I recently upgraded a light-duty (running just a handful of smallish WordPress sites at the moment) MAMP server (first "M" is for "Mac", it's not the MAMP package install but individually installed source components via MacPorts) to PHP7 and MySQL 5.7, and though it's mostly been smooth I'm experiencing intermittent instances where the web site errors while trying to connect to the db. The same sites worked fine on PHP5.3 with MySQL 5.5.
I get similar problems when accessing MySQL via commandline (Got error: 2013: Lost connection to MySQL server at 'reading initial communication packet', system error: 102 when trying to connect), so I'm pretty sure it's not primarily a PHP7 problem.
I've updated various tables (changing default dates from 0000-00-00 00:00:00 to CURRENT_TIMESTAMP, for instance) and tried tweaking some settings, but I'm a bit new at that level of detail. I've searched a fair bit and haven't come up with a clear path forward. I'm hoping one of you can look at the current variable settings below and quickly see what's amiss.
Thanks in advance!
auto_increment_increment 1
auto_increment_offset 1
autocommit ON
automatic_sp_privileges ON
avoid_temporal_upgrade OFF
back_log 100
basedir /opt/local/
big_tables OFF
bind_address *
binlog_cache_size 32768
binlog_checksum CRC32
binlog_direct_non_transactional_updates OFF
binlog_error_action ABORT_SERVER
binlog_format ROW
binlog_group_commit_sync_delay 0
binlog_group_commit_sync_no_delay_count 0
binlog_gtid_simple_recovery ON
binlog_max_flush_queue_time 0
binlog_order_commits ON
binlog_row_image FULL
binlog_rows_query_log_events OFF
binlog_stmt_cache_size 32768
block_encryption_mode aes-128-ecb
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 /opt/local/share/mysql57/charsets/
check_proxy_users OFF
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
core_file OFF
datadir /opt/local/var/db/mysql57/
date_format %Y-%m-%d
datetime_format %Y-%m-%d %H:%i:%s
default_authentication_plugin mysql_native_password
default_password_lifetime 0
default_storage_engine InnoDB
default_tmp_storage_engine InnoDB
default_week_format 0
delay_key_write ON
delayed_insert_limit 100
delayed_insert_timeout 300
delayed_queue_size 1000
disabled_storage_engines
disconnect_on_expired_password ON
div_precision_increment 4
end_markers_in_json OFF
enforce_gtid_consistency OFF
eq_range_index_dive_limit 200
event_scheduler OFF
expire_logs_days 0
explicit_defaults_for_timestamp OFF
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 /opt/local/var/db/mysql57/254.log
group_concat_max_len 1024
gtid_executed
gtid_executed_compression_period 1000
gtid_mode OFF
gtid_owned
gtid_purged
have_compress YES
have_crypt YES
have_dynamic_loading YES
have_geometry YES
have_openssl YES
have_profiling YES
have_query_cache YES
have_rtree_keys YES
have_ssl YES
have_statement_timeout YES
have_symlink YES
host_cache_size 378
hostname 254.domain.com
ignore_builtin_innodb OFF
ignore_db_dirs
init_connect
init_file
init_slave
innodb_adaptive_flushing ON
innodb_adaptive_flushing_lwm 10
innodb_adaptive_hash_index ON
innodb_adaptive_hash_index_parts 8
innodb_adaptive_max_sleep_delay 150000
innodb_api_bk_commit_interval 5
innodb_api_disable_rowlock OFF
innodb_api_enable_binlog OFF
innodb_api_enable_mdl OFF
innodb_api_trx_level 0
innodb_autoextend_increment 64
innodb_autoinc_lock_mode 1
innodb_buffer_pool_chunk_size 134217728
innodb_buffer_pool_dump_at_shutdown ON
innodb_buffer_pool_dump_now OFF
innodb_buffer_pool_dump_pct 25
innodb_buffer_pool_filename ib_buffer_pool
innodb_buffer_pool_instances 1
innodb_buffer_pool_load_abort OFF
innodb_buffer_pool_load_at_startup ON
innodb_buffer_pool_load_now OFF
innodb_buffer_pool_size 268435456
innodb_change_buffer_max_size 25
innodb_change_buffering all
innodb_checksum_algorithm crc32
innodb_checksums ON
