MDEV-4280: Assertion `empty_size == empty_size_on_page' failure in ma_blockrec.c or ER_NOT_KEYFILE on query with DISTINCT and GROUP BY

This could happen when using Aria for internal temporary files (default case) and using DISTINCT.
_ma_scan_restore_block_record() didn't work correctly if there was rows inserted, updated or deleted on the handler
between calls to _ma_scan_remember_block_record() and _ma_scan_restore_block_record().
The effect was that some DISTINCT queries that used remove_dup_with_compare() could fail.

.bzrignore:
  Ignore sql_yacc.hh
mysql-test/suite/maria/r/distinct.result:
  Test case for MDEV-4280
mysql-test/suite/maria/t/distinct.test:
  Test case for MDEV-4280
mysql-test/t/mysql.test:
  Fixed test suite (we could get error -1 in some cases)
sql/sql_select.cc:
  Break loop if restart_rnd_next() gives an error
storage/maria/ha_maria.cc:
  scan_restore_pos() can return disk fault error.
storage/maria/ma_blockrec.c:
  _ma_scan_remember_block_record() did incorrectly update scan.dir instead of scan_save.dir .
  _ma_scan_restore_block_record() didn't work correctly if there was rows inserted,updated or deleted on the handler
  between calls to _ma_scan_remember_block_record() and _ma_scan_restore_block_record().
  Fixed by adding counters for row changes and reading the current scan page if changes had been made.
storage/maria/ma_blockrec.h:
  scan_restore_pos() can return disk fault error.
storage/maria/ma_delete.c:
  Increment row_changes
storage/maria/ma_scan.c:
  scan_restore_pos() can return disk fault error.
storage/maria/ma_update.c:
  Increment row_changes
storage/maria/ma_write.c:
  Increment row_changes
storage/maria/maria_def.h:
  scan_restore_pos() can return disk fault error.

2 files changed, 50 insertions, 0 deletions

diff --git a/mysql-test/suite/maria/r/distinct.result b/mysql-test/suite/maria/r/distinct.result
new file mode 100644
index 00000000000..04d5e3d6a2c
--- /dev/null
+++ b/mysql-test/suite/maria/r/distinct.result
@@ -0,0 +1,25 @@
+DROP TABLE IF EXISTS t1;
+CREATE TABLE t1 (a INT, b INT) ENGINE=Aria;
+INSERT t1 VALUES (3,2004),(2,2006),(1,2007),(3,2008),(2,2005),(2,2001);
+SELECT GROUP_CONCAT(a) FROM t1 GROUP BY b;
+GROUP_CONCAT(a)
+2
+3
+2
+2
+1
+3
+SELECT DISTINCT GROUP_CONCAT(a) FROM t1 GROUP BY b;
+GROUP_CONCAT(a)
+2
+3
+1
+DROP TABLE t1;
+CREATE TABLE t1 (a INT, b VARCHAR(1)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (7,'q'),(2,NULL),(7,'g'),(6,'x');
+SELECT DISTINCT MAX( a ) FROM t1 GROUP BY b ORDER BY DES_DECRYPT( b );
+MAX( a )
+2
+7
+6
+DROP TABLE t1;
diff --git a/mysql-test/suite/maria/t/distinct.test b/mysql-test/suite/maria/t/distinct.test
new file mode 100644
index 00000000000..b30d97b8383
--- /dev/null
+++ b/mysql-test/suite/maria/t/distinct.test
@@ -0,0 +1,25 @@
+#
+# MDEV-4280:
+# Assertion `empty_size == empty_size_on_page' failure in ma_blockrec.c or
+# ER_NOT_KEYFILE on query with DISTINCT and GROUP BY
+#
+# This issue was a bug in how we delete row during duplicate removal when
+# we use Aria for internal temporary table.
+# 
+
+-- source include/have_maria.inc
+
+--disable_warnings
+DROP TABLE IF EXISTS t1;
+--enable_warnings
+
+CREATE TABLE t1 (a INT, b INT) ENGINE=Aria;
+INSERT t1 VALUES (3,2004),(2,2006),(1,2007),(3,2008),(2,2005),(2,2001);
+SELECT GROUP_CONCAT(a) FROM t1 GROUP BY b;
+SELECT DISTINCT GROUP_CONCAT(a) FROM t1 GROUP BY b;
+DROP TABLE t1;
+
+CREATE TABLE t1 (a INT, b VARCHAR(1)) ENGINE=MyISAM;
+INSERT INTO t1 VALUES (7,'q'),(2,NULL),(7,'g'),(6,'x');
+SELECT DISTINCT MAX( a ) FROM t1 GROUP BY b ORDER BY DES_DECRYPT( b );
+DROP TABLE t1;