maria-developers team mailing list archive

[Sergey Petrunia <sergey@xxxxxxxxxxx>]

Hi,

Daniel Vratil from Akonadi (a PIM manager for KDE) has asked me at FOSDEM about
optimal MariaDB configuration for Akonadi.

Some specific questions:
* innodb_flush_log_at_trx_commit. Currently, Akonadi uses
innodb_flush_log_at_trx_commit=2 which as far as I understand can cause up to 1
second of changes to be lost. Using value of 1 (always flush on commit) should 
be safer, but maybe it would put an unnecessary load on the system? Akonadi's 
use case has a bit different idea of what load is - there is only one person 
making changes, but the system is likely to be a laptop where one cares about 
battery life, etc.

* innodb_buffer_pool_size=80M. The dataset size can vary from very small to up
to 1-1.5Gb.  Some users have very little data and complain that 80M is too much. 
Does anybody have an experience with using very small innodb_buffer_pool_size?

Please find the full config file below:

=== Akonadi configuration file ===
# These settings can be adjusted using $HOME/.config/akonadi/mysql-local.conf
#
# Based on advice by Kris Köhntopp <kris@xxxxxxxxx>
#
[mysqld]

# strict query parsing/interpretation
# TODO: make Akonadi work with those settings enabled
# sql_mode=strict_trans_tables,strict_all_tables,strict_error_for_division_by_zero,no_auto_create_user,no_auto_value_on_zero,no_engine_substitution,no_zero_date,no_zero_in_date,only_full_group_by,pipes_as_concat
# sql_mode=strict_trans_tables

# DEBUGGING:
# log all queries, useful for debugging but generates an enormous amount of data
# log=mysql.full
# log queries slower than n seconds, log file name relative to datadir (for debugging only)
# log_slow_queries=mysql.slow
# long_query_time=1
# log queries not using indices, debug only, disable for production use
# log_queries_not_using_indexes=1
#
# mesure database size and adjust innodb_buffer_pool_size
# SELECT sum(data_length) as bla, sum(index_length) as blub FROM information_schema.tables WHERE table_schema not in ("mysql", "information_schema");

# NOTES:
# Keep Innob_log_waits and keep Innodb_buffer_pool_wait_free small (see show global status like "inno%", show global variables)

#expire_logs_days=3

#sync_bin_log=0

# Use UTF-8 encoding for tables
character_set_server=utf8
collation_server=utf8_general_ci

# use InnoDB for transactions and better crash recovery
default_storage_engine=innodb

# memory pool InnoDB uses to store data dictionary information and other internal data structures (default:1M)
# Deprecated in MySQL >= 5.6.3
innodb_additional_mem_pool_size=1M

# memory buffer InnoDB uses to cache data and indexes of its tables (default:128M)
# Larger values means less I/O
innodb_buffer_pool_size=80M

# Create a .ibd file for each table (default:0)
innodb_file_per_table=1

# Write out the log buffer to the log file at each commit (default:1)
innodb_flush_log_at_trx_commit=2

# Buffer size used to write to the log files on disk (default:1M for builtin, 8M for plugin)
# larger values means less I/O
innodb_log_buffer_size=1M

# Size of each log file in a log group (default:5M) larger means less I/O but more time for recovery.
innodb_log_file_size=64M

# # error log file name, relative to datadir (default:hostname.err)
log_error=mysql.err

# print warnings and connection errors (default:1)
log_warnings=2

# Convert table named to lowercase
lower_case_table_names=1

# Maximum size of one packet or any generated/intermediate string. (default:1M)
max_allowed_packet=32M

# Maximum simultaneous connections allowed (default:100)
max_connections=256

# The two options below make no sense with prepared statements and/or transactions
# (make sense when having the same query multiple times)

# Memory allocated for caching query results (default:0 (disabled))
query_cache_size=0

# Do not cache results (default:1)
query_cache_type=0

# Do not use the privileges mechanisms
skip_grant_tables

# Do not listen for TCP/IP connections at all
skip_networking

# The number of open tables for all threads. (default:64)
table_open_cache=200

# How many threads the server should cache for reuse (default:0)
thread_cache_size=3

# wait 365d before dropping the DB connection (default:8h)
wait_timeout=31536000

# We use InnoDB, so don't let MyISAM eat up memory
key_buffer_size=16K

[client]
default-character-set=utf8

BR
 Sergei
-- 
Sergei Petrunia, Software Developer
MariaDB | Skype: sergefp | Blog: http://s.petrunia.net/blog