innodb_cmp_per_index_enabled OFF
innodb_commit_concurrency 0
innodb_compression_failure_threshold_pct 5
innodb_compression_level 6
innodb_compression_pad_pct_max 50
innodb_concurrency_tickets 5000
innodb_data_file_path ibdata1:12M:autoextend
innodb_data_home_dir
innodb_deadlock_detect ON
innodb_default_row_format dynamic
innodb_disable_sort_file_cache OFF
innodb_doublewrite ON
innodb_fast_shutdown 1
innodb_file_format Barracuda
innodb_file_format_check ON
innodb_file_format_max Barracuda
innodb_file_per_table ON
innodb_fill_factor 100
innodb_flush_log_at_timeout 1
innodb_flush_log_at_trx_commit 1
innodb_flush_method
innodb_flush_neighbors 1
innodb_flush_sync ON
innodb_flushing_avg_loops 30
innodb_force_load_corrupted OFF
innodb_force_recovery 0
innodb_ft_aux_table
innodb_ft_cache_size 8000000
innodb_ft_enable_diag_print OFF
innodb_ft_enable_stopword ON
innodb_ft_max_token_size 84
innodb_ft_min_token_size 3
innodb_ft_num_word_optimize 2000
innodb_ft_result_cache_limit 2000000000
innodb_ft_server_stopword_table
innodb_ft_sort_pll_degree 2
innodb_ft_total_cache_size 640000000
innodb_ft_user_stopword_table
innodb_io_capacity 200
innodb_io_capacity_max 2000
innodb_large_prefix ON
innodb_lock_wait_timeout 50
innodb_locks_unsafe_for_binlog OFF
innodb_log_buffer_size 16777216
innodb_log_checksums ON
innodb_log_compressed_pages ON
innodb_log_file_size 67108864
innodb_log_files_in_group 2
innodb_log_group_home_dir ./
innodb_log_write_ahead_size 8192
innodb_lru_scan_depth 1024
innodb_max_dirty_pages_pct 75.000000
innodb_max_dirty_pages_pct_lwm 0.000000
innodb_max_purge_lag 0
innodb_max_purge_lag_delay 0
innodb_max_undo_log_size 1073741824
innodb_monitor_disable
innodb_monitor_enable
innodb_monitor_reset
innodb_monitor_reset_all
innodb_old_blocks_pct 37
innodb_old_blocks_time 1000
innodb_online_alter_log_max_size 134217728
innodb_open_files 2000
innodb_optimize_fulltext_only OFF
innodb_page_cleaners 1
innodb_page_size 16384
innodb_print_all_deadlocks OFF
innodb_purge_batch_size 300
innodb_purge_rseg_truncate_frequency 128
innodb_purge_threads 4
innodb_random_read_ahead OFF
innodb_read_ahead_threshold 56
innodb_read_io_threads 4
innodb_read_only OFF
innodb_replication_delay 0
innodb_rollback_on_timeout OFF
innodb_rollback_segments 128
innodb_sort_buffer_size 1048576
innodb_spin_wait_delay 6
innodb_stats_auto_recalc ON
innodb_stats_include_delete_marked OFF
innodb_stats_method nulls_equal
innodb_stats_on_metadata OFF
innodb_stats_persistent ON
innodb_stats_persistent_sample_pages 20
innodb_stats_sample_pages 8
innodb_stats_transient_sample_pages 8
innodb_status_output OFF
innodb_status_output_locks OFF
innodb_strict_mode ON
innodb_support_xa ON
innodb_sync_array_size 1
innodb_sync_spin_loops 30
innodb_table_locks ON
innodb_temp_data_file_path ibtmp1:12M:autoextend
innodb_thread_concurrency 0
innodb_thread_sleep_delay 10000
innodb_tmpdir
innodb_undo_directory ./
innodb_undo_log_truncate OFF
innodb_undo_logs 128
innodb_undo_tablespaces 0
innodb_use_native_aio OFF
innodb_version 5.7.17
innodb_write_io_threads 4
interactive_timeout 28800
internal_tmp_disk_storage_engine InnoDB
join_buffer_size 262144
keep_files_on_create OFF
key_buffer_size 8388608
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
lc_messages en_US
lc_messages_dir /opt/local/share/mysql57/
lc_time_names en_US
license GPL
local_infile ON
lock_wait_timeout 31536000
locked_in_memory OFF
log_bin OFF
log_bin_basename
log_bin_index
log_bin_trust_function_creators OFF
log_bin_use_v1_row_events OFF
log_builtin_as_identified_by_password OFF
log_error stderr
log_error_verbosity 3
log_output FILE
log_queries_not_using_indexes OFF
log_slave_updates OFF
log_slow_admin_statements OFF
log_slow_slave_statements OFF
log_statements_unsafe_for_binlog ON
log_syslog OFF
log_syslog_facility daemon
