MDEV-24017: Blackhole : Specified key was too long; max key length is 1000 bytes

The maximum innodb key length is 3500 what is hardcoded in
ha_innobase::max_supported_key_length()). The maximum number of innodb indexes
is configured with MAX_INDEXES macro (see also MAX_KEY definition).

The same is currently implemented for blackhole storage engine.

Cherry picked from percona-server 0d90d81c3c507a6b1476246a405504f6e4ef9d4d
Original lp bug 1733049

Reviewed-by: daniel@mariadb.org

mysql-test/r/blackhole.result

@@ -24,3 +24,9 @@ SELECT 0 FROM t1 FORCE INDEX FOR GROUP BY(a) WHERE a = 0 OR b = 0 AND c = 0;
 0
 DROP TABLE t1;
 End of 5.6 tests
+CREATE TABLE `t` (
+`a` varchar(3000) NOT NULL default '',
+PRIMARY KEY  (`a`)
+) ENGINE=BLACKHOLE;
+DROP TABLE `t`;
+End of 10.1 tests

mysql-test/t/blackhole.test

@@ -38,3 +38,19 @@ SELECT 0 FROM t1 FORCE INDEX FOR GROUP BY(a) WHERE a = 0 OR b = 0 AND c = 0;
 DROP TABLE t1;
 
 --echo End of 5.6 tests
+
+#
+# MDEV-24017 / bug 53588 test case.
+#
+# Create long enough index (between 1000 and 3500). 1000 is the old value,
+# 3500 is innodb value (see ha_innobase::max_supported_key_length()). Without
+# the fix the test will fail with "Specified key was too long" error.
+#
+CREATE TABLE `t` (
+  `a` varchar(3000) NOT NULL default '',
+  PRIMARY KEY  (`a`)
+) ENGINE=BLACKHOLE;
+
+DROP TABLE `t`;
+
+--echo End of 10.1 tests

storage/blackhole/ha_blackhole.h

@@ -20,6 +20,7 @@
 #include "thr_lock.h"                           /* THR_LOCK */
 #include "handler.h"                            /* handler */
 #include "table.h"                              /* TABLE_SHARE */
+#include "sql_const.h"                          /* MAX_KEY */
 
 /*
   Shared structure for correct LOCK operation
@@ -65,9 +66,9 @@ class ha_blackhole: public handler
             HA_READ_ORDER | HA_KEYREAD_ONLY);
   }
   /* The following defines can be increased if necessary */
-#define BLACKHOLE_MAX_KEY	64		/* Max allowed keys */
+#define BLACKHOLE_MAX_KEY	MAX_KEY		/* Max allowed keys */
 #define BLACKHOLE_MAX_KEY_SEG	16		/* Max segments for key */
-#define BLACKHOLE_MAX_KEY_LENGTH 1000
+#define BLACKHOLE_MAX_KEY_LENGTH	3500		/* Like in InnoDB */
   uint max_supported_keys()          const { return BLACKHOLE_MAX_KEY; }
   uint max_supported_key_length()    const { return BLACKHOLE_MAX_KEY_LENGTH; }
   uint max_supported_key_part_length() const { return BLACKHOLE_MAX_KEY_LENGTH; }