En complément de l'article Tentative de création d'un analogue d'ASH pour PostgreSQL .

Défi

Vous devez lier l'historique des vues pg_stat_statemenets, pg_stat_activity. Par conséquent, en utilisant l'historique des plans d'exécution de la table de service log_query, vous pouvez obtenir de nombreuses informations utiles à utiliser pour résoudre les incidents de performances et optimiser les requêtes.

Avertissement
En raison de la nouveauté du sujet et de la période de test incomplète, l'article peut contenir des erreurs. La critique et les commentaires sont fortement encouragés et attendus.

Entrer les données

Table History_pg_stat_activity

--ACTIVITY_HIST.HISTORY_PG_STAT_ACTIVITY DROP TABLE IF EXISTS activity_hist.history_pg_stat_activity; CREATE TABLE activity_hist.history_pg_stat_activity ( timepoint timestamp without time zone , datid oid , datname name , pid integer, usesysid oid , usename name , application_name text , client_addr inet , client_hostname text , client_port integer, backend_start timestamp without time zone , xact_start timestamp without time zone , query_start timestamp without time zone , state_change timestamp without time zone , wait_event_type text , wait_event text , state text , backend_xid xid , backend_xmin xid , query text , backend_type text , queryid bigint );

Table Pg_stat_db_queries

 CREATE TABLE pg_stat_db_queries ( database_id integer , queryid bigint , query text , max_time double precision );(

Vue matérialisée de mvw_pg_stat_queries

 CREATE MATERIALIZED VIEW public.mvw_pg_stat_queries AS SELECT t.queryid, t.max_time, t.query FROM public.dblink('LINK1'::text, 'SELECT queryid , max_time , query FROM pg_stat_statements WHERE dbid=(SELECT oid FROM pg_database WHERE datname=current_database() ) AND max_time >= 0 '::text) t(queryid bigint, max_time double precision, query text) WITH NO DATA;

Table log_query

 CREATE TABLE log_query ( id integer , queryid bigint , query_md5hash text , database_id integer , timepoint timestamp without time zone , query text , explained_plan text[] , plan_md5hash text , explained_plan_wo_costs text[] , plan_hash_value text , ip text, port text , pid integer );

Algorithme général

Actualiser la table pg_stat_db_queries

Actualiser la vue des matériaux mvw_pg_stat_queries

 CREATE OR REPLACE FUNCTION refresh_pg_stat_queries_list( database_id int) RETURNS BOOLEAN AS $$ DECLARE result BOOLEAN ; database_rec record ; BEGIN SELECT * INTO database_rec FROM endpoint e JOIN database d ON e.id = d.endpoint_id WHERE d.id = database_id ; IF NOT database_rec.is_need_monitoring THEN RAISE NOTICE 'NO NEED MONITORING FOR database_id=%',database_id; return TRUE ; END IF ; EXECUTE 'SELECT dblink_connect(''LINK1'',''host='||database_rec.host||' port=5432 dbname='||database_rec.name|| ' user='||database_rec.s_name||' password='||database_rec.s_pass|| ' '')'; REFRESH MATERIALIZED VIEW mvw_pg_stat_queries ; PERFORM dblink_disconnect('LINK1'); RETURN result; END $$ LANGUAGE plpgsql;

Remplissez la table pg_stat_db_queries

 CREATE OR REPLACE FUNCTION refresh_pg_stat_db_queries( ) RETURNS BOOLEAN AS $$ DECLARE result BOOLEAN ; database_rec record ; pg_stat_rec record ; BEGIN TRUNCATE pg_stat_db_queries; FOR database_rec IN SELECT * FROM database d LOOP IF NOT database_rec.is_need_monitoring THEN RAISE NOTICE 'NO NEED MONITORING FOR database_id=%',database_rec.id; CONTINUE ; END IF ; PERFORM refresh_pg_stat_queries_list( database_rec.id ) ; FOR pg_stat_rec IN SELECT * FROM mvw_pg_stat_queries LOOP INSERT INTO pg_stat_db_queries ( database_id , queryid , query , max_time ) VALUES ( database_rec.id , pg_stat_rec.queryid , pg_stat_rec.query , pg_stat_rec.max_time); END LOOP; END LOOP; RETURN TRUE; END $$ LANGUAGE plpgsql;

Par conséquent, la table contient des textes de requête normalisés, queryid, le temps d'exécution maximal de la requête au moment actuel (utilisé pour la surveillance).

