Re: [Maria-developers] 250bc3b6d74: Ensure that table is truly dropped when using DROP TABLE

12 Jun 2020

Hi, Michael!

On Jun 11, Michael Widenius wrote:
...
revision-id: 250bc3b6d74 (mariadb-10.5.2-390-g250bc3b6d74)
parent(s): ba2c2cfb20e
author: Michael Widenius <michael.widenus@gmail.com>
committer: Michael Widenius <michael.widenus@gmail.com>
timestamp: 2020-06-11 11:33:55 +0300
message:
Ensure that table is truly dropped when using DROP TABLE
MDEV-11412 AliSQL: [Feature] Issue#34 Support force drop table
please, put this line ^^^ first in the comment comment.
...
The used code is largely based on code from Tencent
The problem is that in some rare cases there may be a conflict between .frm
files and the files in the storage engine. In this case the DROP TABLE
was not able to properly drop the table.
Some MariaDB/MySQL forks has solved this by adding a FORCE option to
TSQL? Or some other fork?
...
DROP TABLE. After some discussion among MariaDB developers, we concluded
that users expects that DROP TABLE should always work, even if the
table would not be consistent. There should not be a need to use a
separate keyword to ensure that the table is really deleted.
The used solution is:
- If a .frm table doesn't exists, try dropping the table from all storage
  engines.
- If the .frm table exists but the table does not exist in the engine
  try dropping the table from all storage engines.
I don't see why is that needed, if .frm exists, it tells exactly what
storage engine to use, there is no point in trying other engines.
...
- Update storage engines using many table files (.CVS, MyISAM, Aria) to
  succeed with the drop even if some of the files are missing.
- Add HTON_AUTOMATIC_DELETE_TABLE to handlerton's where delete_table()
  is not needed and always succeed. This is used by ha_delete_table_force()
  to know which handlers to ignore when trying to drop a table without
  a .frm file.
The disadvantage of this solution is that a DROP TABLE on a non existing
table will be a bit slower as we have to ask all active storage engines
if they know anything about the table.
Other things:
- Added a new flag MY_IGNORE_ENOENT to my_delete() to not give an error
  if the file doesn't exist. This simplifies some of the code.
- Don't clear thd->error in ha_delete_table() if there was an active
  error. This is a bug fix.
- handler::delete_table() will not abort if first file doesn't exists.
  This is bug fix to handle the case when a drop table was aborted in
  the middle.
- Cleaned up mysql_rm_table_no_locks() to ensure that if_exists uses
  same code path as when it's not used.
- Use non_existing_Table_error() to detect if table didn't exists.
  Old code used different errors tests in different position.
- Table_triggers_list::drop_all_triggers() now drops trigger file if
  it can't be parsed instead of leaving it hanging around (bug fix)
- InnoDB doesn't anymore print error about .frm file out of sync with
  InnoDB directory if .frm file does not exists. This change was required
  to be able to try to drop an InnoDB file when .frm doesn't exists.
- Fixed bug in mi_delete_table() where the .MYD file would not be dropped
  if the .MYI file didn't exists.
- Fixed memory leak in Mroonga when deleting non existing table
- Fixed memory leak in Connect when deleting non existing table
Bugs fixed introduced by the original version of this commit:
MDEV-22826 Presence of Spider prevents tables from being force-deleted from
           other engines
I don't think this part of the comment makes any sense, when one looks
through git history there is no "original version of this commit".

It's like a rolled back transaction, that value did not exist, unless
you use READ UNCOMMITTED :)
...

