Single Table Queries Very Slow With Indexes MariaDB

Question

I am trying to tune some slow running queries on MariaDB and have hit a brick wall. I mainly work with Postgres / Oracle and these queries times seem extremely slow to me, but I can't figure out what I'm missing.

The queries in question (see below for examples) are mostly single table queries or with one join / subquery. The table in question has around 19million rows (26.5gb) and has fairly frequent writes.

Table structure and indexes below:

CREATE TABLE products_reviews (
    id bigint(20) NOT NULL AUTO_INCREMENT
,   product_id int(11) NOT NULL DEFAULT 0
,   name varchar(255) NOT NULL DEFAULT ''
,   rate tinyint(4) NOT NULL DEFAULT 0
,   created_at datetime NOT NULL
,   posted_at date NOT NULL
,   site varchar(50) NOT NULL
,   review text NOT NULL
,   details text DEFAULT NULL
,   type smallint(6) NOT NULL DEFAULT 0
,  notify smallint(6) NOT NULL DEFAULT 1
,   notify_daily int(11) NOT NULL DEFAULT 1
,   user_id int(11) DEFAULT NULL
,   updated_at datetime NOT NULL
,   admin_id int(11) DEFAULT NULL
,   status smallint(6) NOT NULL DEFAULT 0
,   comment text NOT NULL
,   notified_at datetime NOT NULL
,   reply tinyint(4) NOT NULL DEFAULT 0
,   syndicate varchar(100) NOT NULL
,   status_user tinyint(4) NOT NULL
,   reviewer_id varchar(100) NOT NULL DEFAULT ''
,  sentiment text DEFAULT NULL
,   sentiment_score float(5,2) NOT NULL DEFAULT 0.00
,   ai text DEFAULT NULL
,   active tinyint(4) NOT NULL DEFAULT 1
,   active_updated_at datetime NOT NULL DEFAULT current_timestamp()
,   review_translate text NOT NULL
,   price float(6,2) NOT NULL
,   tagging text NOT NULL
,   site_id int(11) NOT NULL
,   hash varchar(255) NOT NULL
,   PRIMARY KEY (id)
,   KEY created_at (created_at)
,   KEY posted_at (posted_at)
,   KEY site (site)
,   KEY product_id (product_id)
,   KEY admin_id (admin_id)
,   KEY type (type)
,   KEY notify (notify)
,   KEY active (active)
,   KEY admin_posted (admin_id,posted_at)
,   KEY reviewer_id (reviewer_id)
,   KEY idx_products_reviews_pspth (product_id,site,posted_at,type,hash)
,   KEY idx_products_reviews_pa (product_id,active)
,   KEY idx_products_reviews_product_posted (product_id,posted_at)
,   KEY idx_products_reviews_product_adminid_postedid (product_id,admin_id,posted_at)
,   KEY product_id_2 (product_id,site,active) 
) ENGINE=InnoDB AUTO_INCREMENT=27316062 DEFAULT CHARSET=utf8

Mariadb settings below:

