(pPager, PAGER_JOURNALMODE_QUERY);
    if( (eNew!=eOld)
     && (eOld==PAGER_JOURNALMODE_WAL || eNew==PAGER_JOURNALMODE_WAL)
    ){
      if( !db->autoCommit || db->activeVdbeCnt>1 ){
        rc = SQLITE_ERROR;
        sqlite3SetString(&p->zErrMsg, db, 
            "cannot change %s wal mode from within a transaction",

#   walmode-5.2.*: Try to set journal_mode=WAL on [sqlite3 db ""] database.
#   walmode-5.3.*: Try to set temp.journal_mode=WAL.
#
do_test walmode-5.1.1 {
  sqlite3 db :memory:
  execsql { PRAGMA main.journal_mode }
} {memory}
breakpoint
do_test walmode-5.1.2 {
  execsql { PRAGMA main.journal_mode = wal }
} {memory}
do_test walmode-5.1.3 {
  execsql {
    BEGIN;
      CREATE TABLE t1(a, b);

  execsql { 
    INSERT INTO t1 VALUES(3, 4);
    SELECT * FROM t1;
    PRAGMA main.journal_mode;
  }
} {1 2 3 4 delete}

if {$TEMP_STORE>=2} {
  set tempJrnlMode memory
} else {
  set tempJrnlMode
}
do_test walmode-5.3.1 {
  sqlite3 db test.db
  execsql { PRAGMA temp.journal_mode }
} $tempJrnlMode
do_test walmode-5.3.2 {
  execsql { PRAGMA temp.journal_mode = wal }
} $tempJrnlMode
do_test walmode-5.3.3 {
  execsql {
    BEGIN;
      CREATE TEMP TABLE t1(a, b);
      INSERT INTO t1 VALUES(1, 2);
    COMMIT;
    SELECT * FROM t1;
    PRAGMA temp.journal_mode;
  }
} [list 1 2 $tempJrnlMode]
do_test walmode-5.3.4 {
  execsql { PRAGMA temp.journal_mode = wal }
} $tempJrnlMode
do_test walmode-5.3.5 {
  execsql { 
    INSERT INTO t1 VALUES(3, 4);
    SELECT * FROM t1;
    PRAGMA temp.journal_mode;
  }
} [list 1 2 3 4 $tempJrnlMode]

finish_test