Initialize sequence page under buffer content lock
Initialize sequence page under buffer content lock

Shared buffer access rules mandate that a pin as well as content lock
in exclusive mode is needed to update a shared buffer.

50wu/gpdb,ashwinstar/gpdb,adam8157/gpdb,ashwinstar/gpdb,50wu/gpdb,xinzweb/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,ashwinstar/gpdb,50wu/gpdb,ashwinstar/gpdb,lisakowen/gpdb,lisakowen/gpdb,adam8157/gpdb,xinzweb/gpdb,jmcatamney/gpdb,50wu/gpdb,jmcatamney/gpdb,adam8157/gpdb,adam8157/gpdb,greenplum-db/gpdb,jmcatamney/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,50wu/gpdb,50wu/gpdb,ashwinstar/gpdb,xinzweb/gpdb,jmcatamney/gpdb,xinzweb/gpdb,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,ashwinstar/gpdb,xinzweb/gpdb,greenplum-db/gpdb,adam8157/gpdb,xinzweb/gpdb,ashwinstar/gpdb,lisakowen/gpdb,lisakowen/gpdb,lisakowen/gpdb,xinzweb/gpdb,xinzweb/gpdb,adam8157/gpdb,lisakowen/gpdb,jmcatamney/gpdb,greenplum-db/gpdb,lisakowen/gpdb,jmcatamney/gpdb,lisakowen/gpdb,jmcatamney/gpdb,50wu/gpdb,greenplum-db/gpdb,adam8157/gpdb