Commit 16bce93c authored by John Esmet's avatar John Esmet Committed by Yoni Fogel
Browse files

[t:4542] comment how zombies work with dbremove and the rollback code 


git-svn-id: file:///svn/toku/tokudb@41718 c7de825b-a66e-492c-adef-691d508d4ae1
parent 6d7665e8

newbrt/roll.c

+10 −1
Original line number Diff line number Diff line
@@ -44,7 +44,10 @@ toku_commit_fdelete (u_int8_t file_was_open, 
            r = 0;

            goto done;

        }

        assert(r == 0);  // must still be open  (toku_brt_remove_on_commit() incremented refcount)

        // file must be open now if it was open when the fdelete was logged,

        // because the txn that created it opened it and noted it.

        // XXX this does not look true "must still be open  (toku_brt_remove_on_commit() incremented refcount)"

        assert(r == 0); 

        {

            (void)toku_cachefile_get_and_pin_fd(cf);

            assert(!toku_cachefile_is_dev_null_unlocked(cf));
@@ -111,6 +114,9 @@ toku_rollback_fcreate (FILENUM filenum, 
        r = 0;

        goto done;

    }

    // file must be open, because the txn that created it opened it and

    // noted it, so another client trying to close it would force it

    // to become a zombie.

    assert(r == 0);

    {

        (void)toku_cachefile_get_and_pin_fd(cf);
@@ -571,6 +577,9 @@ toku_rollback_change_fdescriptor(FILENUM filenum, 
        r = 0;

        goto done;

    }

    // file must be open, because the txn that created it opened it and

    // noted it, so another client trying to close it would force it

    // to become a zombie.

    assert(r==0);



    fd = toku_cachefile_get_and_pin_fd(cf);

src/ydb.c

+9 −0
Original line number Diff line number Diff line
@@ -2759,12 +2759,21 @@ toku_env_dbremove(DB_ENV * env, DB_TXN *txn, const char *fname, const char *dbna 
	r = toku_db_del(env->i->directory, child, &dname_dbt, DB_DELETE_ANY, TRUE);

	if (r == 0) {

            if (using_txns) {

                // this writes an fdelete to the transaction's rollback log.

                // it is removed if the child txn aborts after any error case below

                r = toku_brt_remove_on_commit(db_txn_struct_i(child)->tokutxn, &iname_dbt);

		assert_zero(r);

                //Now that we have a writelock on dname, verify that there are still no handles open. (to prevent race conditions)

                if (r==0 && env_is_db_with_dname_open(env, dname))

                    r = toku_ydb_do_error(env, EINVAL, "Cannot remove dictionary with an open handle.\n");

                if (r==0) {

                    // we know a live db handle does not exist.

                    //

                    // if there exists a zombie, make sure that it is due to

                    // checkpoint by trying to get a table lock. we can't

                    // remove a db that live txns reference, but it's okay

                    // to deal with the fact that its pinned for checkpoint

                    // further down the stack.

                    DB* zombie = env_get_zombie_db_with_dname(env, dname);

                    if (zombie)

                        r = toku_db_pre_acquire_table_lock(zombie, child, TRUE);