alter_algorithm DEFAULT 
aria_block_size 8192    
aria_checkpoint_interval    30  
aria_checkpoint_log_activity    1048576 
aria_encrypt_tables OFF 
aria_force_start_after_recovery_failures    0   
aria_group_commit   none    
aria_group_commit_interval  0   
aria_log_file_size  1073741824  
aria_log_purge_type immediate   
aria_max_sort_file_size 9223372036853727232 
aria_page_checksum  ON  
aria_pagecache_age_threshold    300 
aria_pagecache_buffer_size  134217728   
aria_pagecache_division_limit   100 
aria_pagecache_file_hash_size   512 
aria_recover_options    BACKUP,QUICK    
aria_repair_threads 1   
aria_sort_buffer_size   268434432   
aria_stats_method   nulls_unequal   
aria_sync_log_dir   NEWFILE 
aria_used_for_temp_tables   ON  
auto_increment_increment    1   
auto_increment_offset   1   
autocommit  ON  
automatic_sp_privileges ON  
back_log    100 
basedir /usr    
big_tables  OFF 
binlog_annotate_row_events  ON  
binlog_cache_size   32768   
binlog_checksum CRC32   
binlog_commit_wait_count    0   
binlog_commit_wait_usec 100000  
binlog_direct_non_transactional_updates OFF 
binlog_file_cache_size  16384   
binlog_format   MIXED   
binlog_optimize_thread_scheduling   ON  
binlog_row_image    FULL    
binlog_stmt_cache_size  32768   
bulk_insert_buffer_size 8388608 
check_constraint_checks ON  
column_compression_threshold    100 
column_compression_zlib_level   6   
column_compression_zlib_strategy    DEFAULT_STRATEGY    
column_compression_zlib_wrap    OFF 
completion_type NO_CHAIN    
concurrent_insert   AUTO    
connect_timeout 10  
core_file   OFF 
date_format %Y-%m-%d    
datetime_format %Y-%m-%d %H:%i:%s   
deadlock_search_depth_long  15  
deadlock_search_depth_short 4   
deadlock_timeout_long   50000000    
deadlock_timeout_short  10000   
debug_no_thread_alarm   OFF 
default_master_connection       
default_regex_flags     
default_storage_engine  InnoDB  
default_tmp_storage_engine  MyISAM  
default_week_format 0   
delay_key_write ON  
delayed_insert_limit    100 
delayed_insert_timeout  300 
delayed_queue_size  1000    
div_precision_increment 4   
encrypt_binlog  OFF 
encrypt_tmp_disk_tables OFF 
encrypt_tmp_files   OFF 
enforce_storage_engine      
eq_range_index_dive_limit   0   
error_count 0   
event_scheduler OFF 
expensive_subquery_limit    100 
expire_logs_days    7   
explicit_defaults_for_timestamp OFF 
external_user       
extra_max_connections   1   
extra_port  0   
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 
group_concat_max_len    1048576 
gtid_binlog_pos     
gtid_binlog_state       
gtid_current_pos        
gtid_domain_id  0   
gtid_ignore_duplicates  OFF 
gtid_pos_auto_engines       
gtid_seq_no 0   
gtid_slave_pos      
gtid_strict_mode    OFF 
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    DISABLED    
have_symlink    YES 
histogram_size  0   
histogram_type  SINGLE_PREC_HB  
host_cache_size 633 
identity    0   
idle_readonly_transaction_timeout   0   
idle_transaction_timeout    0   
idle_write_transaction_timeout  0   
ignore_builtin_innodb   OFF 
ignore_db_dirs      
in_predicate_conversion_threshold   1000    
in_transaction  0   
init_connect        
init_file       
init_slave      
innodb_adaptive_flushing    ON  
innodb_adaptive_flushing_lwm    10.000000   
innodb_adaptive_hash_index  ON  
innodb_adaptive_hash_index_parts    8   
innodb_adaptive_max_sleep_delay 150000  
innodb_autoextend_increment 64  
innodb_autoinc_lock_mode    1   
innodb_background_scrub_data_check_interval 3600    
innodb_background_scrub_data_compressed OFF 
innodb_background_scrub_data_interval   604800  
innodb_background_scrub_data_uncompressed   OFF 
innodb_buf_dump_status_frequency    0   
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    8   
innodb_buffer_pool_load_abort   OFF 
innodb_buffer_pool_load_at_startup  ON  
innodb_buffer_pool_load_now OFF 
innodb_buffer_pool_size 68719476736 
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_algorithm    zlib    
innodb_compression_default  OFF 
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_encryption_key_id    1   
innodb_default_row_format   dynamic 
innodb_disable_sort_file_cache  OFF 
innodb_disallow_writes  OFF 
innodb_doublewrite  ON  
innodb_encrypt_log  OFF 
innodb_encrypt_tables   OFF 
innodb_encrypt_temporary_tables OFF 
innodb_encryption_rotate_key_age    1   
innodb_encryption_rotation_iops 100 
innodb_encryption_threads   0   
innodb_fast_shutdown    1   
innodb_fatal_semaphore_wait_threshold   600 
innodb_file_format      
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 fsync   

