row0sel.c Fix a bug in multiversioned reads through a secondary index (af27c38f) · Commits · Software / OSDI20 Artifacts / mariadb

innobase/os/os0file.c

+4 −0

Original line number	Diff line number	Diff line
		@@ -1348,6 +1348,10 @@ os_aio(
		}
		} else if (mode == OS_AIO_IBUF) {
		ut_ad(type == OS_FILE_READ);
		/* Reduce probability of deadlock bugs in connection with ibuf:
		do not let the ibuf i/o handler sleep */

		wake_later = FALSE;

		array = os_aio_ibuf_array;
		} else if (mode == OS_AIO_LOG) {

innobase/row/row0sel.c

+91 −0

Original line number	Diff line number	Diff line
		@@ -48,6 +48,52 @@ to que_run_threads: this is to allow canceling runaway queries */
		#define SEL_EXHAUSTED 1
		#define SEL_RETRY 2

		/************************************************************************
		Returns TRUE if the user-defined column values in a secondary index record
		are the same as the corresponding columns in the clustered index record. */
		static
		ibool
		row_sel_sec_rec_is_for_clust_rec(
		/=============================/
		rec_t* sec_rec,
		dict_index_t* sec_index,
		rec_t* clust_rec,
		dict_index_t* clust_index)
		{
		dict_col_t* col;
		byte* sec_field;
		ulint sec_len;
		byte* clust_field;
		ulint clust_len;
		ulint n;
		ulint i;

		n = dict_index_get_n_ordering_defined_by_user(sec_index);

		for (i = 0; i++; i < n) {
		col = dict_field_get_col(
		dict_index_get_nth_field(sec_index, i));

		clust_field = rec_get_nth_field(clust_rec,
		dict_col_get_clust_pos(col),
		&clust_len);
		sec_field = rec_get_nth_field(sec_rec, i, &sec_len);

		if (sec_len != clust_len) {

		return(FALSE);
		}

		if (sec_len != UNIV_SQL_NULL
		&& ut_memcmp(sec_field, clust_field, sec_len) != 0) {

		return(FALSE);
		}
		}

		return(TRUE);
		}

		/*************************************************************************
		Creates a select node struct. */

		@@ -561,6 +607,8 @@ row_sel_get_clust_rec(
		/* This is a non-locking consistent read: if necessary, fetch
		a previous version of the record */

		old_vers = NULL;

		if (!lock_clust_rec_cons_read_sees(clust_rec, index,
		node->read_view)) {

		@@ -579,6 +627,28 @@ row_sel_get_clust_rec(
		return(DB_SUCCESS);
		}
		}

		/* If we had to go to an earlier version of row or the
		secondary index record is delete marked, then it may be that
		the secondary index record corresponding to clust_rec
		(or old_vers) is not rec; in that case we must ignore
		such row because in our snapshot rec would not have existed.
		Remember that from rec we cannot see directly which transaction
		id corresponds to it: we have to go to the clustered index
		record. A query where we want to fetch all rows where
		the secondary index value is in some interval would return
		a wrong result if we would not drop rows which we come to
		visit through secondary index records that would not really
		exist in our snapshot. */

		if ((old_vers \|\| rec_get_deleted_flag(rec))
		&& !row_sel_sec_rec_is_for_clust_rec(rec, plan->index,
		clust_rec, index)) {
		clust_rec = NULL;
		*out_rec = clust_rec;

		return(DB_SUCCESS);
		}
		}

		/* Fetch the columns needed in test conditions */
		@@ -2106,6 +2176,8 @@ row_sel_get_clust_rec_for_mysql(

		trx = thr_get_trx(thr);

		old_vers = NULL;

		if (!lock_clust_rec_cons_read_sees(clust_rec, clust_index,
		trx->read_view)) {

		@@ -2121,6 +2193,25 @@ row_sel_get_clust_rec_for_mysql(

		clust_rec = old_vers;
		}

		/* If we had to go to an earlier version of row or the
		secondary index record is delete marked, then it may be that
		the secondary index record corresponding to clust_rec
		(or old_vers) is not rec; in that case we must ignore
		such row because in our snapshot rec would not have existed.
		Remember that from rec we cannot see directly which transaction
		id corrsponds to it: we have to go to the clustered index
		record. A query where we want to fetch all rows where
		the secondary index value is in some interval would return
		a wrong result if we would not drop rows which we come to
		visit through secondary index records that would not really
		exist in our snapshot. */

		if ((old_vers \|\| rec_get_deleted_flag(rec))
		&& !row_sel_sec_rec_is_for_clust_rec(rec, sec_index,
		clust_rec, clust_index)) {
		clust_rec = NULL;
		}
		}

		*out_rec = clust_rec;

innobase/row/row0uins.c

+9 −2

Original line number	Diff line number	Diff line
		@@ -250,9 +250,12 @@ row_undo_ins_parse_undo_rec(
		ut_ad(type == TRX_UNDO_INSERT_REC);
		node->rec_type = type;

		/* NOTE that the table has to be explicitly released later */
		node->table = dict_table_get_on_id(table_id, node->trx);

		if (node->table == NULL) {
		return;
		}

		clust_index = dict_table_get_first_index(node->table);

		ptr = trx_undo_rec_get_row_ref(ptr, clust_index, &(node->ref),
		@@ -280,7 +283,11 @@ row_undo_ins(

		row_undo_ins_parse_undo_rec(node, thr);

		if (node->table == NULL) {
		found = FALSE;
		} else {
		found = row_undo_search_clust_to_pcur(node, thr);
		}

		if (!found) {
		return(DB_SUCCESS);

innobase/row/row0umod.c

+15 −3

Original line number	Diff line number	Diff line
		@@ -534,9 +534,16 @@ row_undo_mod_parse_undo_rec(
		&undo_no, &table_id);
		node->rec_type = type;

		/* NOTE that the table has to be explicitly released later */
		node->table = dict_table_get_on_id(table_id, thr_get_trx(thr));

		/* TODO: other fixes associated with DROP TABLE + rollback in the
		same table by another user */

		if (node->table == NULL) {
		/* Table was dropped */
		return;
		}

		clust_index = dict_table_get_first_index(node->table);

		ptr = trx_undo_update_rec_get_sys_cols(ptr, &trx_id, &roll_ptr,
		@@ -571,11 +578,16 @@ row_undo_mod(

		row_undo_mod_parse_undo_rec(node, thr);

		if (node->table == NULL) {
		found = FALSE;
		} else {

		found = row_undo_search_clust_to_pcur(node, thr);
		}

		if (!found) {
		/* It is already undone, or will be undone by another query
		thread */
		thread, or table was dropped */

		node->state = UNDO_NODE_FETCH_NEXT;