- Reverted 2c4844c9e76427525e8c39a2d72686085efe89c3. The scenario10.5-MDEV-16678

become useless after purge thread uses MDL

6 files changed, 7 insertions, 133 deletions

diff --git a/mysql-test/suite/innodb/r/instant_alter_purge.result b/mysql-test/suite/innodb/r/instant_alter_purge.result
index a3643610f04..1179ff62ecc 100644
--- a/mysql-test/suite/innodb/r/instant_alter_purge.result
+++ b/mysql-test/suite/innodb/r/instant_alter_purge.result
@@ -21,26 +21,4 @@ ALTER TABLE t1 DROP extra;
 disconnect prevent_purge;
 InnoDB		0 transactions not purged
 DROP TABLE t1;
-#
-# MDEV-17813 Crash in instant ALTER TABLE due to purge
-# concurrently emptying table
-#
-CREATE TABLE t1 (f2 INT) ENGINE=InnoDB;
-INSERT INTO t1 SET f2=1;
-ALTER TABLE t1 ADD COLUMN f1 INT;
-connect  purge_control,localhost,root;
-START TRANSACTION WITH CONSISTENT SNAPSHOT;
-connection default;
-DELETE FROM t1;
-SET DEBUG_SYNC='innodb_commit_inplace_alter_table_enter SIGNAL go WAIT_FOR do';
-ALTER TABLE t1 ADD COLUMN f3 INT;
-connection purge_control;
-SET DEBUG_SYNC='now WAIT_FOR go';
-COMMIT;
-InnoDB		0 transactions not purged
-SET DEBUG_SYNC='now SIGNAL do';
-disconnect purge_control;
-connection default;
-SET DEBUG_SYNC=RESET;
-DROP TABLE t1;
 SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
diff --git a/mysql-test/suite/innodb/r/purge_thread_shutdown.result b/mysql-test/suite/innodb/r/purge_thread_shutdown.result
index a87cba89917..f1b0cb07ce8 100644
--- a/mysql-test/suite/innodb/r/purge_thread_shutdown.result
+++ b/mysql-test/suite/innodb/r/purge_thread_shutdown.result
@@ -6,6 +6,7 @@ select user,state from information_schema.processlist order by 2;
 user	state
 root	
 root	Filling schema table
+system user	InnoDB fts optimize thread
 system user	InnoDB purge coordinator
 system user	InnoDB purge worker
 system user	InnoDB purge worker
@@ -19,6 +20,7 @@ disconnect con1;
 select user,state from information_schema.processlist order by 2;
 user	state
 root	Filling schema table
+system user	InnoDB fts optimize thread
 system user	InnoDB purge coordinator
 system user	InnoDB purge worker
 system user	InnoDB purge worker
diff --git a/mysql-test/suite/innodb/t/instant_alter_purge.test b/mysql-test/suite/innodb/t/instant_alter_purge.test
index 152d200d977..9ccf3347d7b 100644
--- a/mysql-test/suite/innodb/t/instant_alter_purge.test
+++ b/mysql-test/suite/innodb/t/instant_alter_purge.test
@@ -34,42 +34,4 @@ disconnect prevent_purge;
 let $wait_all_purged= 0;
 --source include/wait_all_purged.inc
 DROP TABLE t1;
-
---echo #
---echo # MDEV-17813 Crash in instant ALTER TABLE due to purge
---echo # concurrently emptying table
---echo #
-CREATE TABLE t1 (f2 INT) ENGINE=InnoDB;
-INSERT INTO t1 SET f2=1;
-ALTER TABLE t1 ADD COLUMN f1 INT;
-
-connect (purge_control,localhost,root);
-START TRANSACTION WITH CONSISTENT SNAPSHOT;
-
-connection default;
-DELETE FROM t1;
-
-if ($have_debug) {
-SET DEBUG_SYNC='innodb_commit_inplace_alter_table_enter SIGNAL go WAIT_FOR do';
-}
-send ALTER TABLE t1 ADD COLUMN f3 INT;
-
-connection purge_control;
-if ($have_debug) {
-SET DEBUG_SYNC='now WAIT_FOR go';
-}
-COMMIT;
---source include/wait_all_purged.inc
-if ($have_debug) {
-SET DEBUG_SYNC='now SIGNAL do';
-}
-disconnect purge_control;
-
-connection default;
-reap;
-if ($have_debug) {
-SET DEBUG_SYNC=RESET;
-}
-DROP TABLE t1;
-
 SET GLOBAL innodb_purge_rseg_truncate_frequency = @saved_frequency;
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 63236ea2342..b78a103ed5b 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -5931,14 +5931,6 @@ initialize_auto_increment(dict_table_t* table, const Field* field)
 int
 ha_innobase::open(const char* name, int, uint)
 {
-	/* TODO: If trx_rollback_recovered(bool all=false) is ever
-	removed, the first-time open() must hold (or acquire and release)
-	a table lock that conflicts with trx_resurrect_table_locks(),
-	to ensure that any recovered incomplete ALTER TABLE will have been
-	rolled back. Otherwise, dict_table_t::instant could be cleared by
-	the rollback invoking dict_index_t::clear_instant_alter() while
-	open table handles exist in client connections. */
-
 	char			norm_name[FN_REFLEN];
 
