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mysql-test/r/partition_debug_sync.result

+DROP TABLE IF EXISTS t1, t2;
+SET DEBUG_SYNC= 'RESET';
+#
+# Bug#42438: Crash ha_partition::change_table_ptr
+# Test when remove partitioning is done while drop table is waiting
+# for the table.
+# Con 1
+SET DEBUG_SYNC= 'RESET';
+CREATE TABLE t1
+(a INTEGER,
+b INTEGER NOT NULL,
+KEY (b))
+ENGINE = MYISAM
+/*!50100  PARTITION BY RANGE (a)
+(PARTITION p0 VALUES LESS THAN (2),
+PARTITION p1 VALUES LESS THAN (20),
+PARTITION p2 VALUES LESS THAN (100),
+PARTITION p3 VALUES LESS THAN MAXVALUE ) */;
+SET DEBUG_SYNC= 'alter_table_before_create_table_no_lock SIGNAL removing_partitioning WAIT_FOR waiting_for_alter';
+SET DEBUG_SYNC= 'alter_table_before_main_binlog SIGNAL partitioning_removed';
+ALTER TABLE t1 REMOVE PARTITIONING;
+# Con default
+SET DEBUG_SYNC= 'now WAIT_FOR removing_partitioning';
+SET DEBUG_SYNC= 'waiting_for_table SIGNAL waiting_for_alter';
+SET DEBUG_SYNC= 'rm_table_part2_before_delete_table WAIT_FOR partitioning_removed';
+DROP TABLE IF EXISTS t1;
+# Con 1
+SET DEBUG_SYNC= 'RESET';
+SET DEBUG_SYNC= 'RESET';
+#
+# Bug#42438: Crash ha_partition::change_table_ptr
+# Test when remove partitioning is failing due to drop table is already
+# in progress.
+CREATE TABLE t2
+(a INTEGER,
+b INTEGER NOT NULL,
+KEY (b))
+ENGINE = MYISAM
+/*!50100  PARTITION BY RANGE (a)
+(PARTITION p0 VALUES LESS THAN (2),
+PARTITION p1 VALUES LESS THAN (20),
+PARTITION p2 VALUES LESS THAN (100),
+PARTITION p3 VALUES LESS THAN MAXVALUE ) */;
+SET DEBUG_SYNC= 'before_lock_tables_takes_lock SIGNAL removing_partitions WAIT_FOR waiting_for_alter';
+SET DEBUG_SYNC= 'alter_table_before_rename_result_table WAIT_FOR delete_done';
+ALTER TABLE t2 REMOVE PARTITIONING;
+# Con default
+SET DEBUG_SYNC= 'now WAIT_FOR removing_partitions';
+SET DEBUG_SYNC= 'waiting_for_table SIGNAL waiting_for_alter';
+SET DEBUG_SYNC= 'rm_table_part2_before_binlog SIGNAL delete_done';
+DROP TABLE IF EXISTS t2;
+# Con 1
+ERROR 42S02: Table 'test.t2' doesn't exist
+SET DEBUG_SYNC= 'RESET';
+# Con default
+SET DEBUG_SYNC= 'RESET';
+End of 5.1 tests