innodb_flush_neighbors  1   
innodb_flush_sync   ON  
innodb_flushing_avg_loops   30  
innodb_force_load_corrupted OFF 
innodb_force_primary_key    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_idle_flush_pct   100 
innodb_immediate_scrub_data_uncompressed    OFF 
innodb_io_capacity  1000    
innodb_io_capacity_max  2000    
innodb_large_prefix     
innodb_lock_schedule_algorithm  fcfs    
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    50331648    
innodb_log_files_in_group   2   
innodb_log_group_home_dir   ./  
innodb_log_optimize_ddl ON  
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    10485760    
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   4096    
innodb_optimize_fulltext_only   OFF 
innodb_page_cleaners    4   
innodb_page_size    16384   
innodb_prefix_index_cluster_optimization    OFF 
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_scrub_log    OFF 
innodb_scrub_log_speed  256 
innodb_sort_buffer_size 1048576 
innodb_spin_wait_delay  4   
innodb_stats_auto_recalc    ON  
innodb_stats_include_delete_marked  OFF 
innodb_stats_method nulls_equal 
innodb_stats_modified_counter   0   
innodb_stats_on_metadata    OFF 
innodb_stats_persistent ON  
innodb_stats_persistent_sample_pages    20  
innodb_stats_sample_pages   8   
innodb_stats_traditional    ON  
innodb_stats_transient_sample_pages 8   
innodb_status_output    OFF 
innodb_status_output_locks  OFF 
innodb_strict_mode  OFF 
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_atomic_writes    ON  
innodb_use_native_aio   ON  
innodb_version  10.3.21 
innodb_write_io_threads 4   
insert_id   0   
interactive_timeout 3600    
join_buffer_size    1048576 
join_buffer_space_limit 2097152 
join_cache_level    2   

