PS-9222 ALTER TABLE ALGORITHM=INSTANT FIX #2

https://perconadev.atlassian.net/browse/PS-9222 Problem ======= When writing to the redo log, an issue of column order change not being recorded with INSTANT DDL was fixed by checking if the fields are also reordered, then adding the columns into the list. However when calculating the size of the buffer this fix doesn't take account the extra fields that may be logged, and causing the assertion on the buffer size failed eventually. Solution ======== To calculate the buffer size correctly, we move the logic of finding reordered fiedls before buffer size calculation, then count the number of fields with the same logic when deciding if a field needs to be logged.
percona · Jun 28, 2024 · f8b1da5 · f8b1da5
1 parent 366031e
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diff --git a/mysql-test/suite/innodb/r/instant_alter_stored_column_order.result b/mysql-test/suite/innodb/r/instant_alter_stored_column_order.result
@@ -0,0 +1,46 @@
+without prefix field in the index
+CREATE TABLE t1 (c1 TINYTEXT COLLATE ascii_bin NOT NULL, c2 DATETIME(3) NOT NULL, c3 TEXT, UNIQUE KEY (c1(30)));
+INSERT INTO t1 (c1, c2, c3) VALUE ('k1','2021-12-21','something');
+INSERT INTO t1 (c1, c2, c3) VALUE ('k3','2021-12-21','something else');
+ALTER TABLE t1
+CHANGE c2 c2 DATETIME(3) NOT NULL AFTER c3,
+ADD COLUMN c4 VARCHAR(18) NOT NULL,
+ALGORITHM=INSTANT;
+# Make sure nothing gets flushed on disk
+SET GLOBAL innodb_log_checkpoint_now = ON;
+SET GLOBAL innodb_page_cleaner_disabled_debug = 1;
+SET GLOBAL innodb_dict_stats_disabled_debug = 1;
+SET GLOBAL innodb_master_thread_disabled_debug = 1;
+SET GLOBAL innodb_checkpoint_disabled = ON;
+UPDATE t1 SET c4 = 'value' WHERE c1 = 'k1';
+# Restart the server and reload the table to see if tables are corrupted.
+# Kill and restart
+# Run a select to confirm that the database started up successfully
+SELECT * FROM t1;
+c1	c3	c2	c4
+k1	something	2021-12-21 00:00:00.000	value
+k3	something else	2021-12-21 00:00:00.000	
+DROP TABLE t1;
+with prefix field in the index
+CREATE TABLE t1 (c1 TINYTEXT COLLATE ascii_bin NOT NULL, c2 DATETIME(3) NOT NULL, c3 TEXT, PRIMARY KEY (c1(30)));
+INSERT INTO t1 (c1, c2, c3) VALUE ('k1','2021-12-21','something');
+INSERT INTO t1 (c1, c2, c3) VALUE ('k3','2021-12-21','something else');
+ALTER TABLE t1 
+CHANGE c2 c2 DATETIME(3) NOT NULL AFTER c3,
+ADD COLUMN c4 VARCHAR(18) NOT NULL,
+ALGORITHM=INSTANT;
+# Make sure nothing gets flushed on disk
+SET GLOBAL innodb_log_checkpoint_now = ON;
+SET GLOBAL innodb_page_cleaner_disabled_debug = 1;
+SET GLOBAL innodb_dict_stats_disabled_debug = 1;
+SET GLOBAL innodb_master_thread_disabled_debug = 1;
+SET GLOBAL innodb_checkpoint_disabled = ON;
+UPDATE t1 SET c4 = 'value' WHERE c1 = 'k1';
+# Restart the server and reload the table to see if tables are corrupted.
+# Kill and restart
+# Run a select to confirm that the database started up successfully
+SELECT * FROM t1;
+c1	c3	c2	c4
+k1	something	2021-12-21 00:00:00.000	value
+k3	something else	2021-12-21 00:00:00.000	
+DROP TABLE t1;
diff --git a/mysql-test/suite/innodb/t/instant_alter_stored_column_order.test b/mysql-test/suite/innodb/t/instant_alter_stored_column_order.test
@@ -0,0 +1,57 @@
