Waiting for table lock on InnoDb tables

Hi all, this is my first post.

I am running MySQL 5.5.15. I have been load testing for high concurrency and with SHOW PROCESSLIST I see hundreds of lines like the following:

| 93165 | root | localhost:58503 | SITE_XXXXXXXX | Query | 73 | Waiting for table level lock | INSERT INTO Z_USER_LIST_ITEMS (LIST_ID, IDENTIFIER, PRODUCT_ID, SELLING_PRICE, ACCEPTED, |
| 93172 | root | localhost:58512 | SITE_XXXXXXXX | Query | 22 | Waiting for table level lock | INSERT INTO Z_PRODUCT_CACHE (PRODUCT_ID, MEDIA, TITLE, KEYWORDS, DT_STAMP)

These are simple single-line inserts. Both tables above are InnoDb, Z_USER_LIST_ITEMS has an auto-increment column, but Z_PRODUCT_CACHE does not.

I am at a loss as to why these inserts are seeking table level locks? This database serves a live website, and I have to prepare for much higher traffic and concurrency.

Hope someone can help!

Many thanks,
Mat

PS. Here is the output of SHOW VARIABLES:

auto_increment_increment 1
auto_increment_offset 1
autocommit ON
automatic_sp_privileges ON
back_log 50
basedir /usr/local/mysql
big_tables OFF
binlog_cache_size 32768
binlog_direct_non_transactional_updates OFF
binlog_format STATEMENT
binlog_stmt_cache_size 32768
bulk_insert_buffer_size 8388608
character_set_client utf8
character_set_connection utf8
character_set_database utf8
character_set_filesystem binary
character_set_results utf8
character_set_server utf8
character_set_system utf8
character_sets_dir /usr/local/mysql/share/charsets/
collation_connection utf8_general_ci
collation_database utf8_general_ci
collation_server utf8_general_ci
completion_type NO_CHAIN
concurrent_insert AUTO
connect_timeout 10
datadir /var/lib/mysql/
date_format %Y-%m-%d
datetime_format %Y-%m-%d %H:%i:%s
default_storage_engine InnoDB
default_week_format 0
delay_key_write ON
delayed_insert_limit 100
delayed_insert_timeout 300
delayed_queue_size 1000
div_precision_increment 4
engine_condition_pushdown ON
error_count 0
event_scheduler OFF
expire_logs_days 30
external_user
flush OFF
flush_time 0
foreign_key_checks ON
ft_boolean_syntax + -><()~*:""&|
ft_max_word_len 84
ft_min_word_len 4
ft_query_expansion_limit 20
ft_stopword_file (built-in)
general_log OFF
general_log_file /var/lib/mysql/semtex1.log
group_concat_max_len 1024
have_compress YES
have_crypt YES
have_csv YES
have_dynamic_loading YES
have_geometry YES
have_innodb YES
have_ndbcluster NO
have_openssl NO
have_partitioning YES
have_profiling YES
have_query_cache YES
have_rtree_keys YES
have_ssl NO
have_symlink YES
hostname semtex1
identity 0
ignore_builtin_innodb OFF
init_connect
init_file
init_slave
innodb_adaptive_flushing ON
innodb_adaptive_hash_index ON
innodb_additional_mem_pool_size 8388608
innodb_autoextend_increment 8
innodb_autoinc_lock_mode 1
innodb_buffer_pool_instances 1
innodb_buffer_pool_size 6123683840
innodb_change_buffering all
innodb_checksums ON
innodb_commit_concurrency 0
innodb_concurrency_tickets 500
innodb_data_file_path ibdata1:10M:autoextend
innodb_data_home_dir
innodb_doublewrite ON
innodb_fast_shutdown 1
innodb_file_format Antelope
innodb_file_format_check ON
innodb_file_format_max Antelope
innodb_file_per_table OFF
innodb_flush_log_at_trx_commit 1
innodb_flush_method
innodb_force_recovery 0
innodb_io_capacity 200
innodb_large_prefix OFF
innodb_lock_wait_timeout 50
innodb_locks_unsafe_for_binlog OFF
innodb_log_buffer_size 8388608
innodb_log_file_size 5242880
innodb_log_files_in_group 2
innodb_log_group_home_dir ./
innodb_max_dirty_pages_pct 75
innodb_max_purge_lag 0
innodb_mirrored_log_groups 1
innodb_old_blocks_pct 37
innodb_old_blocks_time 0
innodb_open_files 300
innodb_purge_batch_size 20
innodb_purge_threads 0
innodb_read_ahead_threshold 56
innodb_read_io_threads 4
innodb_replication_delay 0
innodb_rollback_on_timeout OFF
innodb_rollback_segments 128
innodb_spin_wait_delay 6
innodb_stats_method nulls_equal
innodb_stats_on_metadata ON
innodb_stats_sample_pages 8
innodb_strict_mode OFF
innodb_support_xa ON
innodb_sync_spin_loops 30
innodb_table_locks ON
innodb_thread_concurrency 16
innodb_thread_sleep_delay 10000
innodb_use_native_aio ON
innodb_use_sys_malloc ON
innodb_version 1.1.8
innodb_write_io_threads 4
insert_id 0
interactive_timeout 28800
join_buffer_size 134217728
keep_files_on_create OFF
key_buffer_size 268435456
key_cache_age_threshold 300
key_cache_block_size 1024
key_cache_division_limit 100
large_files_support ON
large_page_size 0
large_pages OFF
last_insert_id 0
lc_messages en_US
lc_messages_dir /usr/local/mysql/share/
lc_time_names en_US
license GPL
local_infile ON
lock_wait_timeout 31536000
locked_in_memory OFF
log OFF
log_bin ON
log_bin_trust_function_creators OFF
log_error /var/lib/mysql/semtex1.err
log_output FILE