keep_files_on_create    OFF 
key_buffer_size 67108864    
key_cache_age_threshold 300 
key_cache_block_size    1024    
key_cache_division_limit    100 
key_cache_file_hash_size    512 
key_cache_segments  0   
large_files_support ON  
large_page_size 0   
large_pages OFF 
last_gtid       
last_insert_id  0   
lc_messages en_US   
lc_messages_dir     
lc_time_names   en_US   
license GPL 
local_infile    ON  
lock_wait_timeout   86400   
locked_in_memory    OFF 
log_bin OFF 
log_bin_basename        
log_bin_compress    OFF 
log_bin_compress_min_len    256 
log_bin_index       
log_bin_trust_function_creators OFF 
log_disabled_statements sp  
log_error   /var/log/mariadb/mariadb.log    
log_output  FILE    
log_queries_not_using_indexes   OFF 
log_slave_updates   OFF 
log_slow_admin_statements   ON  
log_slow_disabled_statements    sp  
log_slow_filter admin,filesort,filesort_on_disk,filesort_priority_queue,full_join,full_scan,query_cache,query_cache_miss,tmp_table,tmp_table_on_disk    
log_slow_rate_limit 1   
log_slow_slave_statements   ON  
log_slow_verbosity      
log_tc_size 24576   
log_warnings    2   
long_query_time 1.000000    
low_priority_updates    OFF 
lower_case_file_system  OFF 
lower_case_table_names  0   
master_verify_checksum  OFF 
max_allowed_packet  67108864    
max_binlog_cache_size   18446744073709547520    
max_binlog_size 1073741824  
max_binlog_stmt_cache_size  18446744073709547520    
max_connect_errors  10000   
max_connections 600 
max_delayed_threads 20  
max_digest_length   1024    
max_error_count 64  
max_heap_table_size 67108864    
max_insert_delayed_threads  20  
max_join_size   18446744073709551615    
max_length_for_sort_data    1024    
max_long_data_size  67108864    
max_prepared_stmt_count 16382   
max_recursive_iterations    4294967295  
max_relay_log_size  1073741824  
max_seeks_for_key   4294967295  
max_session_mem_used    9223372036854775807 
max_sort_length 1024    
max_sp_recursion_depth  0   
max_statement_time  0.000000    
max_tmp_tables  32  
max_user_connections    0   
max_write_lock_count    4294967295  
metadata_locks_cache_size   1024    
metadata_locks_hash_instances   8   
min_examined_row_limit  0   
mrr_buffer_size 262144  
multi_range_count   256 
myisam_block_size   1024    
myisam_data_pointer_size    6   
myisam_max_sort_file_size   9223372036853727232 
myisam_mmap_size    18446744073709551615    
myisam_recover_options  BACKUP,QUICK    
myisam_repair_threads   1   
myisam_sort_buffer_size 134217728   
myisam_stats_method NULLS_UNEQUAL   
myisam_use_mmap OFF 
mysql56_temporal_format ON  
net_buffer_length   16384   
net_read_timeout    30  
net_retry_count 10  
net_write_timeout   60  
open_files_limit    65535   
optimizer_prune_level   1   
optimizer_search_depth  62  
optimizer_selectivity_sampling_limit    100 
optimizer_switch    index_merge=off,index_merge_union=on,index_merge_sort_union=on,index_merge_intersection=on,index_merge_sort_intersection=off,engine_condition_pushdown=off,index_condition_pushdown=on,derived_merge=on,derived_with_keys=on,firstmatch=on,loosescan=on,materialization=on,in_to_exists=on,semijoin=on,partial_match_rowid_merge=on,partial_match_table_scan=on,subquery_cache=on,mrr=off,mrr_cost_based=off,mrr_sort_keys=off,outer_join_with_cache=on,semijoin_with_cache=on,join_cache_incremental=on,join_cache_hashed=on,join_cache_bka=on,optimize_join_buffer_size=off,table_elimination=on,extended_keys=on,exists_to_in=on,orderby_uses_equalities=on,condition_pushdown_for_derived=on,split_materialized=on  
optimizer_use_condition_selectivity 1   
performance_schema  OFF 
performance_schema_accounts_size    -1  
performance_schema_digests_size -1  

performance_schema_events_stages_history_long_size  -1  
performance_schema_events_stages_history_size   -1  
performance_schema_events_statements_history_long_size  -1  
performance_schema_events_statements_history_size   -1  
performance_schema_events_waits_history_long_size   -1  
performance_schema_events_waits_history_size    -1  
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 50  
performance_schema_max_file_handles 32768   
performance_schema_max_file_instances   -1  
performance_schema_max_mutex_classes    200 
performance_schema_max_mutex_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_stage_classes    160 
performance_schema_max_statement_classes    200 
performance_schema_max_table_handles    -1  
performance_schema_max_table_instances  -1  
performance_schema_max_thread_classes   50  
performance_schema_max_thread_instances -1  
performance_schema_session_connect_attrs_size   -1  
performance_schema_setup_actors_size    100 
performance_schema_setup_objects_size   100 
performance_schema_users_size   -1  
pid_file    /var/run/mariadb/mariadb.pid    
plugin_dir  /usr/lib64/mysql/plugin/    
plugin_maturity gamma   
port    3306    
preload_buffer_size 32768   
profiling   OFF 
profiling_history_size  15  
progress_report_time    5   
protocol_version    10  
proxy_protocol_networks     
proxy_user      
pseudo_slave_mode   OFF 
pseudo_thread_id    1852681 
query_alloc_block_size  16384   
query_cache_limit   1048576 
query_cache_min_res_unit    4096    
query_cache_size    1048576 
query_cache_strip_comments  OFF 
query_cache_type    OFF 
query_cache_wlock_invalidate    OFF 
query_prealloc_size 24576   
rand_seed1  93838501    
rand_seed2  36662033    
range_alloc_block_size  4096    
read_binlog_speed_limit 0   
read_buffer_size    1048576 
read_only   OFF 
read_rnd_buffer_size    1048576 
relay_log       
relay_log_basename      
relay_log_index     
relay_log_info_file relay-log.info  
relay_log_purge ON  
relay_log_recovery  OFF 
relay_log_space_limit   17179869184 
replicate_annotate_row_events   ON  
replicate_do_db     
replicate_do_table      
replicate_events_marked_for_skip    REPLICATE   
replicate_ignore_db     
replicate_ignore_table      
replicate_wild_do_table     
replicate_wild_ignore_table     
report_host     
report_password     
report_port 3306    
report_user     
rowid_merge_buff_size   8388608 
secure_auth ON  
secure_file_priv        
secure_timestamp    NO  
server_id   1   
session_track_schema    ON  
session_track_state_change  OFF 
session_track_system_variables  autocommit,character_set_client,character_set_connection,character_set_results,time_zone    
session_track_transaction_info  OFF 
skip_external_locking   ON  
skip_name_resolve   ON  
skip_networking OFF 
skip_parallel_replication   OFF 
skip_replication    OFF 
skip_show_database  OFF 