+# PS-9222 Testing if ALGORITHM=INSTANT crashes server
+
+--echo without prefix field in the index
+CREATE TABLE t1 (c1 TINYTEXT COLLATE ascii_bin NOT NULL, c2 DATETIME(3) NOT NULL, c3 TEXT, UNIQUE KEY (c1(30)));
+INSERT INTO t1 (c1, c2, c3) VALUE ('k1','2021-12-21','something');
+INSERT INTO t1 (c1, c2, c3) VALUE ('k3','2021-12-21','something else');
+
+ALTER TABLE t1
+CHANGE c2 c2 DATETIME(3) NOT NULL AFTER c3,
+ADD COLUMN c4 VARCHAR(18) NOT NULL,
+ALGORITHM=INSTANT;
+
+--echo # Make sure nothing gets flushed on disk
+SET GLOBAL innodb_log_checkpoint_now = ON;
+SET GLOBAL innodb_page_cleaner_disabled_debug = 1;
+SET GLOBAL innodb_dict_stats_disabled_debug = 1;
+SET GLOBAL innodb_master_thread_disabled_debug = 1;
+SET GLOBAL innodb_checkpoint_disabled = ON;
+
+UPDATE t1 SET c4 = 'value' WHERE c1 = 'k1';
+
+--echo # Restart the server and reload the table to see if tables are corrupted.
+--source include/kill_and_restart_mysqld.inc
+
+-- echo # Run a select to confirm that the database started up successfully
+SELECT * FROM t1;
+
+# cleanup
+DROP TABLE t1;
+
+--echo with prefix field in the index
+CREATE TABLE t1 (c1 TINYTEXT COLLATE ascii_bin NOT NULL, c2 DATETIME(3) NOT NULL, c3 TEXT, PRIMARY KEY (c1(30)));
+INSERT INTO t1 (c1, c2, c3) VALUE ('k1','2021-12-21','something');
+INSERT INTO t1 (c1, c2, c3) VALUE ('k3','2021-12-21','something else');
+
+ALTER TABLE t1 
+CHANGE c2 c2 DATETIME(3) NOT NULL AFTER c3,
+ADD COLUMN c4 VARCHAR(18) NOT NULL,
+ALGORITHM=INSTANT;
+
+--echo # Make sure nothing gets flushed on disk
+SET GLOBAL innodb_log_checkpoint_now = ON;
+SET GLOBAL innodb_page_cleaner_disabled_debug = 1;
+SET GLOBAL innodb_dict_stats_disabled_debug = 1;
+SET GLOBAL innodb_master_thread_disabled_debug = 1;
+SET GLOBAL innodb_checkpoint_disabled = ON;
+
+UPDATE t1 SET c4 = 'value' WHERE c1 = 'k1';
+
+--echo # Restart the server and reload the table to see if tables are corrupted.
+--source include/kill_and_restart_mysqld.inc
+
+-- echo # Run a select to confirm that the database started up successfully
+SELECT * FROM t1;
+
+# cleanup
+DROP TABLE t1;
diff --git a/storage/innobase/mtr/mtr0log.cc b/storage/innobase/mtr/mtr0log.cc
@@ -515,18 +515,29 @@ constexpr size_t inst_col_info_size = 6;
 @param[in]   is_comp       true if COMP
 @param[in]   is_versioned  if table has row versions
 @param[in]   is_instant    true if table has INSTANT cols
+@param[in]   changed_order array indicating fields changed position
 @param[out]  size_needed   total size needed on REDO LOG */
 static void log_index_get_size_needed(const dict_index_t *index, size_t size,
                                       uint16_t n, bool is_comp,
                                       bool is_versioned, bool is_instant,
-                                      size_t &size_needed) {
-  auto size_for_versioned_fields = [](const dict_index_t *ind) {
+                                      const std::unique_ptr<bool[]>&
+                                      changed_order, size_t &size_needed) {
+  auto size_for_versioned_fields = [n,
+                                    &changed_order](const dict_index_t *ind) {
     size_t _size = 0;
     /* 2 bytes for number of columns with version */
     _size += 2;
 