log_syslog_include_pid ON
log_syslog_tag
log_throttle_queries_not_using_indexes 0
log_timestamps UTC
log_warnings 2
long_query_time 10.000000
low_priority_updates OFF
lower_case_file_system ON
lower_case_table_names 2
master_info_repository FILE
master_verify_checksum OFF
max_allowed_packet 4194304
max_binlog_cache_size 18446744073709547520
max_binlog_size 1073741824
max_binlog_stmt_cache_size 18446744073709547520
max_connect_errors 100
max_connections 250
max_delayed_threads 20
max_digest_length 1024
max_error_count 64
max_execution_time 0
max_heap_table_size 33554432
max_insert_delayed_threads 20
max_join_size 18446744073709551615
max_length_for_sort_data 1024
max_points_in_geometry 65536
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
metadata_locks_cache_size 1024
metadata_locks_hash_instances 8
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 8388608
myisam_stats_method nulls_unequal
myisam_use_mmap OFF
mysql_native_password_proxy_users OFF
net_buffer_length 16384
net_read_timeout 30
net_retry_count 10
net_write_timeout 60
new OFF
ngram_token_size 2
offline_mode OFF
old OFF
old_alter_table OFF
old_passwords 0
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=on,index_merge_intersection=on,engine_condition_pushdown=on,index_condition_pushdown=on,mrr=on,mrr_cost_based=on,block_nested_loop=on,batched_key_access=off,materialization=on,semijoin=on,loosescan=on,firstmatch=on,duplicateweedout=on,subquery_materialization_cost_based=on,use_index_extensions=on,condition_fanout_filter=on,derived_merge=on
optimizer_trace enabled=off,one_line=off
optimizer_trace_features greedy_search=on,range_optimizer=on,dynamic_range=on,repeated_subselect=on
optimizer_trace_limit 1
optimizer_trace_max_mem_size 16384
optimizer_trace_offset -1
parser_max_mem_size 18446744073709551615
performance_schema ON
performance_schema_accounts_size -1
performance_schema_digests_size 10000
performance_schema_events_stages_history_long_size 10000
performance_schema_events_stages_history_size 10
performance_schema_events_statements_history_long_size 10000
performance_schema_events_statements_history_size 10
performance_schema_events_transactions_history_long_size 10000
performance_schema_events_transactions_history_size 10
performance_schema_events_waits_history_long_size 10000
performance_schema_events_waits_history_size 10
performance_schema_hosts_size -1
performance_schema_max_cond_classes 80
performance_schema_max_cond_instances -1
performance_schema_max_digest_length 1024
performance_schema_max_file_classes 80
performance_schema_max_file_handles 32768
performance_schema_max_file_instances -1
performance_schema_max_index_stat -1
performance_schema_max_memory_classes 320
performance_schema_max_metadata_locks -1
performance_schema_max_mutex_classes 200
performance_schema_max_mutex_instances -1
performance_schema_max_prepared_statements_instances -1
performance_schema_max_program_instances -1
performance_schema_max_rwlock_classes 40
performance_schema_max_rwlock_instances -1
performance_schema_max_socket_classes 10
performance_schema_max_socket_instances -1
performance_schema_max_sql_text_length 1024
performance_schema_max_stage_classes 150
performance_schema_max_statement_classes 193
performance_schema_max_statement_stack 10
performance_schema_max_table_handles -1
performance_schema_max_table_instances -1
performance_schema_max_table_lock_stat -1
performance_schema_max_thread_classes 50
performance_schema_max_thread_instances -1
performance_schema_session_connect_attrs_size 512
performance_schema_setup_actors_size -1
performance_schema_setup_objects_size -1
performance_schema_users_size -1
pid_file /opt/local/var/db/mysql57/254.sustainablesources.pid
plugin_dir /opt/local/lib/mysql57/plugin/
port 0
preload_buffer_size 32768
profiling OFF
profiling_history_size 15