slave_compressed_protocol   OFF 
slave_ddl_exec_mode IDEMPOTENT  
slave_domain_parallel_threads   0   
slave_exec_mode STRICT  
slave_load_tmpdir   /san/svc-fs/mysqltmp    
slave_max_allowed_packet    1073741824  
slave_net_timeout   60  
slave_parallel_max_queued   131072  
slave_parallel_mode conservative    
slave_parallel_threads  0   
slave_parallel_workers  0   
slave_run_triggers_for_rbr  NO  
slave_skip_errors   OFF 
slave_sql_verify_checksum   ON  
slave_transaction_retries   10  
slave_transaction_retry_errors  1213,1205   
slave_transaction_retry_interval    0   
slave_type_conversions      
slow_launch_time    2   
slow_query_log  ON  
slow_query_log_file /san/svc-fs/mysqllogs/slow-log  
socket  /san/svc-fs/mysql/mysql.sock    
sort_buffer_size    1048576 
sql_auto_is_null    OFF 
sql_big_selects ON  
sql_buffer_result   OFF 
sql_log_bin ON  
sql_log_off OFF 
sql_mode    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      
ssl_capath      
ssl_cert        
ssl_cipher      
ssl_crl     
ssl_crlpath     
ssl_key     
standard_compliant_cte  ON  
storage_engine  InnoDB  
stored_program_cache    256 
strict_password_validation  ON  
sync_binlog 0   
sync_frm    ON  
sync_master_info    10000   
sync_relay_log  10000   
sync_relay_log_info 10000   
system_time_zone    CST 
system_versioning_alter_history ERROR   
system_versioning_asof  DEFAULT 
table_definition_cache  4096    
table_open_cache    4096    
table_open_cache_instances  8   
tcp_keepalive_interval  0   
tcp_keepalive_probes    0   
tcp_keepalive_time  0   
thread_cache_size   16  
thread_concurrency  10  
thread_handling one-thread-per-connection   
thread_pool_idle_timeout    60  
thread_pool_max_threads 65536   
thread_pool_oversubscribe   3   
thread_pool_prio_kickup_timer   1000    
thread_pool_priority    auto    
thread_pool_size    16  
thread_pool_stall_limit 500 
thread_stack    299008  
time_format %H:%i:%s    
time_zone   SYSTEM  
timed_mutexes   OFF 
timestamp   1644789513.087889   
tmp_disk_table_size 18446744073709551615    
tmp_memory_table_size   33554432    
tmp_table_size  33554432    
tmpdir  /san/svc-fs/mysqltmp    
transaction_alloc_block_size    8192    
transaction_prealloc_size   4096    
tx_isolation    REPEATABLE-READ 
tx_read_only    OFF 
unique_checks   ON  
updatable_views_with_limit  YES 
use_stat_tables NEVER   
userstat    OFF 
version 10.3.21-MariaDB-log 
version_comment MariaDB Server  
version_compile_machine x86_64  
version_compile_os  Linux   
version_malloc_library  jemalloc 3.6.0-0-g46c0af68bd248b04df75e4f92d5fb804c3d75340  
version_source_revision e5e5877740f248de848219ee3a1d2881cd5c5b82    
version_ssl_library OpenSSL 1.0.2k-fips  26 Jan 2017    
wait_timeout    600 
warning_count   0   
wsrep_osu_method    TOI 
wsrep_auto_increment_control    ON  
wsrep_causal_reads  OFF 
wsrep_certification_rules   strict  