diff --git a/mysql-test/main/drop_table_force.test b/mysql-test/main/drop_table_force.test
new file mode 100644
index 00000000000..8fdd79465b7
--- /dev/null
+++ b/mysql-test/main/drop_table_force.test
@@ -0,1 +1,197 @@
 +--source include/have_log_bin.inc
+--source include/have_innodb.inc
+
+#
+# This test is based on the orginal test from Tencent for DROP TABLE ... FORCE
+# In MariaDB we did reuse the code but MariaDB does not require the FORCE
+# keyword to drop a table even if the .frm file or some engine files are
+# missing.
+# To make it easy to see the differences between the orginal code and
+# the new one, we have left some references to the original test case
+#
+
+CALL mtr.add_suppression("Operating system error number");
+CALL mtr.add_suppression("The error means the system cannot");
+CALL mtr.add_suppression("returned OS error 71");
not sure it's a good idea, error numbers aren't very portable, this will
blow up some day like a time bomb
...
+
+let $DATADIR= `select @@datadir`;
+
+--echo #Test1: table with missing .ibd can be dropped directly
+# drop table without ibd
+create table t1(a int)engine=innodb;
+--remove_file $DATADIR/test/t1.ibd
+drop table t1;
+--list_files  $DATADIR/test/
+
+# Original DROP TABLE .. FORCE required SUPER privilege. MariaDB doesn't
+--echo # Test droping table without frm without super privilege
+
+# create table t1 and rm frm
+create table t1(a int) engine=innodb;
+--remove_file $DATADIR/test/t1.frm
+
+# create test user
+create user test identified by '123456';
+grant all privileges on test.t1 to 'test'@'%'identified by '123456' with grant option;
why with grant option?
better remove it if it's not essential for drop to work.
if it is essential, why is it?
...
+
+# connect as test
+connect (con_test, localhost, test,'123456', );
+--connection con_test
+
+# drop table with user test
+drop table t1;
+--error ER_BAD_TABLE_ERROR
+drop table t1;
+
+# connect as root
+--connection default
+
+--disconnect con_test
+drop user test;
+
+# check files in datadir about t1
+--list_files  $DATADIR/test/
+
+--echo #Test4: drop table can drop consistent table as well
+create table t1(a int) engine=innodb;
+drop table t1;
aha, so it works! :)
...
+
+# check files in datadir about t1
+--list_files  $DATADIR/test/
+
+--echo #Test5: drop table with triger, and with missing frm
+# create table t1 with triger and rm frm
+create table t1(a int)engine=innodb;
+create trigger t1_trg before insert on t1 for each row begin end;
+
+let $DATADIR= `select @@datadir`;
+--remove_file $DATADIR/test/t1.frm
+
+drop table t1;
+--error ER_BAD_TABLE_ERROR
+drop table t1;
+
+# check files in datadir about t1
+--list_files  $DATADIR/test/
+
+--echo #Test6: table with foreign key references can not be dropped
+# create table with foreign key reference and rm frm
+CREATE TABLE parent (id INT NOT NULL, PRIMARY KEY (id)) ENGINE=INNODB;
+CREATE TABLE child (id INT, parent_id INT, INDEX par_ind (parent_id), FOREIGN KEY (parent_id) REFERENCES parent(id) ON DELETE CASCADE) ENGINE=INNODB;
+--remove_file $DATADIR/test/parent.frm
+
+# parent can not be dropped when there are foreign key references
+--error ER_ROW_IS_REFERENCED_2
+drop table parent;
+
+# parent can be dropped when there are no foreign key references
+drop table child;
+drop table parent;
+
+# check files in datadir about child and parent
+--list_files  $DATADIR/test/
+
+--echo #Test7: drop table twice
+create table t1(a int)engine=innodb;
+--remove_file $DATADIR/test/t1.frm
+
+# first drop table will success
+drop table t1;
+
+# check files in datadir about t1
+--list_files  $DATADIR/test/
+
+# second drop with if exists will also ok
+drop table if exists t1;
+
+# check files in datadir about t1
+--list_files  $DATADIR/test/
+
+--echo #Test8: check compatibility with if exists
+create table t1(a int)engine=innodb;
+--remove_file $DATADIR/test/t1.frm
+
+# first drop will success
+drop table t1;
+
+# check files in datadir about t1
+--list_files  $DATADIR/test/
+
+# second drop with if exists will success
+drop table if exists t1;
you've just tested it in Test7, haven't you?
...
+
+--echo #Test9: check compatibility with restrict/cascade
+# create table with foreign key reference and rm frm
+CREATE TABLE parent (id INT NOT NULL, PRIMARY KEY (id)) ENGINE=INNODB;
+CREATE TABLE child (id INT, parent_id INT, INDEX par_ind (parent_id), FOREIGN KEY (parent_id) REFERENCES parent(id) ON DELETE CASCADE) ENGINE=INNODB;
+
+# parent can not be dropped when there are froeign key references
typo "foreign"
...
+--error ER_ROW_IS_REFERENCED_2
+drop table parent;
+--error ER_ROW_IS_REFERENCED_2
+drop table parent restrict;
+--error ER_ROW_IS_REFERENCED_2
+drop table parent cascade;
+--error ER_ROW_IS_REFERENCED_2
+drop table parent;
+--error ER_ROW_IS_REFERENCED_2
+drop table parent restrict;
+--error ER_ROW_IS_REFERENCED_2
+drop table parent cascade;
+
+# parent can be dropped when there are no foreign key references
+drop table child;
+drop table parent;
+
+--echo #Test10: drop non-innodb engine table returns ok
+# create myisam table t1 and rm .frm
+create table t1(a int) engine=myisam;
+--remove_file $DATADIR/test/t1.frm
+--replace_result \\ /
+drop table t1;
+
+# create myisam table t1 and rm .MYD
+create table t1(a int) engine=myisam;
+--remove_file $DATADIR/test/t1.MYD
+--replace_result \\ /
+drop table t1;
+
+# create myisam table t1 and rm .MYI
+create table t1(a int) engine=myisam;
+--remove_file $DATADIR/test/t1.MYI
+--replace_result \\ /
+drop table t1;
+--list_files  $DATADIR/test/
+
+# create Aria table t1 and rm .frm and .MAD
+create table t1(a int) engine=aria;
+--remove_file $DATADIR/test/t1.frm
+--remove_file $DATADIR/test/t1.MAD
+--list_files  $DATADIR/test/
+--error ER_BAD_TABLE_ERROR
+drop table t1;
+--replace_result \\ /
+show warnings;
+--list_files  $DATADIR/test/
+
+# create Aria table t2 and rm .frm and .MAI
+create table t2(a int) engine=aria;
+flush tables;
+--remove_file $DATADIR/test/t2.frm
+--remove_file $DATADIR/test/t2.MAI
+--list_files  $DATADIR/test/
+--error ER_BAD_TABLE_ERROR
+drop table t2;
+--replace_result \\ /
+show warnings;
+--list_files  $DATADIR/test/
+
+# create Aria table t2 and rm .MAI and .MAD
+create table t2(a int) engine=aria;
+flush tables;
+--remove_file $DATADIR/test/t2.MAD
+--remove_file $DATADIR/test/t2.MAI
+--list_files  $DATADIR/test/
+--replace_result \\ /
+drop table t2;
may be csv and archive tests too?
...
diff --git a/sql/handler.cc b/sql/handler.cc
index 1af0157783e..5dd02d057c7 100644
--- a/sql/handler.cc
+++ b/sql/handler.cc
@@ -2674,26 +2712,34 @@ const char *get_canonical_filename(handler *file, const char *path,
 }
-/** delete a table in the engine
+/**
+   Delete a table in the engine
+   @return 0   Table was deleted
+   @return -1  Table didn't exists, no error given
+   @return #   Error from table handler
+
   @note
   ENOENT and HA_ERR_NO_SUCH_TABLE are not considered errors.
-  The .frm file will be deleted only if we return 0.
+  The .frm file should be deleted by the caller only if we return <= 0.
 */
+
 int ha_delete_table(THD *thd, handlerton *table_type, const char *path,
-                    const LEX_CSTRING *db, const LEX_CSTRING *alias, bool generate_warning)
+                    const LEX_CSTRING *db, const LEX_CSTRING *alias,
+                    bool generate_warning)
 {
   handler *file;
   char tmp_path[FN_REFLEN];
   int error;
   TABLE dummy_table;
   TABLE_SHARE dummy_share;
+  bool is_error= thd->is_error();
   DBUG_ENTER("ha_delete_table");
/* table_type is NULL in ALTER TABLE when renaming only .frm files */
   if (table_type == NULL || table_type == view_pseudo_hton ||
       ! (file=get_new_handler((TABLE_SHARE*)0, thd->mem_root, table_type)))
-    DBUG_RETURN(0);
+    DBUG_RETURN(-1);
"Table didn't exists, no error given"?
if get_new_handler() fails it's OOM.
...
bzero((char*) &dummy_table, sizeof(dummy_table));
   bzero((char*) &dummy_share, sizeof(dummy_share));
@@ -2723,8 +2769,10 @@ int ha_delete_table(THD *thd, handlerton *table_type, const char *path,
     }
     if (intercept)
     {
+      /* Clear error if we got it in this function */
+      if (!is_error)
       thd->clear_error();
this is generally a wrong approach. One should use push_internal_handler
to silence errors, not thd->is_error() or thd->clear_error().

