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Bug#11853126 RE-ENABLE CONCURRENT READS WHILE CREATING

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SECONDARY INDEX IN INNODB

The patches for Bug#11751388 and Bug#11784056 enabled concurrent
reads while creating secondary indexes in InnoDB. However, they
introduced a regression. This regression occured if ALTER TABLE
failed after the index had been added, for example during the
lock upgrade needed to update .FRM. If this happened, InnoDB
and the server got out of sync with regards to which indexes
actually existed. Therefore the patch for Bug#11815600 again
disabled concurrent reads.

This patch re-enables concurrent reads. The original regression
is fixed by splitting the ADD INDEX operation into two parts.
First the new index is created but not made active. This is
done while concurrent reads are allowed. The second part of
the operation makes the index active (or reverts the change).
This is done after lock upgrade, which prevents the original
regression.

In order to implement this change, the patch changes the storage
API for in-place index creation. handler::add_index() is split
into two functions, handler_add_index() and
handler::final_add_index(). The former for creating indexes without
making them visible and the latter for commiting (i.e. making
visible) new indexes or reverting the changes.

Large parts of this patch were written by Marko Mäkelä.

Test case added to innodb_mysql_lock.test.
This commit is contained in:
Jon Olav Hauglid
2011-06-01 10:06:55 +02:00
parent bd708b4240
commit f21fd6e40f
11 changed files with 578 additions and 235 deletions
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74
mysql-test/r/innodb_mysql_sync.result
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@ -94,6 +94,74 @@ SET DEBUG_SYNC= 'RESET';
# Bug#42230 during add index, cannot do queries on storage engines
# that implement add_index
#
#
# DISABLED due to Bug#11815600
#
DROP DATABASE IF EXISTS db1;
DROP TABLE IF EXISTS t1;
# Test 1: Secondary index, should not block reads (original test case).
# Connection default
CREATE DATABASE db1;
CREATE TABLE db1.t1(id INT NOT NULL AUTO_INCREMENT PRIMARY KEY, value INT) engine=innodb;
INSERT INTO db1.t1(value) VALUES (1), (2);
SET DEBUG_SYNC= "alter_table_manage_keys SIGNAL manage WAIT_FOR query";
# Sending:
ALTER TABLE db1.t1 ADD INDEX(value);
# Connection con1
SET DEBUG_SYNC= "now WAIT_FOR manage";
USE db1;
SELECT * FROM t1;
id value
1 1
2 2
SET DEBUG_SYNC= "now SIGNAL query";
# Connection default
# Reaping: ALTER TABLE db1.t1 ADD INDEX(value)
DROP DATABASE db1;
# Test 2: Primary index (implicit), should block reads.
CREATE TABLE t1(a INT NOT NULL, b INT NOT NULL) engine=innodb;
SET DEBUG_SYNC= "alter_table_manage_keys SIGNAL manage WAIT_FOR query";
# Sending:
ALTER TABLE t1 ADD UNIQUE INDEX(a);
# Connection con1
SET DEBUG_SYNC= "now WAIT_FOR manage";
USE test;
# Sending:
SELECT * FROM t1;
# Connection con2
# Waiting for SELECT to be blocked by the metadata lock on t1
SET DEBUG_SYNC= "now SIGNAL query";
# Connection default
# Reaping: ALTER TABLE t1 ADD UNIQUE INDEX(a)
# Connection con1
# Reaping: SELECT * FROM t1
a b
# Test 3: Primary index (explicit), should block reads.
# Connection default
ALTER TABLE t1 DROP INDEX a;
SET DEBUG_SYNC= "alter_table_manage_keys SIGNAL manage WAIT_FOR query";
# Sending:
ALTER TABLE t1 ADD PRIMARY KEY (a);
# Connection con1
SET DEBUG_SYNC= "now WAIT_FOR manage";
# Sending:
SELECT * FROM t1;
# Connection con2
# Waiting for SELECT to be blocked by the metadata lock on t1
SET DEBUG_SYNC= "now SIGNAL query";
# Connection default
# Reaping: ALTER TABLE t1 ADD PRIMARY KEY (a)
# Connection con1
# Reaping: SELECT * FROM t1
a b
# Test 4: Secondary unique index, should not block reads.
# Connection default
SET DEBUG_SYNC= "alter_table_manage_keys SIGNAL manage WAIT_FOR query";
# Sending:
ALTER TABLE t1 ADD UNIQUE (b);
# Connection con1
SET DEBUG_SYNC= "now WAIT_FOR manage";
SELECT * FROM t1;
a b
SET DEBUG_SYNC= "now SIGNAL query";
# Connection default
# Reaping: ALTER TABLE t1 ADD UNIQUE (b)
SET DEBUG_SYNC= "RESET";
DROP TABLE t1;