wsrep_certify_nonpk ON  
wsrep_cluster_address       
wsrep_cluster_name  my_wsrep_cluster    
wsrep_convert_lock_to_trx   OFF 
wsrep_data_home_dir /san/svc-fs/mysql/  
wsrep_dbug_option       
wsrep_debug OFF 
wsrep_desync    OFF 
wsrep_dirty_reads   OFF 
wsrep_drupal_282555_workaround  OFF 
wsrep_forced_binlog_format  NONE    
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wsrep_gtid_mode OFF 
wsrep_load_data_splitting   ON  
wsrep_log_conflicts OFF 
wsrep_max_ws_rows   0   
wsrep_max_ws_size   2147483647  
wsrep_mysql_replication_bundle  0   
wsrep_node_address      
wsrep_node_incoming_address AUTO    
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wsrep_on    OFF 
wsrep_patch_version wsrep_25.24 
wsrep_provider  none    
wsrep_provider_options      
wsrep_recover   OFF 
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wsrep_replicate_myisam  OFF 
wsrep_restart_slave OFF 
wsrep_retry_autocommit  1   
wsrep_slave_fk_checks   ON  
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wsrep_slave_threads 1   
wsrep_sst_auth      
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The queries filters can be selected on the front end by a user so the where clause can vary a bit. They will all contain a product_id at least. The speed to read from disk seems absurdly slow for the number of rows being fetched.

Example queries: This one takes 400seconds to return

Edit - Below query is in an incorrect format which must have happened when creating the post. Original is below

SELECT SQL_NO_CACHE 
       pr.rate as star, pr.product_id, pr.site, COUNT(pr.id) AS count 
  FROM products_reviews pr
   JOIN products p ON p.id = pr.product_id
   AND pr.active > 0 
   AND pr.posted_at >= '2020-10-26' 
   AND pr.posted_at <= '2022-01-24 23:59' 
   AND pr.admin_id = 3598 
 GROUP BY pr.rate, pr.product_id, pr.site;

SELECT rate as star, product_id, site, COUNT(id) AS count 
  FROM products_reviews 
 WHERE product_id IN (SELECT id FROM products WHERE admin_id = 3598) 
   AND active >0 AND posted_at >= '2020-10-26' 
   AND posted_at <= '2022-01-24 23:59'
   AND admin_id = 3598
 GROUP BY rate, product_id, site

