MDEV-19055 Failures with temporary tables and Aria

There was two separate problems:
- Aria pagecache didn't properly handle re-reading of blocks
  that have given errors before (this triggered an assert)
- temporary tables that where opened several times where
  not properly closed in ALTER, REPAIR or OPTIMIZE table

Other things
- Added a couple of asserts that will make it easier to
  find problems like this in the future.

mysql-test/suite/maria/alter.result

@@ -47,3 +47,46 @@ t1	CREATE TABLE `t1` (
 ) ENGINE=Aria DEFAULT CHARSET=latin1 PAGE_CHECKSUM=1 TRANSACTIONAL=1
 CREATE TABLE t2 SELECT * FROM t1;
 DROP TABLE t1, t2;
+#
+# MDEV-19055 Assertion `(_my_thread_var())->thr_errno != 0' failed in pagecache_read
+#
+CREATE OR REPLACE TABLE t1 (x INT) ENGINE=Aria;
+CREATE TEMPORARY TABLE t2 (a TIME) ENGINE=Aria;
+ALTER TABLE t2 ADD b DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP;
+ALTER TABLE t2 ADD CHECK (b = 4);
+INSERT IGNORE INTO t2 () VALUES (),(),(),();
+ALTER IGNORE TABLE t2 ADD c INT;
+SELECT count(a),sum(a) FROM t2;
+count(a)	sum(a)
+0	NULL
+DELETE FROM t2 ORDER BY c LIMIT 1;
+INSERT IGNORE INTO t2 SELECT * FROM t2;
+OPTIMIZE TABLE t2;
+Table	Op	Msg_type	Msg_text
+test.t2	optimize	status	OK
+SELECT count(a),sum(a) FROM t2;
+count(a)	sum(a)
+0	NULL
+INSERT IGNORE INTO t2 SELECT * FROM t2;
+SET SQL_MODE= 'STRICT_ALL_TABLES';
+SELECT count(a),sum(a) FROM t2;
+count(a)	sum(a)
+0	NULL
+ALTER TABLE t2 CHANGE IF EXISTS d c INT;
+ERROR 22007: Incorrect datetime value: '4'
+SELECT count(a),sum(a) FROM t2;
+count(a)	sum(a)
+0	NULL
+ALTER IGNORE TABLE t2 ADD IF NOT EXISTS e BIT;
+ALTER TABLE t1 MODIFY IF EXISTS xx INT;
+INSERT IGNORE INTO t2 () VALUES (),(),(),();
+SELECT count(a),sum(a) FROM t2;
+count(a)	sum(a)
+0	NULL
+check table t1;
+Table	Op	Msg_type	Msg_text
+test.t1	check	status	OK
+check table t2;
+Table	Op	Msg_type	Msg_text
+test.t2	check	status	OK
+DROP TABLE t1,t2;

mysql-test/suite/maria/alter.test

@@ -42,3 +42,38 @@ ALTER TABLE t1 ORDER BY unknown_column;
 SHOW CREATE TABLE t1;
 CREATE TABLE t2 SELECT * FROM t1;
 DROP TABLE t1, t2;
+
+--echo #
+--echo # MDEV-19055 Assertion `(_my_thread_var())->thr_errno != 0' failed in pagecache_read
+--echo #
+
+--disable_warnings
+CREATE OR REPLACE TABLE t1 (x INT) ENGINE=Aria;
+CREATE TEMPORARY TABLE t2 (a TIME) ENGINE=Aria;
+ALTER TABLE t2 ADD b DATETIME NOT NULL DEFAULT CURRENT_TIMESTAMP;
+ALTER TABLE t2 ADD CHECK (b = 4);
+INSERT IGNORE INTO t2 () VALUES (),(),(),();
+ALTER IGNORE TABLE t2 ADD c INT;
+SELECT count(a),sum(a) FROM t2;
+DELETE FROM t2 ORDER BY c LIMIT 1;
+INSERT IGNORE INTO t2 SELECT * FROM t2;
+OPTIMIZE TABLE t2;
+SELECT count(a),sum(a) FROM t2;
+INSERT IGNORE INTO t2 SELECT * FROM t2;
+SET SQL_MODE= 'STRICT_ALL_TABLES';
+SELECT count(a),sum(a) FROM t2;
+--error ER_TRUNCATED_WRONG_VALUE
+ALTER TABLE t2 CHANGE IF EXISTS d c INT;
+SELECT count(a),sum(a) FROM t2;
+ALTER IGNORE TABLE t2 ADD IF NOT EXISTS e BIT;
+ALTER TABLE t1 MODIFY IF EXISTS xx INT;
+INSERT IGNORE INTO t2 () VALUES (),(),(),();
+SELECT count(a),sum(a) FROM t2;
+--enable_warnings
+check table t1;
+check table t2;
+DROP TABLE t1,t2;
+
+#
+# End of 10.2 tests
+#