In this particilar case there will be no errors if there was no error
before ha_delete_table() - which is correct. But if there was an error
before, this will leave spurious and confusing errors in `SHOW WARNINGS`
output.
...
-      error= 0;
+      error= -1;
     }
   }
   delete file;
@@ -4365,45 +4413,63 @@ uint handler::get_dup_key(int error)
@note
     We assume that the handler may return more extensions than
-    was actually used for the file.
+    was actually used for the file. We also assume that the first
+    extension is the most important one. If this exist and we can't delete
+    that one we will abort the delete.
after "the most important one" you can add "(see the comment near
handlerton::tablefile_extensions)"
...
+    If the first one doesn't exists, we have to try to delete all other
"doesn't exist"
...
+    extension as there is chance that the server had crashed between
+    the delete of the first file and the next
@retval
     0   If we successfully deleted at least one file from base_ext and
     didn't get any other errors than ENOENT
+
   @retval
     !0  Error
 */
+
 int handler::delete_table(const char *name)
 {
-  int saved_error= 0;
-  int error= 0;
-  int enoent_or_zero;
+  int saved_error= ENOENT;
+  bool abort_if_first_file_error= 1;
+  bool some_file_deleted= 0;
+  DBUG_ENTER("handler::delete_table");
+  // For discovery tables, it's ok if first file doesn't exists
why would that be ok?
...
if (ht->discover_table)
-    enoent_or_zero= 0; // the table may not exist in the engine, it's ok
-  else
-    enoent_or_zero= ENOENT;  // the first file of bas_ext() *must* exist
+  {
+    abort_if_first_file_error= 0;
+    saved_error= 0;
+    if (!bas_ext())
+    {
+      DBUG_ASSERT(ht->flags & HTON_AUTOMATIC_DELETE_TABLE);
+      DBUG_RETURN(0);                           // Drop succeded
+    }
+  }
for (const char **ext= bas_ext(); *ext ; ext++)
   {
+    int error;
-    if (mysql_file_delete_with_symlink(key_file_misc, name, *ext, 0))
+    if ((error= mysql_file_delete_with_symlink(key_file_misc, name, *ext,
+                                              MYF(0))))
why do you need this `error` variable, if you never use it?
...
{
       if (my_errno != ENOENT)
       {
+        saved_error= my_errno;
         /*
-          If error on the first existing file, return the error.
+          If error other than file not found on the first existing file,
+          return the error.
           Otherwise delete as much as possible.
         */
-        if (enoent_or_zero)
-          return my_errno;
-        saved_error= my_errno;
+        if (abort_if_first_file_error)
+          DBUG_RETURN(saved_error);
       }
     }
     else
-      enoent_or_zero= 0;                        // No error for ENOENT
-    error= enoent_or_zero;
+      some_file_deleted= 1;
+    abort_if_first_file_error= 0;
   }
-  return saved_error ? saved_error : error;
+  DBUG_RETURN(some_file_deleted && saved_error == ENOENT ? 0 : saved_error);
 }
@@ -4439,5 +4505,20 @@ void handler::drop_table(const char *name)
/**
+   Return true if the error from drop table means that the
+   table didn't exists
+*/
+
+bool non_existing_table_error(int error)
+{
+  return (error == ENOENT || error == HA_ERR_NO_SUCH_TABLE ||
+          error == HA_ERR_UNSUPPORTED ||
+          error == ER_NO_SUCH_TABLE ||
+          error == ER_NO_SUCH_TABLE_IN_ENGINE ||
+          error == ER_WRONG_OBJECT);
+}
this should, I believe, be inline in handler.h
...
+
+
+/**
   Performs checks upon the table.
@@ -4899,5 +4981,89 @@ handler::ha_drop_table(const char *name)
/**
+   Structure used during force drop table.
+*/
+
+struct st_force_drop_table_params
+{
+  const char *path;
+  const LEX_CSTRING *db;
+  const LEX_CSTRING *alias;
+  bool generate_warning;
+  int error;
+};
+
+
+/**
+   Try to delete table from a given plugin
+   Table types with discovery is ignored as these .frm files would have
+   been created during discovery and thus doesn't need to be found
+   for drop table force
+*/
+
+static my_bool delete_table_force(THD *thd, plugin_ref plugin, void *arg)
+{
+  handlerton *hton = plugin_hton(plugin);
+  st_force_drop_table_params *param = (st_force_drop_table_params *)arg;
+
+  /*
+    We have to ignore HEAP tables as these may not have been created yet
+    We also remove engines that is using discovery (as these will recrate
+    any missing .frm if needed) and tables marked with
+    HTON_AUTOMATIC_DELETE_TABLE as for these we can't check if the table
+    ever existed.
+  */
+  if (!hton->discover_table && hton->db_type != DB_TYPE_HEAP &&
+      !(hton->flags & HTON_AUTOMATIC_DELETE_TABLE))
+  {
+    int error;
+    error= ha_delete_table(thd, hton, param->path, param->db,
+                           param->alias, param->generate_warning);
This is doing a a lot of extra work. dummy_table/dummy_share, if()s.
Allocating and constructing new handlers.
I suggest the following:

