diff --git a/.gitignore b/.gitignore
index 658f35a..d54f41e 100644
--- a/.gitignore
+++ b/.gitignore
@@ -1 +1 @@
-/mysql-5.5.27-nodocs.tar.gz
+/mysql-5.5.28-nodocs.tar.gz
diff --git a/libmysql.version b/libmysql.version
index dc32cd7..d547b5d 100644
--- a/libmysql.version
+++ b/libmysql.version
@@ -117,6 +117,9 @@ libmysqlclient_16 {
 # de-facto API as well.  We're not going to export the deprecated version
 # make_scrambled_password, however.
 	my_make_scrambled_password;
+# This really shouldn't be exported, but some applications use it as a
+# workaround for inadequate threading support; see bug #846602
+	THR_KEY_mysys;
   local:
 	*;
 };
diff --git a/mysql-chain-certs.patch b/mysql-chain-certs.patch
index 3b20a28..164c22e 100644
--- a/mysql-chain-certs.patch
+++ b/mysql-chain-certs.patch
@@ -10,22 +10,10 @@ Fedora builds, I'm not feeling motivated to try to fix yassl for this.
 See RH bug #598656.  Filed upstream at http://bugs.mysql.com/bug.php?id=54158
 
 
-diff -Naur mysql-5.1.47.orig/vio/viosslfactories.c mysql-5.1.47/vio/viosslfactories.c
---- mysql-5.1.47.orig/vio/viosslfactories.c	2010-05-06 11:28:07.000000000 -0400
-+++ mysql-5.1.47/vio/viosslfactories.c	2010-05-26 23:23:46.000000000 -0400
-@@ -100,7 +100,7 @@
- 		       (long) ctx, cert_file, key_file));
-   if (cert_file)
-   {
--    if (SSL_CTX_use_certificate_file(ctx, cert_file, SSL_FILETYPE_PEM) <= 0)
-+    if (SSL_CTX_use_certificate_chain_file(ctx, cert_file) <= 0)
-     {
-       *error= SSL_INITERR_CERT;
-       DBUG_PRINT("error",("%s from file '%s'", sslGetErrString(*error), cert_file));
-diff -Naur mysql-5.1.47.orig/extra/yassl/src/ssl.cpp mysql-5.1.47/extra/yassl/src/ssl.cpp
---- mysql-5.1.47.orig/extra/yassl/src/ssl.cpp	2010-05-06 11:24:26.000000000 -0400
-+++ mysql-5.1.47/extra/yassl/src/ssl.cpp	2010-05-26 23:29:13.000000000 -0400
-@@ -1606,10 +1606,10 @@
+diff -Naur mysql-5.5.28.orig/extra/yassl/src/ssl.cpp mysql-5.5.28/extra/yassl/src/ssl.cpp
+--- mysql-5.5.28.orig/extra/yassl/src/ssl.cpp	2012-08-29 04:50:46.000000000 -0400
++++ mysql-5.5.28/extra/yassl/src/ssl.cpp	2012-09-29 12:45:19.682287214 -0400
+@@ -1627,10 +1627,10 @@
      }
  
  
@@ -39,3 +27,15 @@ diff -Naur mysql-5.1.47.orig/extra/yassl/src/ssl.cpp mysql-5.1.47/extra/yassl/sr
      }
  