log_queries_not_using_indexes OFF
log_slave_updates OFF
log_slow_queries OFF
log_warnings 1
long_query_time 10.000000
low_priority_updates ON
lower_case_file_system OFF
lower_case_table_names 0
max_allowed_packet 402653184
max_binlog_cache_size 18446744073709547520
max_binlog_size 1073741824
max_binlog_stmt_cache_size 18446744073709547520
max_connect_errors 10
max_connections 1000
max_delayed_threads 20
max_error_count 64
max_heap_table_size 134217728
max_insert_delayed_threads 20
max_join_size 18446744073709551615
max_length_for_sort_data 1024
max_long_data_size 402653184
max_prepared_stmt_count 16382
max_relay_log_size 0
max_seeks_for_key 18446744073709551615
max_sort_length 1024
max_sp_recursion_depth 0
max_tmp_tables 32
max_user_connections 0
max_write_lock_count 18446744073709551615
min_examined_row_limit 0
multi_range_count 256
myisam_data_pointer_size 6
myisam_max_sort_file_size 9223372036853727232
myisam_mmap_size 18446744073709551615
myisam_recover_options OFF
myisam_repair_threads 1
myisam_sort_buffer_size 268435456
myisam_stats_method nulls_unequal
myisam_use_mmap OFF
net_buffer_length 16384
net_read_timeout 30
net_retry_count 10
net_write_timeout 60
new OFF
old OFF
old_alter_table OFF
old_passwords OFF
open_files_limit 5000
optimizer_prune_level 1
optimizer_search_depth 62
optimizer_switch index_merge=on,index_merge_union=on,index_merge_sort_union=o n,index_merge_intersection=on,engine_condition_pushdown=on
performance_schema OFF
performance_schema_events_waits_history_long_size 10000
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performance_schema_max_file_handles 32768
performance_schema_max_file_instances 10000
performance_schema_max_mutex_classes 200
performance_schema_max_mutex_instances 1000000
performance_schema_max_rwlock_classes 30
performance_schema_max_rwlock_instances 1000000
performance_schema_max_table_handles 100000
performance_schema_max_table_instances 50000
performance_schema_max_thread_classes 50
performance_schema_max_thread_instances 1000
pid_file /tmp/mysql.pid
plugin_dir /usr/local/mysql/lib/plugin
port 3306
preload_buffer_size 32768
profiling OFF
profiling_history_size 15
protocol_version 10
proxy_user
pseudo_thread_id 300
query_alloc_block_size 8192
query_cache_limit 268435456
query_cache_min_res_unit 4096
query_cache_size 822083584
query_cache_type ON
query_cache_wlock_invalidate OFF
query_prealloc_size 8192
rand_seed1 0
rand_seed2 0
range_alloc_block_size 4096
read_buffer_size 134217728
read_only OFF
read_rnd_buffer_size 262144
relay_log
relay_log_index
relay_log_info_file relay-log.info
relay_log_purge ON
relay_log_recovery OFF
relay_log_space_limit 0
report_host
report_password
report_port 3306
report_user
rpl_recovery_rank 0
secure_auth OFF
secure_file_priv
server_id 1
skip_external_locking ON
skip_name_resolve OFF
skip_networking OFF
skip_show_database OFF
slave_compressed_protocol OFF
slave_exec_mode STRICT
slave_load_tmpdir /tmp
slave_net_timeout 3600
slave_skip_errors OFF
slave_transaction_retries 10
slave_type_conversions
slow_launch_time 2
slow_query_log OFF
slow_query_log_file /var/lib/mysql/semtex1-slow.log
socket /tmp/mysql.sock
sort_buffer_size 134217728
sql_auto_is_null OFF
sql_big_selects ON
sql_big_tables OFF
sql_buffer_result OFF
sql_log_bin ON
sql_log_off OFF
sql_low_priority_updates ON
sql_max_join_size 18446744073709551615
sql_mode
sql_notes ON
sql_quote_show_create ON
sql_safe_updates OFF
sql_select_limit 18446744073709551615
sql_slave_skip_counter 0
sql_warnings OFF
ssl_ca
ssl_capath
ssl_cert
ssl_cipher
ssl_key
storage_engine InnoDB
sync_binlog 0
sync_frm ON
sync_master_info 0
sync_relay_log 0
sync_relay_log_info 0
system_time_zone BST
table_definition_cache 400
table_open_cache 1024
thread_cache_size 64
thread_concurrency 10
thread_handling one-thread-per-connection
thread_stack 262144
time_format %H:%i:%s
time_zone SYSTEM
timed_mutexes OFF
timestamp 1343310310
tmp_table_size 16777216
tmpdir /tmp
transaction_alloc_block_size 8192
transaction_prealloc_size 4096
tx_isolation REPEATABLE-READ
unique_checks ON
updatable_views_with_limit YES
version 5.5.15-log
version_comment Source distribution
version_compile_machine x86_64
version_compile_os Linux
wait_timeout 28800
warning_count 0

Can you post the full output of

SHOW ENGINE INNODB STATUS\G,
SHOW FULL PROCESSLIST

while the incident is happening ?

and also,

SHOW CREATE TABLE Z_USER_LIST_ITEMS\G
SHOW CREATE TABLE Z_PRODUCT_CACHE\G

Hiya,

I’ve managed to resolve the problem. The InnoDb tables had triggers which performed INSERT DELAYED on MyISAM tables. I only discovered today that INSERT DELAYED is not supported in stored procedures or triggers, and the processes were actually waiting for locks on these MyISAM tables.

Thanks for your help.

Mat