  1. Introduce new handlerton method hton->drop_table().
     By default it'll be

        hton->get_new_handler()
        get_canonical_filename() 
        file->ha_delete_table()

     like now, so all engines will still work. But later we can start
     moving drop table functionality out of the handler. In this commit
     only engines like blackhole will have a dummy drop_table() method.

  2. Here you can do, basically

       hton->drop_table(hton, param->path)

     without checking for discovery, without a new flag
     HTON_AUTOMATIC_DELETE_TABLE. I'm not sure why you check for
     DB_TYPE_HEAP, could you please explain that?
...
+    if (error > 0 && !non_existing_table_error(error))
+      param->error= error;
+    if (error == 0)
+    {
+      param->error= 0;
+      return TRUE;                                // Table was deleted
+    }
+  }
+  return FALSE;
+}
+
+/**
+   @brief
+   Traverse all plugins to delete table when .frm file is missing.
+
+   @return -1  Table was not found in any engine
+   @return 0  Table was found in some engine and delete succeded
+   @return #  Error from first engine that had a table but didn't succeed to
+              delete the table
+   @return HA_ERR_ROW_IS_REFERENCED if foreign key reference is encountered,
+
+*/
+
+int ha_delete_table_force(THD *thd, const char *path, const LEX_CSTRING *db,
+                          const LEX_CSTRING *alias, bool generate_warning)
+{
+  st_force_drop_table_params param;
+  Table_exists_error_handler no_such_table_handler;
+  DBUG_ENTER("ha_delete_table_force");
+
+  param.path=             path;
+  param.db=               db;
+  param.alias=            alias;
+  param.generate_warning= generate_warning;
this is never used, you always invoke ha_delete_table_force() with
generate_warning=0.
...
+  param.error=            -1;                   // Table not found
+
+  thd->push_internal_handler(&no_such_table_handler);
+  if (plugin_foreach(thd, delete_table_force, MYSQL_STORAGE_ENGINE_PLUGIN,
+                     ¶m))
+    param.error= 0;                            // Delete succeded
+  thd->pop_internal_handler();
+  DBUG_RETURN(param.error);
+}
+
+
+/**
   Create a table in the engine: public interface.
diff --git a/sql/handler.h b/sql/handler.h
index f592c635c5d..f5ccdbe1ee4 100644
--- a/sql/handler.h
+++ b/sql/handler.h
@@ -1780,6 +1780,13 @@ handlerton *ha_default_tmp_handlerton(THD *thd);
 */
 #define HTON_TRANSACTIONAL_AND_NON_TRANSACTIONAL (1 << 17)
+/*
+  The engine doesn't keep track of tables, delete_table() is not
+  needed and delete_table() always returns 0 (table deleted). This flag
+  mainly used to skip storage engines in case of ha_delete_table_force()
+*/
+#define HTON_AUTOMATIC_DELETE_TABLE (1 << 18)
+
 class Ha_trx_info;
struct THD_TRANS
diff --git a/sql/sql_table.cc b/sql/sql_table.cc
index 61b1113f680..7c79acef3ea 100644
--- a/sql/sql_table.cc
+++ b/sql/sql_table.cc
@@ -2327,36 +2329,42 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
                   thd->find_temporary_table(table) &&
                   table->mdl_request.ticket != NULL));
+    /* First try to delete temporary tables and temporary sequences */
-    if (table->open_type == OT_BASE_ONLY || !is_temporary_table(table) ||
-        (drop_sequence && table->table->s->table_type != TABLE_TYPE_SEQUENCE))
-      error= 1;
-    else
+    if ((table->open_type != OT_BASE_ONLY && is_temporary_table(table)) &&
unnecessary parentheses
...
+        (!drop_sequence || table->table->s->table_type == TABLE_TYPE_SEQUENCE))
     {
       table_creation_was_logged= table->table->s->table_creation_was_logged;
       if (thd->drop_temporary_table(table->table, &is_trans, true))
       {
+        /*
+          This is a very unlikely scenaro as dropping a temporary table
+          should always work. Would be better if we tried to drop all
+          temporary tables before giving the error.
+        */
         error= 1;
         goto err;
       }
-      error= 0;
       table->table= 0;
+      temporary_table_was_dropped= 1;
     }
-    if ((drop_temporary && if_exists) || !error)
+    if ((drop_temporary && if_exists) || temporary_table_was_dropped)
     {
       /*
         This handles the case of temporary tables. We have the following cases:
-          . "DROP TEMPORARY" was executed and a temporary table was affected
-          (i.e. drop_temporary && !error) or the if_exists was specified (i.e.
-          drop_temporary && if_exists).
-
-          . "DROP" was executed but a temporary table was affected (.i.e
-          !error).
+          - "DROP TEMPORARY" was executed and table was dropped
+            temporary_table_was_dropped == 1
+          - "DROP TEMPORARY IF EXISTS" was specified but no temporary table
+            existed
+            temporary_table_was_dropped == 0
       */
       if (!dont_log_query && table_creation_was_logged)
       {
         /*
+          DROP TEMPORARY succeded. For the moment when we only come
+          here on success (error == 0)
DBUG_ASSERT(error == 0) please
...
+
           If there is an error, we don't know the type of the engine
           at this point. So, we keep it in the trx-cache.
         */
@@ -2387,7 +2395,8 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
         is no need to proceed with the code that tries to drop a regular
         table.
       */
-      if (!error) continue;
+      if (temporary_table_was_dropped)
can temporary_table_was_dropped be false here?
...
+        continue;
     }
     else if (!drop_temporary)
     {
@@ -2402,48 +2411,33 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
       path_length= build_table_filename(path, sizeof(path) - 1, db.str,
                                         alias.str, reg_ext, 0);
     }
+
     DEBUG_SYNC(thd, "rm_table_no_locks_before_delete_table");
     error= 0;
-    if (drop_temporary ||
-        (ha_table_exists(thd, &db, &alias, &table_type, &is_sequence) == 0 &&
+    if (drop_temporary)
+    {
+      /* "DROP TEMPORARY" but a temporary table was not found */
+      error= ENOENT;
+    }
+    else if (((frm_exists= ha_table_exists(thd, &db, &alias, &table_type,
+                                           &is_sequence)) == 0 &&
this is an overkill. ha_table_exists() will do a full table discovery,
you don't need it here, because you'll try to delete anyway.