  
+diff -Naur mysql-5.5.28.orig/vio/viosslfactories.c mysql-5.5.28/vio/viosslfactories.c
+--- mysql-5.5.28.orig/vio/viosslfactories.c	2012-08-29 04:50:46.000000000 -0400
++++ mysql-5.5.28/vio/viosslfactories.c	2012-09-29 12:46:35.124975585 -0400
+@@ -106,7 +106,7 @@
+     key_file= cert_file;
+ 
+   if (cert_file &&
+-      SSL_CTX_use_certificate_file(ctx, cert_file, SSL_FILETYPE_PEM) <= 0)
++      SSL_CTX_use_certificate_chain_file(ctx, cert_file) <= 0)
+   {
+     *error= SSL_INITERR_CERT;
+     DBUG_PRINT("error",("%s from file '%s'", sslGetErrString(*error), cert_file));
diff --git a/mysql-openssl-test.patch b/mysql-openssl-test.patch
deleted file mode 100644
index f7e8f43..0000000
--- a/mysql-openssl-test.patch
+++ /dev/null
@@ -1,22 +0,0 @@
-Adjust openssl_1.result to match actual output when using OpenSSL.
-
-The given expected result seems to be yaSSL-specific, as of mysql 5.5.14.
-Upstream at http://bugs.mysql.com/bug.php?id=61827
-
-
-diff -Naur mysql-5.5.14.orig/mysql-test/r/openssl_1.result mysql-5.5.14/mysql-test/r/openssl_1.result
---- mysql-5.5.14.orig/mysql-test/r/openssl_1.result	2011-06-21 12:42:40.000000000 -0400
-+++ mysql-5.5.14/mysql-test/r/openssl_1.result	2011-07-11 18:52:39.925070616 -0400
-@@ -44,9 +44,9 @@
- drop user ssl_user1@localhost, ssl_user2@localhost,
- ssl_user3@localhost, ssl_user4@localhost, ssl_user5@localhost;
- drop table t1;
--mysqltest: Could not open connection 'default': 2026 SSL connection error: ASN: bad other signature confirmation
--mysqltest: Could not open connection 'default': 2026 SSL connection error: ASN: bad other signature confirmation
--mysqltest: Could not open connection 'default': 2026 SSL connection error: ASN: bad other signature confirmation
-+mysqltest: Could not open connection 'default': 2026 SSL connection error: error:00000001:lib(0):func(0):reason(1)
-+mysqltest: Could not open connection 'default': 2026 SSL connection error: error:00000001:lib(0):func(0):reason(1)
-+mysqltest: Could not open connection 'default': 2026 SSL connection error: error:00000001:lib(0):func(0):reason(1)
- SSL error: Unable to get private key from ''
- mysqltest: Could not open connection 'default': 2026 SSL connection error: Unable to get private key
- SSL error: Unable to get certificate from ''
diff --git a/mysql.spec b/mysql.spec
index 121f96b..dff5a8e 100644
--- a/mysql.spec
+++ b/mysql.spec
@@ -1,5 +1,5 @@
 Name: mysql
-Version: 5.5.27
+Version: 5.5.28
 Release: 1%{?dist}
 
 Summary: MySQL client programs and shared libraries
@@ -48,7 +48,6 @@ Patch7: mysql-versioning.patch
 Patch8: mysql-dubious-exports.patch
 Patch10: mysql-plugin-bool.patch
 Patch11: mysql-s390-tsc.patch
-Patch12: mysql-openssl-test.patch
 Patch14: mysql-va-list.patch
 Patch15: mysql-netdevname.patch
 Patch16: mysql-logrotate.patch
@@ -203,7 +202,6 @@ the MySQL sources.
 %patch8 -p1
 %patch10 -p1
 %patch11 -p1
-%patch12 -p1
 %patch14 -p1
 %patch15 -p1
 %patch16 -p1
@@ -459,10 +457,14 @@ rm -rf $RPM_BUILD_ROOT
 /sbin/ldconfig
 
 %post server
+%if 0%{?systemd_post:1}
+%systemd_post mysqld.service
+%else
 if [ $1 = 1 ]; then
     # Initial installation
     /bin/systemctl daemon-reload >/dev/null 2>&1 || :
 fi
+%endif
 /bin/chmod 0755 /var/lib/mysql
 /bin/touch /var/log/mysqld.log
 
@@ -482,11 +484,15 @@ if [ -f /etc/rc.d/init.d/mysqld ]; then
 fi
 
 %preun server
+%if 0%{?systemd_preun:1}
+%systemd_preun mysqld.service
+%else
 if [ $1 = 0 ]; then
     # Package removal, not upgrade
     /bin/systemctl --no-reload disable mysqld.service >/dev/null 2>&1 || :
     /bin/systemctl stop mysqld.service >/dev/null 2>&1 || :
 fi
+%endif
 
 %postun libs
 if [ $1 = 0 ] ; then
@@ -494,11 +500,15 @@ if [ $1 = 0 ] ; then
 fi
 
 %postun server
+%if 0%{?systemd_postun_with_restart:1}
+%systemd_postun_with_restart mysqld.service
+%else
 /bin/systemctl daemon-reload >/dev/null 2>&1 || :
 if [ $1 -ge 1 ]; then
     # Package upgrade, not uninstall
     /bin/systemctl try-restart mysqld.service >/dev/null 2>&1 || :
 fi
+%endif
 
