From: Mattias Jonsson
Date: January 26 2012 9:31am
Subject: bzr push into mysql-trunk branch (mattias.jonsson:3791 to 3792) Bug#13511529
List-Archive: http://lists.mysql.com/commits/142570
X-Bug: 13511529
Message-Id: <201201260931.q0Q9V00I029150@acsmt358.oracle.com>
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 3792 Mattias Jonsson	2012-01-26
      Bug#13511529: EXAMPLE ENGINE DOES NOT SUPPORT RND_INIT(),
      BUT SUPPORTS RND_NEXT()
      
      After checking return value from rnd_init() the example engine
      failed even on selects, where it previously succeeded.
      
      Problem was that ha_example::rnd_init always returned
      HA_ERR_WRONG_COMMAND, so that it would never try
      rnd_next.
      
      Fixed by always return 0 in rnd_init, so it would try
      rnd_next.
      
      Also added a couple of tests to show the lack of features in
      the example engine.
      
      Updated test after review.

    modified:
      mysql-test/r/plugin.result
      mysql-test/t/plugin.test
      storage/example/ha_example.cc
 3791 Tor Didriksen	2012-01-26 [merge]
      merge 5.5 => trunk

    modified:
      mysql-test/r/mysqld--help-win.result
=== modified file 'mysql-test/r/plugin.result'
--- a/mysql-test/r/plugin.result	revid:tor.didriksen@stripped
+++ b/mysql-test/r/plugin.result	revid:mattias.jonsson@stripped
@@ -9,9 +9,31 @@ ERROR HY000: Function 'EXAMPLE' already 
 UNINSTALL PLUGIN example;
 INSTALL PLUGIN example SONAME 'ha_example.so';
 CREATE TABLE t1(a int) ENGINE=EXAMPLE;
+SHOW CREATE TABLE t1;
+Table	Create Table
+t1	CREATE TABLE `t1` (
+  `a` int(11) DEFAULT NULL
+) ENGINE=EXAMPLE DEFAULT CHARSET=latin1
+# Let's do some advanced ops with the example engine :)
+INSERT INTO t1 VALUES (0);
+# Only supports table scans (and does always return zero rows :)
 SELECT * FROM t1;
+a
+SELECT * FROM t1 WHERE a = 0;
+a
+# Since there are no rows found, it will never do update_row.
+UPDATE t1 SET a = 1 WHERE a = 0;
+# Since there are no rows found, it will never do delete_row.
+DELETE FROM t1 WHERE a = 0;
+# No support for SQL HANDLER statement
+HANDLER t1 OPEN;
 ERROR HY000: Table storage engine for 't1' doesn't have this option
 DROP TABLE t1;
+# Example engine does not support indexes
+CREATE TABLE t1 (a int PRIMARY KEY) ENGINE=EXAMPLE;
+ERROR 42000: Too many key parts specified; max 0 parts allowed
+CREATE TABLE t1 (a int, KEY (a)) ENGINE=EXAMPLE;
+ERROR 42000: Too many key parts specified; max 0 parts allowed
 set global example_ulong_var=500;
 set global example_enum_var= e1;
 show status like 'example%';

=== modified file 'mysql-test/t/plugin.test'
--- a/mysql-test/t/plugin.test	revid:tor.didriksen@stripped
+++ b/mysql-test/t/plugin.test	revid:mattias.jonsson@stripped
@@ -17,11 +17,33 @@ eval INSTALL PLUGIN example SONAME '$EXA
 
 CREATE TABLE t1(a int) ENGINE=EXAMPLE;
 
---error ER_ILLEGAL_HA
+SHOW CREATE TABLE t1;
+
+--echo # Let's do some advanced ops with the example engine :)
+INSERT INTO t1 VALUES (0);
+
+--echo # Only supports table scans (and does always return zero rows :)
 SELECT * FROM t1;
+SELECT * FROM t1 WHERE a = 0;
+
+--echo # Since there are no rows found, it will never do update_row.
+UPDATE t1 SET a = 1 WHERE a = 0;
+
+--echo # Since there are no rows found, it will never do delete_row.
+DELETE FROM t1 WHERE a = 0;
+
+--echo # No support for SQL HANDLER statement
+--error ER_ILLEGAL_HA
+HANDLER t1 OPEN;
 
 DROP TABLE t1;
 
+--echo # Example engine does not support indexes
+--error ER_TOO_MANY_KEY_PARTS
+CREATE TABLE t1 (a int PRIMARY KEY) ENGINE=EXAMPLE;
+--error ER_TOO_MANY_KEY_PARTS
+CREATE TABLE t1 (a int, KEY (a)) ENGINE=EXAMPLE;
+
 # a couple of tests for variables
 set global example_ulong_var=500;
 set global example_enum_var= e1;

=== modified file 'storage/example/ha_example.cc'
--- a/storage/example/ha_example.cc	revid:tor.didriksen@stripped
+++ b/storage/example/ha_example.cc	revid:mattias.jonsson@stripped
@@ -554,7 +554,7 @@ int ha_example::index_last(uchar *buf)
 int ha_example::rnd_init(bool scan)
 {
   DBUG_ENTER("ha_example::rnd_init");
-  DBUG_RETURN(HA_ERR_WRONG_COMMAND);
+  DBUG_RETURN(0);
 }
 
 int ha_example::rnd_end()

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