 	DBUG_ENTER("ha_innobase::open");
diff --git a/storage/innobase/handler/handler0alter.cc b/storage/innobase/handler/handler0alter.cc
index 2c8328a42bb..b4e269f7a94 100644
--- a/storage/innobase/handler/handler0alter.cc
+++ b/storage/innobase/handler/handler0alter.cc
@@ -140,30 +140,6 @@ static const alter_table_operations INNOBASE_ALTER_INSTANT
 	| ALTER_RENAME_INDEX
 	| ALTER_DROP_VIRTUAL_COLUMN;
 
-/** Acquire a page latch on the possible metadata record,
-to prevent concurrent invocation of dict_index_t::clear_instant_alter()
-by purge when the table turns out to be empty.
-@param[in,out]	index	clustered index
-@param[in,out]	mtr	mini-transaction */
-static void instant_metadata_lock(dict_index_t& index, mtr_t& mtr)
-{
-	DBUG_ASSERT(index.is_primary());
-
-	if (!index.is_instant()) {
-		/* dict_index_t::clear_instant_alter() cannot be called.
-		No need for a latch. */
-		return;
-	}
-
-	btr_cur_t btr_cur;
-	btr_cur_open_at_index_side(true, &index, BTR_SEARCH_LEAF,
-				   &btr_cur, 0, &mtr);
-	ut_ad(page_cur_is_before_first(btr_cur_get_page_cur(&btr_cur)));
-	ut_ad(page_is_leaf(btr_cur_get_page(&btr_cur)));
-	ut_ad(!page_has_prev(btr_cur_get_page(&btr_cur)));
-	ut_ad(!buf_block_get_page_zip(btr_cur_get_block(&btr_cur)));
-}
-
 /** Initialize instant->field_map.
 @tparam	replace_dropped	whether to point clustered index fields
 to instant->dropped[]
@@ -242,16 +218,10 @@ inline void dict_table_t::prepare_instant(const dict_table_t& old,
 	If that is the case, the instant ALTER TABLE would keep
 	the InnoDB table in its current format. */
 
-	dict_index_t& oindex = *old.indexes.start;
+	const dict_index_t& oindex = *old.indexes.start;
 	dict_index_t& index = *indexes.start;
 	first_alter_pos = 0;
 
-	mtr_t mtr;
-	mtr.start();
-	/* Protect oindex.n_core_fields and others, so that
-	purge cannot invoke dict_index_t::clear_instant_alter(). */
-	instant_metadata_lock(oindex, mtr);
-
 	for (unsigned i = 0; i + DATA_N_SYS_COLS < old.n_cols; i++) {
 		if (col_map[i] != i) {
 			first_alter_pos = 1 + i;
@@ -424,7 +394,6 @@ found_j:
 	DBUG_ASSERT(n_dropped() >= old.n_dropped());
 	DBUG_ASSERT(index.n_core_fields == oindex.n_core_fields);
 	DBUG_ASSERT(index.n_core_null_bytes == oindex.n_core_null_bytes);
-	mtr.commit();
 }
 
 /** Adjust index metadata for instant ADD/DROP/reorder COLUMN.
@@ -444,15 +413,8 @@ inline void dict_index_t::instant_add_field(const dict_index_t& instant)
 	DBUG_ASSERT(n_uniq == instant.n_uniq);
 	DBUG_ASSERT(instant.n_fields >= n_fields);
 	DBUG_ASSERT(instant.n_nullable >= n_nullable);
-	/* dict_table_t::prepare_instant() initialized n_core_fields
-	to be equal. However, after that purge could have emptied the
-	table and invoked dict_index_t::clear_instant_alter(). */
-	DBUG_ASSERT(instant.n_core_fields <= n_core_fields);
-	DBUG_ASSERT(instant.n_core_null_bytes <= n_core_null_bytes);
-	DBUG_ASSERT(instant.n_core_fields == n_core_fields
-		    || (!is_instant() && instant.is_instant()));
-	DBUG_ASSERT(instant.n_core_null_bytes == n_core_null_bytes
-		    || (!is_instant() && instant.is_instant()));
+	DBUG_ASSERT(instant.n_core_fields == n_core_fields);
+	DBUG_ASSERT(instant.n_core_null_bytes == n_core_null_bytes);
 