Remplir log_query et former un historique des plans d'exécution.

Le texte de la demande réelle est extrait du fichier journal. Fichier journal de l'hôte cible vers l'hôte de surveillance en plusieurs parties, script bash, cron. Pour économiser de l'espace et en raison de la trivialité de la tâche de copier un morceau d'un fichier texte d'hôte en hôte, le script n'est pas fourni.

Analyser un fichier journal et extraire le texte de la requête

 #!/bin/bash ######################################################### # upload_log_query.sh # Upload table table from dowloaded aws file # version 12.0 ########################################################### echo 'TIMESTAMP:'$(date +%c)' Upload log_query table ' source_file=$1 echo 'source_file='$source_file database_id=$2 echo 'database_id='$database_id database_name=$3 echo 'database_name='$database_name beginer=' ' first_line='1' let "line_count=0" sql_line=' ' sql_flag=' ' space=' ' cat $source_file | while read line do #first line will be passed if [[ $line_count == '0' ]]; then let "line_count++" continue fi line="$space$line" #echo 'line='$line if [[ $first_line == "1" ]]; then beginer=`echo $line | awk -F" " '{ print $1}' ` first_line='0' fi current_beginer=`echo $line | awk -F" " '{ print $1}' ` #echo 'current_beginer='$current_beginer #echo 'beginer='$beginer if [[ $current_beginer == $beginer ]]; then if [[ $sql_flag == '1' ]]; then sql_flag='0' #echo 'TIMESTAMP:'$(date +%c)' Upload log_query table : SQL STATEMENT ='"$sql_line" log_date=`echo $sql_line | awk -F" " '{ print $1}' ` #echo 'log_date='$log_date log_time=`echo $sql_line | awk -F" " '{ print $2}' ` #echo 'log_time='$log_time duration=`echo $sql_line | awk -F" " '{ print $5}' ` #echo 'duration='$duration connect=`echo $sql_line | awk -F" " '{ print $3}' ` userdb=`echo $connect | awk -F":" '{ print $3}' ` userdb2=$userdb'@' db_port_log=`echo $connect | awk -F"@" '{ print $2}' ` log_database_name=`echo $db_port_log | awk -F":" '{ print $1}' ` #echo 'connect='$connect #echo 'userdb='$userdb #echo 'userdb2='$userdb2 #echo 'db_port_log='$db_port_log #echo 'log_database_name='$log_database_name if [[ "$log_database_name" != "$database_name" ]]; then echo '*** database_name '$log_database_name' from log is not equal '$database_name' CONTINUE ' continue; fi #replace ' to '' sql_modline=`echo "$sql_line" | sed 's/'\''/'\'''\''/g'` sql_line=' ' #echo '*********************************log_query start' #echo 'pid_str='$pid_str #echo 'ip_port='$ip_port #echo 'database_id='$database_id #echo 'log_date='$log_date #echo 'log_time='$log_time #echo 'duration='$duration #echo 'sql_modline='$sql_modline if ! psql -U monitor -d monitor -v ON_ERROR_STOP=1 -A -t -q -c "select log_query( '$pid_str' , '$ip_port' , $database_id , '$log_date' , '$log_time' , '$duration' , '$sql_modline' )" then echo 'FATAL_ERROR - log_query ' exit 1 fi #echo '**********************************log_query finish' fi #if [[ $sql_flag == '1' ]]; then let "line_count=line_count+1" #echo 'line_count= '$line_count #echo $line #check=`echo $line | awk -F" " '{ print $8}' ` #check_sql=${check^^} #echo 'check_sql='$check_sql if [[ ${line^^} =~ "SELECT" ]]; then if [[ $line =~ "duration:" ]]; then test_statement=`echo $line | awk -F" " '{ print $8}'` is_select=${test_statement^^} #echo 'test_statement='$test_statement #echo 'is_select='$is_select if [[ $is_select == 'SELECT' ]]; then sql_flag='1' sql_line="$sql_line$line" ip_port=`echo $sql_line | awk -F":" '{ print $4}' ` pid_str=`echo $sql_line | awk -F":" '{ print $6}' ` fi fi fi else #echo $line #echo 'sql_flag ='$sql_flag if [[ $sql_flag == '1' ]]; then sql_line="$sql_line$line" fi fi #if [[ $current_beginer == $beginer ]]; then done