 
 %files
@@ -691,6 +701,20 @@ fi
 %{_mandir}/man1/mysql_client_test.1*
 
 %changelog
+* Sat Sep 29 2012 Tom Lane <tgl@redhat.com> 5.5.28-1
+- Update to MySQL 5.5.28, for various fixes described at
+  http://dev.mysql.com/doc/refman/5.5/en/news-5-5-28.html
+- Clean up partially-created database files when mysql_install_db fails
+Related: #835131
+- Honor user and group settings from service file in mysqld-prepare-db-dir
+Resolves: #840431
+- Export THR_KEY_mysys as a workaround for inadequate threading support
+Resolves: #846602
+- Adopt new systemd macros for server package install/uninstall triggers
+Resolves: #850222
+- Use --no-defaults when invoking mysqladmin to wait for the server to start
+Related: #855704
+
 * Sun Aug  5 2012 Tom Lane <tgl@redhat.com> 5.5.27-1
 - Update to MySQL 5.5.27, for various fixes described at
   http://dev.mysql.com/doc/refman/5.5/en/news-5-5-27.html
diff --git a/mysqld-prepare-db-dir b/mysqld-prepare-db-dir
index 78c0bd7..f73bc66 100644
--- a/mysqld-prepare-db-dir
+++ b/mysqld-prepare-db-dir
@@ -22,10 +22,31 @@ datadir="$result"
 get_mysql_option mysqld_safe log-error "/var/log/mysqld.log"
 errlogfile="$result"
 
+# Absorb configuration settings from the specified systemd service file,
+# or the default "mysqld" service if not specified
+SERVICE_NAME="$1"
+if [ x"$SERVICE_NAME" = x ]
+then
+    SERVICE_NAME=mysqld.service
+fi
+
+myuser=`systemctl show -p User "${SERVICE_NAME}" |
+  sed 's/^User=//'`
+if [ x"$myuser" = x ]
+then
+    myuser=mysql
+fi
+
+mygroup=`systemctl show -p Group "${SERVICE_NAME}" |
+  sed 's/^Group=//'`
+if [ x"$mygroup" = x ]
+then
+    mygroup=mysql
+fi
 
 # Set up the errlogfile with appropriate permissions
 touch "$errlogfile"
-chown mysql:mysql "$errlogfile"
+chown "$myuser:$mygroup" "$errlogfile"
 chmod 0640 "$errlogfile"
 [ -x /sbin/restorecon ] && /sbin/restorecon "$errlogfile"
 
@@ -37,13 +58,13 @@ if [ ! -d "$datadir/mysql" ] ; then
     then
         mkdir -p "$datadir" || exit 1
     fi
-    chown mysql:mysql "$datadir"
+    chown "$myuser:$mygroup" "$datadir"
     chmod 0755 "$datadir"
     [ -x /sbin/restorecon ] && /sbin/restorecon "$datadir"
 
     # Now create the database
     echo "Initializing MySQL database"
-    /usr/bin/mysql_install_db --datadir="$datadir" --user=mysql
+    /usr/bin/mysql_install_db --datadir="$datadir" --user="$myuser"
     ret=$?
     if [ $ret -ne 0 ] ; then
         echo "Initialization of MySQL database failed." >&2
@@ -55,7 +76,7 @@ if [ ! -d "$datadir/mysql" ] ; then
         exit $ret
     fi
     # In case we're running as root, make sure files are owned properly
-    chown -R mysql:mysql "$datadir"
+    chown -R "$myuser:$mygroup" "$datadir"
 fi
 
 exit 0
diff --git a/mysqld-wait-ready b/mysqld-wait-ready
index 8fe99ec..9b0fd0c 100644
--- a/mysqld-wait-ready
+++ b/mysqld-wait-ready
@@ -31,7 +31,7 @@ socketfile="$result"
 # Wait for the server to come up or for the mysqld process to disappear
 ret=0
 while /bin/true; do
-	RESPONSE=`/usr/bin/mysqladmin --socket="$socketfile" --user=UNKNOWN_MYSQL_USER ping 2>&1`
+	RESPONSE=`/usr/bin/mysqladmin --no-defaults --socket="$socketfile" --user=UNKNOWN_MYSQL_USER ping 2>&1`
 	mret=$?
 	if [ $mret -eq 0 ]; then
 	    break
diff --git a/mysqld.service b/mysqld.service
index c6e4dea..3193ce2 100644
--- a/mysqld.service
+++ b/mysqld.service
@@ -27,7 +27,7 @@ Type=simple
 User=mysql
 Group=mysql
 
-ExecStartPre=/usr/libexec/mysqld-prepare-db-dir
+ExecStartPre=/usr/libexec/mysqld-prepare-db-dir %n
 # Note: we set --basedir to prevent probes that might trigger SELinux alarms,
 # per bug #547485
 ExecStart=/usr/bin/mysqld_safe --basedir=/usr
diff --git a/sources b/sources
index ca44937..0e73348 100644
--- a/sources
+++ b/sources
@@ -1 +1 @@
-fc115ac6b28412298886651cffc70ccf  mysql-5.5.27-nodocs.tar.gz
+88d39960d3f348836f803aca091ee601  mysql-5.5.28-nodocs.tar.gz