memory-high-water

:
# ------------------------------------------------------------
# memory-high-water
#
# Try to give a rough estimate of the maximum memory usage
# expected from a given instance of MySQL or Percona Server.
#
# THIS IS KNOWN TO BE INACCURATE; there are some uses of memory by
# mysqld that aren't represented by this formula.
#
# There are also some figures (join_buffer_size, tmp_table_size) that
# might be allocated more than once per thread, depending on the query.
#
# So you can use the formula to give you a reminder of some (but not all)
# of the potential consumption of memory in mysqld.
#
# Copyright 2012 Bill Karwin.
# 
# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.
# 
# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.
# 
# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.
#
# ------------------------------------------------------------

: ${MYSQL:="mysql"}
: ${MYSQL_OPTIONS:=""}

${MYSQL} ${MYSQL_OPTIONS} -B -E --silent <<_SQL_
SELECT CONCAT((
    @@key_buffer_size
  + @@query_cache_size
  + (@@innodb_buffer_pool_size * 1.05 + 20*1024*1024)
  + @@innodb_additional_mem_pool_size
  + @@innodb_log_buffer_size
  + @@max_connections * (
      @@read_buffer_size
    + @@read_rnd_buffer_size
    + @@sort_buffer_size
    + @@join_buffer_size
    + @@binlog_cache_size
    + @@tmp_table_size
    + @@thread_stack)) / 1024/1024/1024,
  ' GB') AS "POTENTIAL MEMORY USAGE";
_SQL_