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

[Nickolay Ihalainen]

With innodb_large_prefix=1 blackhole storage engine is incompatible with innodb table definitions,
thus adding new indexes breaking slave.

mysqltest: At line 3: query 'ALTER TABLE t ADD KEY (c)' failed: 1071: Specified key was too long; max key length is 1000 bytes

ihanick@dev percona-server]$ git diff
diff --git a/storage/blackhole/ha_blackhole.h b/storage/blackhole/ha_blackhole.h
index df10e7d..e265ccf 100644
--- a/storage/blackhole/ha_blackhole.h
+++ b/storage/blackhole/ha_blackhole.h
@@ -66,7 +66,7 @@ public:
   /* The following defines can be increased if necessary */
 #define BLACKHOLE_MAX_KEY 64 /* Max allowed keys */
 #define BLACKHOLE_MAX_KEY_SEG 16 /* Max segments for key */
-#define BLACKHOLE_MAX_KEY_LENGTH 1000
+#define BLACKHOLE_MAX_KEY_LENGTH 10000
   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; }
[ihanick@dev percona-server]$ cat mysql-test/t/blackhole_max_key_len.test
--source include/have_blackhole.inc
CREATE TABLE t(c varchar(255)) DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci ENGINE=blackhole;
ALTER TABLE t ADD KEY (c);
DROP TABLE t;[ihanick@dev percona-server]$ cat mysql-test/r/blackhole_max_key_len.result
CREATE TABLE t(c varchar(255)) DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci ENGINE=blackhole;
ALTER TABLE t ADD KEY (c);
DROP TABLE t;
ihanick@dev percona-server]$ cat mysql-test/r/blackhole_max_key_len.result
CREATE TABLE t(c varchar(255)) DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_unicode_ci ENGINE=blackhole;
ALTER TABLE t ADD KEY (c);
DROP TABLE t;

[Vlad Lesin (vlad-lesin)]

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 implemented for blackhole now.

https://github.com/vlad-lesin/percona-server/tree/blackhole-max-key-length-5.5-gca
https://github.com/vlad-lesin/percona-server/tree/blackhole-max-key-length-5.6-gca
https://github.com/vlad-lesin/percona-server/tree/blackhole-max-key-length-5.7-gca

[Vlad Lesin (vlad-lesin)]

https://github.com/percona/percona-server/pull/1999
https://github.com/percona/percona-server/pull/2000
https://github.com/percona/percona-server/pull/2001

[Vlad Lesin (vlad-lesin)]

As http://bugs.mysql.com/bug.php?id=53588 was not opened at the moment of contribution, the new bug report is created https://bugs.mysql.com/bug.php?id=89265 co contribute.

[Shahriyar Rzayev (rzayev-sehriyar)]

Percona now uses JIRA for bug reports so this bug report is migrated to: https://jira.percona.com/browse/PS-1126