So, basically you only need dd_frm_type() here.
...
table_type == 0) ||
         (!drop_view && (was_view= (table_type == view_pseudo_hton))) ||
         (drop_sequence && !is_sequence))
     {
       /*
         One of the following cases happened:
-          . "DROP TEMPORARY" but a temporary table was not found.
           . "DROP" but table was not found
           . "DROP TABLE" statement, but it's a view.
           . "DROP SEQUENCE", but it's not a sequence
       */
-      was_table= drop_sequence && table_type;
-      if (if_exists)
-      {
-        char buff[FN_REFLEN];
-        int err= (drop_sequence ? ER_UNKNOWN_SEQUENCES :
-                  ER_BAD_TABLE_ERROR);
-        String tbl_name(buff, sizeof(buff), system_charset_info);
-        tbl_name.length(0);
-        tbl_name.append(&db);
-        tbl_name.append('.');
-        tbl_name.append(&table->table_name);
-        push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
-                            err, ER_THD(thd, err),
-                            tbl_name.c_ptr_safe());
-
-        /*
-          Our job is done here. This statement was added to avoid executing
-          unnecessary code farther below which in some strange corner cases
-          caused the server to crash (see MDEV-17896).
-        */
-        goto log_query;
-      }
-      else
-      {
-        non_tmp_error = (drop_temporary ? non_tmp_error : TRUE);
-        error= 1;
-      }
+      wrong_drop_sequence= drop_sequence && table_type;
+      was_table|= wrong_drop_sequence;
+      local_non_tmp_error= 1;
+      error= -1;
+      if ((!frm_exists && !table_type) ||       // no .frm
+          if_exists)
+        error= ENOENT;
     }
     else
     {
@@ -2509,49 +2507,138 @@ int mysql_rm_table_no_locks(THD *thd, TABLE_LIST *tables, bool if_exists,
           goto err;
         }
       }
-      else
+
+      /*
+        Delete the .frm file if we managed to delete the table from the
+        engine or the table didn't exists in the engine
+      */
+      if (likely(!error) || non_existing_table_error(error))
       {
         /* Delete the table definition file */
         strmov(end,reg_ext);
         if (table_type && table_type != view_pseudo_hton &&
-            table_type->discover_table)
+            (table_type->discover_table || error))
I don't think this new drop table logic needs to have any special
handling of discovery. If the table didn't exist in engine - it's the
normal case now, discovery or not, it's be handled normally.
...
{
           /*
-            Table type is using discovery and may not need a .frm file.
+            Table type is using discovery and may not need a .frm file
+            or the .frm file existed but no table in engine.
             Delete it silently if it exists
           */
-          (void) mysql_file_delete(key_file_frm, path, MYF(0));
+          if (mysql_file_delete(key_file_frm, path,
+                                MYF(MY_WME | MY_IGNORE_ENOENT)))
+            error= my_errno;
         }
         else if (unlikely(mysql_file_delete(key_file_frm, path,
-                                            MYF(MY_WME))))
+                                            !error ? MYF(MY_WME) :
+                                            MYF(MY_WME | MY_IGNORE_ENOENT))))
         {
           frm_delete_error= my_errno;
           DBUG_ASSERT(frm_delete_error);
         }
       }
+      frm_was_deleted= 1;
       if (thd->replication_flags & OPTION_IF_EXISTS)
         log_if_exists= 1;
-      if (likely(!error))
+      if (frm_delete_error)
       {
-        int trigger_drop_error= 0;
+        /*
+          Remember error if unexpected error from dropping the .frm file
+          or we got an error from ha_delete_table()
+        */
+        if (frm_delete_error != ENOENT)
+          error= frm_delete_error;
+        else if (if_exists && ! error)
+          thd->clear_error();
no, please, don't do thd->clear_error().
I've seen and fixed so many bugs because of that. The last one - just an
hour ago. Use push_internal_handler() instead.
...
+      }
+      if (likely(!error) || !frm_delete_error)
+        non_tmp_table_deleted= TRUE;
-      if (likely(!frm_delete_error))
+      if (likely(!error) || non_existing_table_error(error))
       {
+        trigger_drop_executed= 1;
+
+        if (Table_triggers_list::drop_all_triggers(thd, &db,
+                                                   &table->table_name,
+                                                   MYF(MY_WME |
+                                                       MY_IGNORE_ENOENT)))
+          error= error ? error : -1;
+      }
+      local_non_tmp_error|= MY_TEST(error);
+    }
+
+    /*
+      If there was no .frm file and the table is not temporary,