mysql-test/t/partition_debug_sync.test

+#--disable_abort_on_error
+#
+# Test for the partition storage engine which require DEBUG_SYNC feature to
+# Created by Mattias Jonsson
+#
+--source include/have_partition.inc
+--source include/have_debug_sync.inc
+
+--disable_warnings
+DROP TABLE IF EXISTS t1, t2;
+SET DEBUG_SYNC= 'RESET';
+--enable_warnings
+
+--echo #
+--echo # Bug#42438: Crash ha_partition::change_table_ptr
+--echo # Test when remove partitioning is done while drop table is waiting
+--echo # for the table.
+connect(con1, localhost, root,,);
+--echo # Con 1
+SET DEBUG_SYNC= 'RESET';
+CREATE TABLE t1
+(a INTEGER,
+ b INTEGER NOT NULL,
+ KEY (b))
+ENGINE = MYISAM
+/*!50100  PARTITION BY RANGE (a)
+(PARTITION p0 VALUES LESS THAN (2),
+ PARTITION p1 VALUES LESS THAN (20),
+ PARTITION p2 VALUES LESS THAN (100),
+ PARTITION p3 VALUES LESS THAN MAXVALUE ) */;
+SET DEBUG_SYNC= 'alter_table_before_create_table_no_lock SIGNAL removing_partitioning WAIT_FOR waiting_for_alter';
+SET DEBUG_SYNC= 'alter_table_before_main_binlog SIGNAL partitioning_removed';
+--send ALTER TABLE t1 REMOVE PARTITIONING
+connection default;
+--echo # Con default
+SET DEBUG_SYNC= 'now WAIT_FOR removing_partitioning';
+SET DEBUG_SYNC= 'waiting_for_table SIGNAL waiting_for_alter';
+SET DEBUG_SYNC= 'rm_table_part2_before_delete_table WAIT_FOR partitioning_removed';
+DROP TABLE IF EXISTS t1;
+--echo # Con 1
+connection con1;
+--reap
+connection default;
+SET DEBUG_SYNC= 'RESET';
+connection con1;
+SET DEBUG_SYNC= 'RESET';
+
+--echo #
+--echo # Bug#42438: Crash ha_partition::change_table_ptr
+--echo # Test when remove partitioning is failing due to drop table is already
+--echo # in progress.
+CREATE TABLE t2
+(a INTEGER,
+ b INTEGER NOT NULL,
+ KEY (b))
+ENGINE = MYISAM
+/*!50100  PARTITION BY RANGE (a)
+(PARTITION p0 VALUES LESS THAN (2),
+ PARTITION p1 VALUES LESS THAN (20),
+ PARTITION p2 VALUES LESS THAN (100),
+ PARTITION p3 VALUES LESS THAN MAXVALUE ) */;
+SET DEBUG_SYNC= 'before_lock_tables_takes_lock SIGNAL removing_partitions WAIT_FOR waiting_for_alter';
+SET DEBUG_SYNC= 'alter_table_before_rename_result_table WAIT_FOR delete_done';
+--send ALTER TABLE t2 REMOVE PARTITIONING
+connection default;
+--echo # Con default
+SET DEBUG_SYNC= 'now WAIT_FOR removing_partitions';
+SET DEBUG_SYNC= 'waiting_for_table SIGNAL waiting_for_alter';
+SET DEBUG_SYNC= 'rm_table_part2_before_binlog SIGNAL delete_done';
+DROP TABLE IF EXISTS t2;
+--echo # Con 1
+connection con1;
+--error ER_NO_SUCH_TABLE
+--reap
+SET DEBUG_SYNC= 'RESET';
+disconnect con1;
+connection default;
+--echo # Con default
+SET DEBUG_SYNC= 'RESET';
+
+--echo End of 5.1 tests

sql/ha_partition.cc

@@ -1746,13 +1746,23 @@ void ha_partition::update_create_info(HA_CREATE_INFO *create_info)
 
 void ha_partition::change_table_ptr(TABLE *table_arg, TABLE_SHARE *share)
 {
-  handler **file_array= m_file;
+  handler **file_array;
   table= table_arg;
   table_share= share;
-  do
+  /*
+    m_file can be NULL when using an old cached table in DROP TABLE, when the
+    table just has REMOVED PARTITIONING, see Bug#42438
+  */
+  if (m_file)
   {
-    (*file_array)->change_table_ptr(table_arg, share);
-  } while (*(++file_array));
+    file_array= m_file;
+    DBUG_ASSERT(*file_array);
+    do
+    {
+      (*file_array)->change_table_ptr(table_arg, share);
+    } while (*(++file_array));
+  }
+
   if (m_added_file && m_added_file[0])
   {
     /* if in middle of a drop/rename etc */
@@ -6055,7 +6065,13 @@ void ha_partition::print_error(int error, myf errflag)
   if (error == HA_ERR_NO_PARTITION_FOUND)
     m_part_info->print_no_partition_found(table);
   else
-    m_file[m_last_part]->print_error(error, errflag);
+  {
+    /* In case m_file has not been initialized, like in bug#42438 */
+    if (m_file)
+      m_file[m_last_part]->print_error(error, errflag);
+    else
+      handler::print_error(error, errflag);
+  }
   DBUG_VOID_RETURN;
 }
 
@@ -6065,7 +6081,12 @@ bool ha_partition::get_error_message(int error, String *buf)
   DBUG_ENTER("ha_partition::get_error_message");
 
   /* Should probably look for my own errors first */
-  DBUG_RETURN(m_file[m_last_part]->get_error_message(error, buf));
+
+  /* In case m_file has not been initialized, like in bug#42438 */
+  if (m_file)
+    DBUG_RETURN(m_file[m_last_part]->get_error_message(error, buf));
+  DBUG_RETURN(handler::get_error_message(error, buf));
+
 }
 
 

sql/sql_base.cc

@@ -2169,6 +2169,7 @@ void wait_for_condition(THD *thd, pthread_mutex_t *mutex, pthread_cond_t *cond)
   proc_info=thd->proc_info;
   thd_proc_info(thd, "Waiting for table");
   DBUG_ENTER("wait_for_condition");
+  DEBUG_SYNC(thd, "waiting_for_table");
   if (!thd->killed)
     (void) pthread_cond_wait(cond, mutex);
 

sql/sql_table.cc

@@ -22,6 +22,9 @@
 #include "sp_head.h"
 #include "sql_trigger.h"
 #include "sql_show.h"
+#if defined(ENABLED_DEBUG_SYNC)
+#include "debug_sync.h"
+#endif
 