Explain plan

{
 "query_block": {
   "select_id": 1,
   "filesort": {
     "sort_key": "products_reviews.rate, products_reviews.product_id, products_reviews.site",
     "temporary_table": {
       "table": {
         "table_name": "products_reviews",
         "access_type": "range",
         "possible_keys": [
           "posted_at",
           "product_id",
           "admin_id",
           "active",
           "admin_posted",
           "idx_products_reviews_pspth",
           "idx_products_reviews_pa",
           "idx_products_reviews_product_posted",
           "idx_products_reviews_product_adminid_postedid",
           "product_id_2",
           "idx_products_aaprps_covering",
           "idx_products_aprps_covering_t"
         ],
         "key": "idx_products_aaprps_covering",
         "key_length": "6",
         "used_key_parts": ["admin_id", "active"],
         "rows": 1826162,
         "filtered": 100,
         "attached_condition": "products_reviews.admin_id = 3598 and products_reviews.active > 0 and products_reviews.posted_at >= '2020-10-26' and products_reviews.posted_at <= '2022-01-24 23:59'",
         "using_index": true
       },
       "table": {
         "table_name": "products",
         "access_type": "eq_ref",
         "possible_keys": ["PRIMARY", "id", "admin_id"],
         "key": "PRIMARY",
         "key_length": "8",
         "used_key_parts": ["id"],
         "ref": ["metabase.products_reviews.product_id"],
         "rows": 1,
         "filtered": 100,
         "attached_condition": "products.admin_id = 3598 and products_reviews.product_id = products.`id`"
       }
     }
   }
 }
}

I ran profiling on the transaction and the whole time is spent on "Sending Data".

Here is a second query, this one takes around 32 seconds.

SELECT site, MIN(posted_at) as posted_at, AVG(IF(rate>0, rate, NULL)) as rate, COUNT(IF(type=0, 1, NULL)) as count, COUNT(IF(type=0 AND syndicate='', 1, NULL)) as count_ns, AVG(IF(rate>0 AND syndicate='', rate, NULL)) as rate_ns, COUNT(IF(type=1, 1, NULL)) as count_qe 
  FROM products_reviews 
 WHERE product_id = '24828' 
   AND active >0 
 GROUP BY site

Explain Plan

{
 "query_block": {
   "select_id": 1,
   "table": {
     "table_name": "products_reviews",
     "access_type": "ref",
     "possible_keys": [
       "product_id",
       "active",
       "idx_products_reviews_pspth",
       "idx_products_reviews_pa",
       "idx_products_reviews_product_posted",
       "idx_products_reviews_product_adminid_postedid",
       "product_id_2"
     ],
     "key": "product_id_2",
     "key_length": "4",
     "used_key_parts": ["product_id"],
     "ref": ["const"],
     "rows": 6575,
     "filtered": 100,
     "attached_condition": "products_reviews.product_id <=> '24828' and products_reviews.active > 0"
   }
 }
{
 "query_block": {
   "select_id": 1,
   "table": {
     "table_name": "products_reviews",
     "access_type": "ref",
     "possible_keys": [
       "product_id",
       "active",
       "idx_products_reviews_pspth",
       "idx_products_reviews_pa",
       "idx_products_reviews_product_posted",
       "idx_products_reviews_product_adminid_postedid",
       "product_id_2"
     ],
     "key": "product_id_2",
     "key_length": "4",
     "used_key_parts": ["product_id"],
     "ref": ["const"],
     "rows": 6575,
     "filtered": 100,
     "attached_condition": "products_reviews.product_id <=> '24828' and products_reviews.active > 0"
   }
 }
}

Possibly partially related to cardinality. Here's a count of rows, distinct product_id and distinct posted_at.

count(*) 19128090
count(distinct(product_id)) 28821
count(distinct(posted_at)) 7551

The server has 96gb RAM and a 480GB SATA SSD. The buffer pool settings look well optimized to me. I tried increasing innodb_io_capacity but that had a negative impact.

If there is nothing I can do to speed up the queries with regards query tuning or parameter tuning, I wondered about keeping the table in memory at all times. They seem to get flushed at least once a day (probably around the time backups are taken). Would it be sensible to have a job that runs once every couple of hours to select * from the table?

Many thanks.

Answer 1

`products is only sort of used. If you don't really need it, get rid of it. I see two things that can matter:

• If there is no matching row from products the JOIN will avoid including it.
• If there are multiple rows in products, then the COUNT will increase.

Replace

JOIN products p ON p.id = pr.product_id
 AND

with

WHERE

As a rule:

• Use ON to specify how the tables are related.
• Use WHERE to specify which rows to keep.