+      scan all engines try to drop the table from there.
+      This is to ensure we don't have any partial table files left.
+
+      We check for trigger_drop_executed to ensure we don't again try
+      to drop triggers when it failed above (after sucecssfully dropping
+      the table).
+    */
+    if (non_existing_table_error(error) && !drop_temporary &&
+        table_type != view_pseudo_hton && !trigger_drop_executed &&
+        !wrong_drop_sequence)
+    {
+      char *end;
+      int ferror= 0;
+
+      /* Remove extension for delete */
+      *(end = path + path_length - reg_ext_length) = '\0';
+      ferror= ha_delete_table_force(thd, path, &db,
+                                    &table->table_name, 0);
+      if (!ferror)
+      {
+        /* Table existed and was deleted */
           non_tmp_table_deleted= TRUE;
-          trigger_drop_error=
-            Table_triggers_list::drop_all_triggers(thd, &db,
-                                                   &table->table_name);
+        local_non_tmp_error= 0;
+        error= 0;
         }
+      if (ferror <= 0)
+      {
+        ferror= 0;                              // Ignore table not found
-        if (unlikely(trigger_drop_error) ||
-            (frm_delete_error && frm_delete_error != ENOENT))
-          error= 1;
-        else if (frm_delete_error && if_exists)
-          thd->clear_error();
+        /* Delete the table definition file */
+        if (!frm_was_deleted)
+        {
+          strmov(end, reg_ext);
+          if (mysql_file_delete(key_file_frm, path,
+                                MYF(MY_WME | MY_IGNORE_ENOENT)))
+            ferror= my_errno;
       }
-      non_tmp_error|= MY_TEST(error);
+        if (Table_triggers_list::drop_all_triggers(thd, &db,
+                                                   &table->table_name,
+                                                   MYF(MY_WME |
+                                                       MY_IGNORE_ENOENT)))
+          ferror= -1;
Why do you need two copies of code to drop triggers?
Why cannot you do it once, on the first drop_all_triggers() place?
...
}
+      if (!error)
+        error= ferror;
+    }
+
+    /*
+      Don't give an error if we are using IF EXISTS for a table that
+      didn't exists
+    */
+
+    if (if_exists && non_existing_table_error(error))
+    {
+      char buff[FN_REFLEN];
+      int err= (drop_sequence ? ER_UNKNOWN_SEQUENCES :
+                ER_BAD_TABLE_ERROR);
+      String tbl_name(buff, sizeof(buff), system_charset_info);
+      tbl_name.length(0);
+      tbl_name.append(&db);
+      tbl_name.append('.');
+      tbl_name.append(&table->table_name);
+      push_warning_printf(thd, Sql_condition::WARN_LEVEL_NOTE,
+                          err, ER_THD(thd, err),
+                          tbl_name.c_ptr_safe());
+      error= 0;
+      local_non_tmp_error= 0;
+      drop_table_not_done= 1;
+    }
+    non_tmp_error|= local_non_tmp_error;
if (error)
     {
diff --git a/storage/blackhole/ha_blackhole.cc b/storage/blackhole/ha_blackhole.cc
index 15548350b20..98589f1d043 100644
--- a/storage/blackhole/ha_blackhole.cc
+++ b/storage/blackhole/ha_blackhole.cc
@@ -399,7 +399,7 @@ static int blackhole_init(void *p)
   blackhole_hton= (handlerton *)p;
   blackhole_hton->db_type= DB_TYPE_BLACKHOLE_DB;
   blackhole_hton->create= blackhole_create_handler;
-  blackhole_hton->flags= HTON_CAN_RECREATE;
+  blackhole_hton->flags= HTON_CAN_RECREATE | HTON_AUTOMATIC_DELETE_TABLE;
mysql_mutex_init(bh_key_mutex_blackhole,
                    &blackhole_mutex, MY_MUTEX_INIT_FAST);
diff --git a/storage/blackhole/ha_blackhole.h b/storage/blackhole/ha_blackhole.h
index 6ee30877b64..646fba6da9f 100644
--- a/storage/blackhole/ha_blackhole.h
+++ b/storage/blackhole/ha_blackhole.h
@@ -95,6 +95,10 @@ class ha_blackhole: public handler
   THR_LOCK_DATA **store_lock(THD *thd,
                              THR_LOCK_DATA **to,
                              enum thr_lock_type lock_type);
+  int delete_table(const char *name)
+  {
+    return 0;
+  }
 private:
   virtual int write_row(const uchar *buf);
   virtual int update_row(const uchar *old_data, const uchar *new_data);
diff --git a/storage/connect/ha_connect.cc b/storage/connect/ha_connect.cc
index 0194b08c792..b1b44085e53 100644
--- a/storage/connect/ha_connect.cc
+++ b/storage/connect/ha_connect.cc
@@ -5192,7 +5192,8 @@ int ha_connect::delete_or_rename_table(const char *name, const char *to)
         } // endif pos
} // endif open_table_def
-
+      else
+        rc= ENOENT;
     free_table_share(share);
   } else              // Temporary file
     ok= true;
diff --git a/storage/connect/mysql-test/connect/r/drop-open-error.result b/storage/connect/mysql-test/connect/r/drop-open-error.result