mysys/my_pread.c

@@ -68,6 +68,8 @@ size_t my_pread(File Filedes, uchar *Buffer, size_t Count, my_off_t offset,
 
     if (readbytes != Count)
     {
+      /* We should never read with wrong file descriptor! */
+      DBUG_ASSERT(my_errno != 9);
       my_errno= errno;
       if (errno == 0 || (readbytes != (size_t) -1 &&
                          (MyFlags & (MY_NABP | MY_FNABP))))

sql/sql_admin.cc

@@ -697,19 +697,23 @@ static bool mysql_admin_table(THD* thd, TABLE_LIST* tables,
       MDL_SHARED_NO_READ_WRITE lock (MDL_SHARED_WRITE cannot be upgraded)
       by *not* having HA_CONCURRENT_OPTIMIZE table_flag.
     */
-    if (lock_type == TL_WRITE && !table->table->s->tmp_table &&
-                        table->mdl_request.type > MDL_SHARED_WRITE)
+    if (lock_type == TL_WRITE && table->mdl_request.type > MDL_SHARED_WRITE)
     {
-      if (wait_while_table_is_used(thd, table->table, HA_EXTRA_NOT_USED))
-        goto err;
-      DEBUG_SYNC(thd, "after_admin_flush");
-      /* Flush entries in the query cache involving this table. */
-      query_cache_invalidate3(thd, table->table, 0);
-      /*
-        XXX: hack: switch off open_for_modify to skip the
-        flush that is made later in the execution flow. 
-      */
-      open_for_modify= 0;
+      if (table->table->s->tmp_table)
+        thd->close_unused_temporary_table_instances(tables);
+      else
+      {
+        if (wait_while_table_is_used(thd, table->table, HA_EXTRA_NOT_USED))
+          goto err;
+        DEBUG_SYNC(thd, "after_admin_flush");
+        /* Flush entries in the query cache involving this table. */
+        query_cache_invalidate3(thd, table->table, 0);
+        /*
+          XXX: hack: switch off open_for_modify to skip the
+          flush that is made later in the execution flow.
+        */
+        open_for_modify= 0;
+      }
     }
 
     if (table->table->s->crashed && operator_func == &handler::ha_check)

sql/sql_table.cc

@@ -9536,6 +9536,8 @@ do_continue:;
 
     DEBUG_SYNC(thd, "alter_table_copy_after_lock_upgrade");
   }
+  else
+    thd->close_unused_temporary_table_instances(table_list);
 
   // It's now safe to take the table level lock.
   if (lock_tables(thd, table_list, alter_ctx.tables_opened, 0))

storage/maria/ma_blockrec.c

@@ -5244,6 +5244,8 @@ my_bool _ma_scan_init_block_record(MARIA_HA *info)
 {
   MARIA_SHARE *share= info->s;
   DBUG_ENTER("_ma_scan_init_block_record");
+  DBUG_ASSERT(info->dfile.file == share->bitmap.file.file);
+
   /*
     bitmap_buff may already be allocated if this is the second call to
     rnd_init() without a rnd_end() in between, see sql/handler.h

storage/maria/ma_pagecache.c

@@ -3464,8 +3464,6 @@ restart:
         pagecache_pthread_mutex_lock(&pagecache->cache_lock);
 #endif
       }
-      if (status & PCBLOCK_ERROR)
-        my_errno= block->error;
     }
 
     remove_reader(block);
@@ -3497,6 +3495,7 @@ restart:
 
     if (status & PCBLOCK_ERROR)
     {
+      my_errno= block->error;
       DBUG_ASSERT(my_errno != 0);
       DBUG_PRINT("error", ("Got error %d when doing page read", my_errno));
       DBUG_RETURN((uchar *) 0);