Another INDEX tip: When you need INDEX(a,b), you can do without INDEX(a). I am thinking of (admin_id, posted_at)

If active is only "0" or "1", then use AND active = 1, plus change to INDEX(admin_id, active, posted_at)

"indexes could only contain one equality operator" -- The rule is more like "Indexes should contain only one range operator, and it needs to be last". (Note: "covering" is a deliberate exception.)

(I agree that the 'covering' index may help, but I generally avoid indexes with lots of columns.)

I have the master of that MariaDB link (that RLOG mentioned); it has been updated a few times here: http://mysql.rjweb.org/doc.php/index_cookbook_mysql

Answer 2

It's a good question you ask. My answer has a few dimensions.

Server provisioning: Your machine is adequate, and possibly overprovisioned. You have allocated 2/3 of your server's RAM to your 64GiB InnoDB buffer pool (innodb_buffer_pool_size) and that's probably enough to hold your tables. You could allocate another 8 - 12 GiB to it and still have RAM left over for your server's other functions. But buffer pool size is almost certainly not your issue.

Many indexes: You have quite a few single-column indexes. Are you sure they are all needed? Generally speaking, we create indexes to support particular query patterns, not because they might be helpful someday. If you can drop some of your indexes, do so. And, indexes slow down INSERTs and UPDATEs because both the table data and indexes are affected. Which brings us to ...

Frequent updates: It's possible that your update operations slow down the reporting-style queries you showed us in your question because the server is struggling to give consistent results (using locks) as updates happen. Try giving this SQL statement right before your too-slow query.

   SET TRANSACTION ISOLATION LEVEL READ UNCOMMITTED;

This causes a "dirty read". It cuts down on locking, but gives you the chance you'll get an older version of rows that are being actively updated. That's usually no problem for reporting-style queries. Try it and see how much it helps.

Equality and range filters, covering BTREE indexes. Consider your first query, repeated here:

SELECT SQL_NO_CACHE 
       pr.rate as star, pr.product_id, pr.site, COUNT(pr.id) AS count 
  FROM products_reviews pr
  JOIN products p ON p.id = pr.product_id
   AND pr.active > 0 
   AND pr.posted_at >= '2020-10-26' 
   AND pr.posted_at <= '2022-01-24 23:59' 
   AND pr.admin_id = 3598 
 GROUP BY pr.rate, pr.product_id, pr.site;

You filter product_reviews on admin_id for equality, then active and posted at for ranges, then you look up rows in products, then group by rate, product_id, and site.

Try using this so-called covering index.

CREATE INDEX rate_product_site_rollup ON products_review
             (admin_id, posted_at, active, rate, product_id, site);

It contains the data your query needs from the products_review table. To satisfy the query, the database can random-access the index to the first eligible row (admin_id = nnnn and the first eligible posted_at row. It can then scan the index sequentially to filter out active <= 0 rows. Finally, your GROUP BY columns are there already sorted in an order suitable for quick grouping.

You might consider a similar covering index for your second query.

(Some makes and versions of database servers allow INCLUDE(col, col, col) clauses in index declarations, but not MariaDB / MySQL. INCLUDE is very useful for covering indexes, but including the columns in the index works too.)

More than one range filter: BTREE indexes do their fastest work when you only have one range filter in your query. If your business rules allowed you to filter on pr.active = 1 then this index would satisfy your query even faster.

CREATE INDEX rate_product_site_rollup ON products_review
             (admin_id, active, posted_at, rate, product_id, site);

Extraneous JOIN: You JOIN to your products table, but don't use any columns from it. So the JOIN serves only one purpose: to exclude reviews that have no matching product. Is this step necessary?

Note: pr.posted_at < '2022-01-24' + INTERVAL 1 DAY, with <, is a bit more reliable on the almost-midnight edge case than pr.posted_at <= '2022-01-24 23:59'