index f0ad8553d8b..34f58a845dc 100644
--- a/storage/connect/mysql-test/connect/r/drop-open-error.result
+++ b/storage/connect/mysql-test/connect/r/drop-open-error.result
@@ -2,6 +2,8 @@ create table t1 (c varchar(8));
 create table tcon engine=connect table_type=mysql CONNECTION='mysql://root@localhost/test/t1' SRCDEF='select c from t1 where c in ("foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", 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"foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar", "foo", "bar", "qux", "foobar")';
 ERROR HY000: Too long value for 'SRCDEF'
 drop table mdev9949;
+Warnings:
+Warning 1017    Can't find file: './test/mdev9949.dos' (errno: 2 "No such file or directory")
 drop table t1;
 select @@secure_file_priv 'must be NULL';
 must be NULL
diff --git a/storage/federated/ha_federated.cc b/storage/federated/ha_federated.cc
index 00168791d35..b62b74d12bb 100644
--- a/storage/federated/ha_federated.cc
+++ b/storage/federated/ha_federated.cc
@@ -484,7 +484,8 @@ int federated_db_init(void *p)
   federated_hton->commit= federated_commit;
   federated_hton->rollback= federated_rollback;
   federated_hton->create= federated_create_handler;
-  federated_hton->flags= HTON_ALTER_NOT_SUPPORTED | HTON_NO_PARTITION;
+  federated_hton->flags= (HTON_ALTER_NOT_SUPPORTED | HTON_NO_PARTITION |
+                          HTON_AUTOMATIC_DELETE_TABLE);
/*
     Support for transactions disabled until WL#2952 fixes it.
diff --git a/storage/federated/ha_federated.h b/storage/federated/ha_federated.h
index 080d0ebd5f0..2e785f87858 100644
--- a/storage/federated/ha_federated.h
+++ b/storage/federated/ha_federated.h
@@ -244,7 +244,10 @@ class ha_federated: public handler
   void update_auto_increment(void);
   int repair(THD* thd, HA_CHECK_OPT* check_opt);
   int optimize(THD* thd, HA_CHECK_OPT* check_opt);
-
+  int delete_table(const char *name)
+  {
+    return 0;
+  }
   int delete_all_rows(void);
   int truncate();
   int create(const char *name, TABLE *form,
diff --git a/storage/federatedx/ha_federatedx.cc b/storage/federatedx/ha_federatedx.cc
index 6547964cc11..2370473236e 100644
--- a/storage/federatedx/ha_federatedx.cc
+++ b/storage/federatedx/ha_federatedx.cc
@@ -438,7 +438,8 @@ int federatedx_db_init(void *p)
   federatedx_hton->rollback= ha_federatedx::rollback;
   federatedx_hton->discover_table_structure= ha_federatedx::discover_assisted;
   federatedx_hton->create= federatedx_create_handler;
-  federatedx_hton->flags= HTON_ALTER_NOT_SUPPORTED;
+  federatedx_hton->flags= (HTON_ALTER_NOT_SUPPORTED |
+                           HTON_AUTOMATIC_DELETE_TABLE);
   federatedx_hton->create_derived= create_federatedx_derived_handler;
   federatedx_hton->create_select= create_federatedx_select_handler;
diff --git a/storage/federatedx/ha_federatedx.h b/storage/federatedx/ha_federatedx.h
index a62456e1c33..67fe5f8cc22 100644
--- a/storage/federatedx/ha_federatedx.h
+++ b/storage/federatedx/ha_federatedx.h
@@ -431,7 +431,10 @@ class ha_federatedx: public handler
   void update_auto_increment(void);
   int repair(THD* thd, HA_CHECK_OPT* check_opt);
   int optimize(THD* thd, HA_CHECK_OPT* check_opt);
-
+  int delete_table(const char *name)
+  {
+    return 0;
+  }
   int delete_all_rows(void);
   int create(const char *name, TABLE *form,
              HA_CREATE_INFO *create_info);                      //required
diff --git a/storage/innobase/handler/ha_innodb.cc b/storage/innobase/handler/ha_innodb.cc
index 6940f8ff3bd..97cfdb01d9f 100644
--- a/storage/innobase/handler/ha_innodb.cc
+++ b/storage/innobase/handler/ha_innodb.cc
@@ -13347,5 +13347,18 @@ ha_innobase::discard_or_import_tablespace(
 }
/**
+   @return 1 if frm file exists
+   @return 0 if it doesn't exists
+*/
+
+static bool frm_file_exists(const char *path)
+{
+  char buff[FN_REFLEN];
+  strxnmov(buff, FN_REFLEN, path, reg_ext, NullS);
+  return !access(buff, F_OK);
+}
+
+
+/**
 Drops a table from an InnoDB database. Before calling this function,
 MySQL calls innobase_commit to commit the transaction of the current user.
@@ -13446,7 +13459,9 @@ inline int ha_innobase::delete_table(const char* name, enum_sql_command sqlcom)
                 }
         }
-        if (err == DB_TABLE_NOT_FOUND) {
+        if (err == DB_TABLE_NOT_FOUND &&
+            frm_file_exists(name))
+        {
                 /* Test to drop all tables which matches db/tablename + '#'.
                 Only partitions can have '#' as non-first character in
                 the table name!
diff --git a/storage/mroonga/mrn_table.cpp b/storage/mroonga/mrn_table.cpp
index b1b2db6161b..037a6a59487 100644
--- a/storage/mroonga/mrn_table.cpp
+++ b/storage/mroonga/mrn_table.cpp