 	/* instant will have all fields (including ones for columns
 	that have been or are being instantly dropped) in the same position
@@ -755,11 +717,6 @@ inline void dict_table_t::rollback_instant(
 {
 	ut_d(dict_sys.assert_locked());
 	dict_index_t* index = indexes.start;
-	mtr_t mtr;
-	mtr.start();
-	/* Prevent concurrent execution of dict_index_t::clear_instant_alter()
-	by acquiring a latch on the leftmost leaf page. */
-	instant_metadata_lock(*index, mtr);
 	/* index->is_instant() does not necessarily hold here, because
 	the table may have been emptied */
 	DBUG_ASSERT(old_n_cols >= DATA_N_SYS_COLS);
@@ -814,7 +771,6 @@ inline void dict_table_t::rollback_instant(
 	}
 
 	index->fields = old_fields;
-	mtr.commit();
 
 	while ((index = dict_table_get_next_index(index)) != NULL) {
 		if (index->to_be_dropped) {
@@ -5628,12 +5584,6 @@ static bool innobase_instant_try(
 	dict_table_t* user_table = ctx->old_table;
 
 	dict_index_t* index = dict_table_get_first_index(user_table);
-	mtr_t mtr;
-	mtr.start();
-	/* Prevent purge from calling dict_index_t::clear_instant_alter(),
-	to protect index->n_core_fields, index->table->instant and others
-	from changing during ctx->instant_column(). */
-	instant_metadata_lock(*index, mtr);
 	const unsigned n_old_fields = index->n_fields;
 	const dict_col_t* old_cols = user_table->cols;
 	DBUG_ASSERT(user_table->n_cols == ctx->old_n_cols);
@@ -5641,11 +5591,6 @@ static bool innobase_instant_try(
 	const bool metadata_changed = ctx->instant_column();
 
 	DBUG_ASSERT(index->n_fields >= n_old_fields);
-	/* Release the page latch. Between this and the next
-	btr_pcur_open_at_index_side(), data fields such as
-	index->n_core_fields and index->table->instant could change,
-	but we would handle that in empty_table: below. */
-	mtr.commit();
 	/* The table may have been emptied and may have lost its
 	'instantness' during this ALTER TABLE. */
 
@@ -5801,6 +5746,7 @@ add_all_virtual:
 	memset(roll_ptr, 0, sizeof roll_ptr);
 
 	dtuple_t* entry = index->instant_metadata(*row, ctx->heap);
+	mtr_t	mtr;
 	mtr.start();
 	index->set_modified(mtr);
 	btr_pcur_t pcur;
diff --git a/storage/innobase/row/row0purge.cc b/storage/innobase/row/row0purge.cc
index 1e8cd1ada71..d072affa11b 100644
--- a/storage/innobase/row/row0purge.cc
+++ b/storage/innobase/row/row0purge.cc
@@ -108,6 +108,7 @@ row_purge_remove_clust_if_poss_low(
 
 	mtr_t mtr;
 	mtr.start();
+	index->set_modified(mtr);
 
 	if (!row_purge_reposition_pcur(mode, node, &mtr)) {
 		/* The record was already removed. */
@@ -115,9 +116,6 @@ row_purge_remove_clust_if_poss_low(
 		return true;
 	}
 
-	ut_d(const bool was_instant = !!index->table->instant);
-	index->set_modified(mtr);
-
 	rec_t* rec = btr_pcur_get_rec(&node->pcur);
 	ulint offsets_[REC_OFFS_NORMAL_SIZE];
 	rec_offs_init(offsets_);
@@ -157,10 +155,6 @@ row_purge_remove_clust_if_poss_low(
 		}
 	}
 
-	/* Prove that dict_index_t::clear_instant_alter() was
-	not called with index->table->instant != NULL. */
-	ut_ad(!was_instant || index->table->instant);
-
 func_exit:
 	if (heap) {
 		mem_heap_free(heap);