protocol_version 10
query_alloc_block_size 8192
query_cache_limit 1048576
query_cache_min_res_unit 4096
query_cache_size 1048576
query_cache_type OFF
query_cache_wlock_invalidate OFF
query_prealloc_size 8192
range_alloc_block_size 4096
range_optimizer_max_mem_size 8388608
rbr_exec_mode STRICT
read_buffer_size 131072
read_only OFF
read_rnd_buffer_size 262144
relay_log
relay_log_basename /opt/local/var/db/mysql57/254-relay-bin
relay_log_index /opt/local/var/db/mysql57/254-relay-bin.index
relay_log_info_file relay-log.info
relay_log_info_repository FILE
relay_log_purge ON
relay_log_recovery OFF
relay_log_space_limit 0
report_host
report_password
report_port 0
report_user
require_secure_transport OFF
rpl_stop_slave_timeout 31536000
secure_auth ON
secure_file_priv /opt/local/var/db/mysql57-files/
server_id 0
server_id_bits 32
server_uuid ebdb8ee8-be4c-11e6-8ec5-97f60e5fb56e
session_track_gtids OFF
session_track_schema ON
session_track_state_change OFF
session_track_system_variables time_zone,autocommit,character_set_client,character_set_results,character_set_connection
session_track_transaction_info OFF
sha256_password_auto_generate_rsa_keys ON
sha256_password_private_key_path private_key.pem
sha256_password_proxy_users OFF
sha256_password_public_key_path public_key.pem
show_compatibility_56 OFF
show_old_temporals OFF
skip_external_locking ON
skip_name_resolve ON
skip_networking ON
skip_show_database OFF
slave_allow_batching OFF
slave_checkpoint_group 512
slave_checkpoint_period 300
slave_compressed_protocol OFF
slave_exec_mode STRICT
slave_load_tmpdir /var/folders/zz/zyxvpxvq6csfxvn_n000009800002_/T/
slave_max_allowed_packet 1073741824
slave_net_timeout 60
slave_parallel_type DATABASE
slave_parallel_workers 0
slave_pending_jobs_size_max 16777216
slave_preserve_commit_order OFF
slave_rows_search_algorithms TABLE_SCAN,INDEX_SCAN
slave_skip_errors OFF
slave_sql_verify_checksum ON
slave_transaction_retries 10
slave_type_conversions
slow_launch_time 2
slow_query_log OFF
slow_query_log_file /opt/local/var/db/mysql57/254-slow.log
socket /opt/local/var/run/mysql57/mysqld.sock
sort_buffer_size 262144
sql_auto_is_null OFF
sql_big_selects ON
sql_buffer_result OFF
sql_log_off OFF
sql_mode ONLY_FULL_GROUP_BY,STRICT_TRANS_TABLES,NO_ZERO_IN_DATE,NO_ZERO_DATE,ERROR_FOR_DIVISION_BY_ZERO,NO_AUTO_CREATE_USER,NO_ENGINE_SUBSTITUTION
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 ca.pem
ssl_capath
ssl_cert server-cert.pem
ssl_cipher
ssl_crl
ssl_crlpath
ssl_key server-key.pem
stored_program_cache 256
super_read_only OFF
sync_binlog 1
sync_frm ON
sync_master_info 10000
sync_relay_log 10000
sync_relay_log_info 10000
system_time_zone CST
table_definition_cache 1400
table_open_cache 2000
table_open_cache_instances 16
thread_cache_size 10
thread_handling one-thread-per-connection
thread_stack 262144
time_format %H:%i:%s
time_zone SYSTEM
tls_version TLSv1,TLSv1.1,TLSv1.2
tmp_table_size 33554432
tmpdir /var/folders/zz/zyxvpxvq6csfxvn_n000009800002_/T/
transaction_alloc_block_size 8192
transaction_prealloc_size 4096
transaction_write_set_extraction OFF
tx_isolation REPEATABLE-READ
tx_read_only OFF
unique_checks ON
updatable_views_with_limit YES
validate_password_check_user_name OFF
validate_password_dictionary_file
validate_password_length 8
validate_password_mixed_case_count 1
validate_password_number_count 1
validate_password_policy MEDIUM
validate_password_special_char_count 1
version 5.7.17
version_comment Source distribution
version_compile_machine x86_64
version_compile_os osx10.12
wait_timeout 28800
UPDATE 2/15: I doubled wait_timeout to 57600 and connect_timeout to 20 this morning based on some feedback found in other threads. Should I also increase interactive_timeout? Are there any negative effects I should watch out for as a result of such changes?