@@ -1080,6 +1080,7 @@ TABLE_SHARE *mrn_create_tmp_table_share(TABLE_LIST *table_list, const char *path
   if (open_table_def(thd, share, GTS_TABLE))
   {
     *error = ER_CANT_OPEN_FILE;
+    mrn_free_tmp_table_share(share);
     DBUG_RETURN(NULL);
   }
   DBUG_RETURN(share);
diff --git a/storage/myisam/mi_delete_table.c b/storage/myisam/mi_delete_table.c
index 7990c3e8a80..d318b44720a 100644
--- a/storage/myisam/mi_delete_table.c
+++ b/storage/myisam/mi_delete_table.c
@@ -28,19 +28,23 @@
int mi_delete_table(const char *name)
 {
+  int error= 0;
   DBUG_ENTER("mi_delete_table");
#ifdef EXTRA_DEBUG
   check_table_is_closed(name,"delete");
 #endif
-  if (mysql_file_delete_with_symlink(mi_key_file_kfile, name, MI_NAME_IEXT, MYF(MY_WME)) ||
-      mysql_file_delete_with_symlink(mi_key_file_dfile, name, MI_NAME_DEXT, MYF(MY_WME)))
-    DBUG_RETURN(my_errno);
+  if (mysql_file_delete_with_symlink(mi_key_file_kfile, name, MI_NAME_IEXT,
+                                     MYF(MY_WME)))
+    error= my_errno;
+  if (mysql_file_delete_with_symlink(mi_key_file_dfile, name, MI_NAME_DEXT,
+                                     MYF(MY_WME)))
+    error= my_errno;
// optionally present:
   mysql_file_delete_with_symlink(mi_key_file_dfile, name, ".OLD", MYF(0));
   mysql_file_delete_with_symlink(mi_key_file_dfile, name, ".TMD", MYF(0));
-  DBUG_RETURN(0);
+  DBUG_RETURN(error);
 }
diff --git a/storage/perfschema/ha_perfschema.cc b/storage/perfschema/ha_perfschema.cc
index 33d4c854c8b..c4c59d109f5 100644
--- a/storage/perfschema/ha_perfschema.cc
+++ b/storage/perfschema/ha_perfschema.cc
@@ -95,10 +95,11 @@ static int pfs_init_func(void *p)
pfs_hton->create= pfs_create_handler;
   pfs_hton->show_status= pfs_show_status;
-  pfs_hton->flags= HTON_ALTER_NOT_SUPPORTED |
+  pfs_hton->flags= (HTON_ALTER_NOT_SUPPORTED |
     HTON_TEMPORARY_NOT_SUPPORTED |
     HTON_NO_PARTITION |
-    HTON_NO_BINLOG_ROW_OPT;
+                    HTON_NO_BINLOG_ROW_OPT |
+                    HTON_AUTOMATIC_DELETE_TABLE);
/*
     As long as the server implementation keeps using legacy_db_type,
diff --git a/storage/sequence/sequence.cc b/storage/sequence/sequence.cc
index 8684a5c60b9..31522b8f3b7 100644
--- a/storage/sequence/sequence.cc
+++ b/storage/sequence/sequence.cc
@@ -69,10 +69,15 @@ class ha_seq: public handler
/* open/close/locking */
   int create(const char *name, TABLE *table_arg,
-             HA_CREATE_INFO *create_info) { return HA_ERR_WRONG_COMMAND; }
+             HA_CREATE_INFO *create_info)
+  { return HA_ERR_WRONG_COMMAND; }
int open(const char *name, int mode, uint test_if_locked);
   int close(void);
+  int delete_table(const char *name)
+  {
+    return 0;
+  }
   THR_LOCK_DATA **store_lock(THD *, THR_LOCK_DATA **, enum thr_lock_type);
/* table scan */
@@ -503,6 +508,7 @@ static int init(void *p)
   hton->savepoint_set= hton->savepoint_rollback= hton->savepoint_release=
     dummy_savepoint;
   hton->create_group_by= create_group_by_handler;
+  hton->flags= HTON_AUTOMATIC_DELETE_TABLE;
   return 0;
 }
@@ -526,4 +532,3 @@ maria_declare_plugin(sequence)
   MariaDB_PLUGIN_MATURITY_STABLE
 }
 maria_declare_plugin_end;
-
diff --git a/storage/sphinx/ha_sphinx.cc b/storage/sphinx/ha_sphinx.cc
index 8403c767796..d60a4d229e6 100644
--- a/storage/sphinx/ha_sphinx.cc
+++ b/storage/sphinx/ha_sphinx.cc
@@ -696,7 +696,7 @@ handlerton sphinx_hton =
         NULL,   // create_cursor_read_view
         NULL,   // set_cursor_read_view
         NULL,   // close_cursor_read_view
-        HTON_CAN_RECREATE
+        HTON_CAN_RECREATE | HTON_AUTOMATIC_DELETE_TABLE
 };
 #else
 static handlerton * sphinx_hton_ptr = NULL;
@@ -749,7 +749,7 @@ static int sphinx_init_func ( void * p )
                 hton->close_connection = sphinx_close_connection;
                 hton->show_status = sphinx_show_status;
                 hton->panic = sphinx_panic;
-                hton->flags = HTON_CAN_RECREATE;
+                hton->flags = HTON_CAN_RECREATE | HTON_AUTOMATIC_DELETE_TABLE;
                 #endif
         }
         SPH_RET(0);
diff --git a/storage/spider/spd_table.cc b/storage/spider/spd_table.cc
index 1607dd07902..583bfebbed6 100644
--- a/storage/spider/spd_table.cc
+++ b/storage/spider/spd_table.cc
@@ -7249,7 +7249,7 @@ int spider_db_init(
   DBUG_ENTER("spider_db_init");
   spider_hton_ptr = spider_hton;
-  spider_hton->flags = HTON_NO_FLAGS;
+  spider_hton->flags = HTON_NO_FLAGS | HTON_AUTOMATIC_DELETE_TABLE;
 #ifdef HTON_CAN_READ_CONNECT_STRING_IN_PARTITION
   spider_hton->flags |= HTON_CAN_READ_CONNECT_STRING_IN_PARTITION;
 #endif
Regards,
Sergei
VP of MariaDB Server Engineering
and security@mariadb.org

    

Re: [Maria-developers] 250bc3b6d74: Ensure that table is truly dropped when using DROP TABLE

Sergei Golubchik