 #ifdef __WIN__
 #include <io.h>
@@ -1889,22 +1892,10 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
 
   pthread_mutex_lock(&LOCK_open);
 
-  /*
-    If we have the table in the definition cache, we don't have to check the
-    .frm file to find if the table is a normal table (not view) and what
-    engine to use.
-  */
-
+  /* Disable drop of enabled log tables, must be done before name locking */
   for (table= tables; table; table= table->next_local)
   {
-    TABLE_SHARE *share;
-    table->db_type= NULL;
-    if ((share= get_cached_table_share(table->db, table->table_name)))
-      table->db_type= share->db_type();
-
-    /* Disable drop of enabled log tables */
-    if (share && (share->table_category == TABLE_CATEGORY_PERFORMANCE) &&
-        check_if_log_table(table->db_length, table->db,
+    if (check_if_log_table(table->db_length, table->db,
                            table->table_name_length, table->table_name, 1))
     {
       my_error(ER_BAD_LOG_STATEMENT, MYF(0), "DROP");
@@ -1923,7 +1914,7 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
   {
     char *db=table->db;
     handlerton *table_type;
-    enum legacy_db_type frm_db_type;
+    enum legacy_db_type frm_db_type= DB_TYPE_UNKNOWN;
 
     DBUG_PRINT("table", ("table_l: '%s'.'%s'  table: 0x%lx  s: 0x%lx",
                          table->db, table->table_name, (long) table->table,
@@ -1988,7 +1979,6 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
       built_query.append("`,");
     }
 
-    table_type= table->db_type;
     if (!drop_temporary)
     {
       TABLE *locked_table;
@@ -2015,9 +2005,9 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
                                         table->internal_tmp_table ?
                                         FN_IS_TMP : 0);
     }
+    DEBUG_SYNC(thd, "rm_table_part2_before_delete_table");
     if (drop_temporary ||
-        ((table_type == NULL &&        
-         access(path, F_OK) &&
+        ((access(path, F_OK) &&
           ha_create_table_from_engine(thd, db, alias)) ||
          (!drop_view &&
           mysql_frm_type(thd, path, &frm_db_type) != FRMTYPE_TABLE)))
@@ -2033,15 +2023,25 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
     else
     {
       char *end;
-      if (table_type == NULL)
+      /*
+        Cannot use the db_type from the table, since that might have changed
+        while waiting for the exclusive name lock. We are under LOCK_open,
+        so reading from the frm-file is safe.
+      */
+      if (frm_db_type == DB_TYPE_UNKNOWN)
       {
-	mysql_frm_type(thd, path, &frm_db_type);
-        table_type= ha_resolve_by_legacy_type(thd, frm_db_type);
+        mysql_frm_type(thd, path, &frm_db_type);
+        DBUG_PRINT("info", ("frm_db_type %d from %s", frm_db_type, path));
       }
+      table_type= ha_resolve_by_legacy_type(thd, frm_db_type);
       // Remove extension for delete
       *(end= path + path_length - reg_ext_length)= '\0';
+      DBUG_PRINT("info", ("deleting table of type %d",
+                          (table_type ? table_type->db_type : 0)));
       error= ha_delete_table(thd, table_type, path, db, table->table_name,
                              !dont_log_query);
+
+      /* No error if non existent table and 'IF EXIST' clause or view */
       if ((error == ENOENT || error == HA_ERR_NO_SUCH_TABLE) && 
 	  (if_exists || table_type == NULL))
       {
@@ -2081,6 +2081,7 @@ int mysql_rm_table_part2(THD *thd, TABLE_LIST *tables, bool if_exists,
     on the table name.
   */
   pthread_mutex_unlock(&LOCK_open);
+  DEBUG_SYNC(thd, "rm_table_part2_before_binlog");
   thd->thread_specific_used|= tmp_table_deleted;
   error= 0;
   if (wrong_tables.length())
@@ -7120,6 +7121,7 @@ view_err:
   else
     create_info->data_file_name=create_info->index_file_name=0;
 
+  DEBUG_SYNC(thd, "alter_table_before_create_table_no_lock");
   /*
     Create a table with a temporary name.
     With create_info->frm_only == 1 this creates a .frm file only.
@@ -7320,6 +7322,7 @@ view_err:
     intern_close_table(new_table);
     my_free(new_table,MYF(0));
   }
+  DEBUG_SYNC(thd, "alter_table_before_rename_result_table");
   VOID(pthread_mutex_lock(&LOCK_open));
   if (error)
   {
@@ -7462,6 +7465,7 @@ view_err:
   thd_proc_info(thd, "end");
 
   DBUG_EXECUTE_IF("sleep_alter_before_main_binlog", my_sleep(6000000););
+  DEBUG_SYNC(thd, "alter_table_before_main_binlog");
 
   ha_binlog_log_query(thd, create_info->db_type, LOGCOM_ALTER_TABLE,
                       thd->query(), thd->query_length(),