-    size_t n_versioned_fields = ind->table->get_n_instant_add_cols() +
-                                ind->table->get_n_instant_drop_cols();
+    size_t n_versioned_fields = 0;
+    for (size_t i = 0; i < n; i++) {
+      dict_field_t *field = ind->get_field(i);
+      const dict_col_t *col = field->col;
+      if (col->is_instant_added() || col->is_instant_dropped() ||
+          changed_order[i]) {
+        n_versioned_fields += 1;
+      }
+    }
+
     ut_ad(n_versioned_fields != 0);
 
     _size += n_versioned_fields * inst_col_info_size;
@@ -644,6 +655,7 @@ static bool close_and_reopen_log(byte *&log_ptr, const byte *&log_start,
                                  const byte *&log_end, mtr_t *&mtr,
                                  size_t &alloc, size_t &total) {
   mlog_close(mtr, log_ptr);
+
   ut_a(total > (ulint)(log_ptr - log_start));
   total -= log_ptr - log_start;
   alloc = total;
@@ -673,7 +685,8 @@ template <typename F>
 @param[in]  func          callback to check size reopen log buffer */
 static bool log_index_fields(const dict_index_t *index, uint16_t n,
                              bool is_versioned, std::vector<dict_field_t *> &f,
-                             bool *changed_order, byte *&log_ptr, F &func) {
+                             const std::unique_ptr<bool[]> &changed_order,
+                             byte *&log_ptr, F &func) {
   /* Write metadata for each field. Log the fields in their logical order. */
   for (size_t i = 0; i < n; i++) {
     dict_field_t *field = index->get_field(i);
@@ -799,9 +812,36 @@ bool mlog_open_and_write_index(mtr_t *mtr, const byte *rec,
     n = DICT_INDEX_SPATIAL_NODEPTR_SIZE;
   }
 
+  /* Ordinal position of an existing field can't be changed with INSTANT
+  algorithm. But when it is combined with ADD/DROP COLUMN, ordinal position
+  of a filed can be changed. This bool array of size #fields in index,
+  represents if ordinal position of an existing filed is changed. */
+
+  // Move the logic to find columns that changed order before calculating
+  // the buffer size
+  std::unique_ptr<bool[]> fields_with_changed_order = nullptr;
+  if (is_versioned) {
+    fields_with_changed_order = std::make_unique<bool[]>(n);
+
+    uint16_t phy_pos = 0;
+    for (size_t i = 0; i < n; i++) {
+      dict_field_t *field = index->get_field(i);
+      const dict_col_t *col = field->col;
+
+      if (col->is_instant_added() || col->is_instant_dropped()) {
+        continue;
+      }
+      if (col->get_col_phy_pos() >= phy_pos) {
+        phy_pos = col->get_col_phy_pos();
+      } else {
+        fields_with_changed_order[i] = true;
+      }
+    }
+  }
+
   size_t size_needed = 0;
   log_index_get_size_needed(index, size, n, is_comp, is_versioned, is_instant,
-                            size_needed);
+                            fields_with_changed_order, size_needed);
   size_t total = size_needed;
   size_t alloc = total;
   if (alloc > mtr_buf_t::MAX_DATA_SIZE) {
@@ -846,37 +886,10 @@ bool mlog_open_and_write_index(mtr_t *mtr, const byte *rec,
     return true;
   };
 
-  /* Ordinal position of an existing field can't be changed with INSTANT
-  algorithm. But when it is combined with ADD/DROP COLUMN, ordinal position
-  of a filed can be changed. This bool array of size #fields in index,
-  represents if ordinal position of an existing filed is changed. */
-  bool *fields_with_changed_order = nullptr;
-  if (is_versioned) {
-    fields_with_changed_order = new bool[n];
-    memset(fields_with_changed_order, false, (sizeof(bool) * n));
-
-    uint16_t phy_pos = 0;
-    for (size_t i = 0; i < n; i++) {
-      dict_field_t *field = index->get_field(i);
-      const dict_col_t *col = field->col;
-
-      if (col->is_instant_added() || col->is_instant_dropped()) {
-        continue;
-      } else if (col->get_col_phy_pos() >= phy_pos) {
-        phy_pos = col->get_col_phy_pos();
-      } else {
-        fields_with_changed_order[i] = true;
-      }
-    }
-  }
-
   if (is_comp) {
     /* Write fields info. */
     if (!log_index_fields(index, n, is_versioned, instant_fields_to_log,
                           fields_with_changed_order, log_ptr, f)) {
-      if (is_versioned) {
-        delete[] fields_with_changed_order;
-      }
       return false;
     }
   } else if (is_versioned) {
@@ -890,10 +903,6 @@ bool mlog_open_and_write_index(mtr_t *mtr, const byte *rec,
     }
   }
 
-  if (is_versioned) {
-    delete[] fields_with_changed_order;
-  }
-
   if (!instant_fields_to_log.empty()) {
     ut_ad(is_versioned);
     /* Log INSTANT ADD/DROP fields */