MySQL 5.6 Release Notes
tcmalloc is no longer a permitted value for
the mysqld_safe
--malloc-lib option.
(Bug #31372027)
Incompatible Change:
Access to the
INFORMATION_SCHEMA.FILES table now
requires the PROCESS privilege.
This change affects users of the mysqldump
command, which accesses tablespace information in the
FILES table, and thus now requires
the PROCESS privilege as well.
Users who do not need to dump tablespace information can work
around this requirement by invoking mysqldump
with the --no-tablespaces
option.
(Bug #30350829)
The linked OpenSSL library for MySQL Server has been updated to version 1.1.1g. Issues fixed in the new OpenSSL version are described at https://www.openssl.org/news/cl111.txt and https://www.openssl.org/news/vulnerabilities.html. (Bug #31296697)
Partitioning:
A query against a partitioned table, which used an
ORDER BY, returned unordered results under
the following conditions:
The table had a composite index with a prefix on one of the columns.
The query's WHERE clause contained
an equality condition on the prefixed column.
The column with the prefix was the leftmost column in the index.
The column used in the ORDER BY was the
rightmost column in the index.
The index was used for handling the ORDER
BY.
Our thanks to Quanan Han for the suggestion. (Bug #84070, Bug #25207522)
Replication:
When a replication source server shuts down and restarts, its
MEMORY tables become empty. To
replicate this effect to replicas, the first time that the
source uses a given MEMORY table
after startup, it notifies replicas that the table must be
emptied by writing a DELETE
statement for that table to the binary log. Previously, the
generated DELETE statement was
written to the binary log statement cache for the current
session, which could result in it being logged together with
other statements under the same GTID, or logged without
BEGIN and COMMIT
statements. Also, in some situations, the generated
DELETE statement could consume
the GTID intended for the transaction that triggered it. The
generated DELETE statement is now
logged with accompanying BEGIN and
COMMIT statements, and the resulting
transaction is flushed to the binary log immediately after it is
written to the statement cache, so that it always receives its
own GTID and is kept separate from other transactions.
(Bug #30527929, Bug #25681518, Bug #77729)
mysql_store_result() could fail
to detect invalid data packets.
(Bug #29921423)
The server sometimes mistakenly removed a subquery with a
GROUP BY when optimizing a query, even in
some cases when this subquery was used by an outer select. This
could occur when the subquery also used an aggregate function.
(Bug #28240054)