Remplissage de la table Log_query

 --log_query.sql --insert new query into log_query table CREATE OR REPLACE FUNCTION log_query( pid_str text , ip_port text ,log_database_id integer , log_date text , log_time text , duration text , sql_line text ) RETURNS boolean AS $$ DECLARE result boolean ; log_timepoint timestamp without time zone ; log_duration double precision ; pos integer ; log_query text ; activity_string text ; log_md5hash text ; log_explain_plan text[] ; log_planhash text ; log_plan_wo_costs text[] ; database_rec record ; pg_stat_query text ; test_log_query text ; metric_rec record; log_query_rec record; found_flag boolean; pg_stat_history_rec record ; port_start integer ; port_end integer ; client_ip text ; client_port text ; log_queryid bigint ; log_query_text text ; pg_stat_query_text text ; current_pid_str text ; current_pid integer; pid_start_pos integer ; pid_finish_pos integer ; BEGIN result = TRUE ; IF ip_port != '[local]' THEN port_start = position('(' in ip_port); port_end = position(')' in ip_port); client_ip = substring( ip_port from 1 for port_start-1 ); client_port = substring( ip_port from port_start+1 for port_end-port_start-1 ); ELSE client_ip = 'local'; client_port = 'local'; END IF; pid_start_pos = position('[' in pid_str); pid_finish_pos = position(']' in pid_str); current_pid_str=substring( pid_str from 2 for pid_finish_pos - pid_start_pos -1 ); current_pid = to_number(current_pid_str , '999999999999'); SELECT e.host , d.name , d.owner_pwd , d.owner_user INTO database_rec FROM database d JOIN endpoint e ON e.id = d.endpoint_id WHERE d.id = log_database_id ; log_timepoint = to_timestamp(log_date||' '||log_time,'YYYY-MM-DD HH24-MI-SS'); log_duration = duration::double precision ; pos = position ('SELECT' in UPPER(sql_line) ); log_query = substring( sql_line from pos for LENGTH(sql_line)); log_query = regexp_replace(log_query,' +',' ','g'); log_query = regexp_replace(log_query,';+','','g'); log_query = trim(trailing ' ' from log_query); log_md5hash = md5( log_query::text ); --Explain execution plan-- EXECUTE 'SELECT dblink_connect(''LINK1'',''host='||database_rec.host||' port=5432 dbname='||database_rec.name||' user='||database_rec.owner_user||' password='||database_rec.owner_pwd||' '')'; log_explain_plan = ARRAY ( SELECT * FROM dblink('LINK1', 'EXPLAIN '||log_query ) AS t (plan text) ); log_plan_wo_costs = ARRAY ( SELECT * FROM dblink('LINK1', 'EXPLAIN ( COSTS FALSE ) '||log_query ) AS t (plan text) ); PERFORM dblink_disconnect('LINK1'); -------------------------- BEGIN INSERT INTO log_query ( query_md5hash , database_id , timepoint , duration , query , explained_plan , plan_md5hash , explained_plan_wo_costs , plan_hash_value , ip , port , pid ) VALUES ( log_md5hash , log_database_id , log_timepoint , log_duration , log_query , log_explain_plan , md5(log_explain_plan::text) , log_plan_wo_costs , md5(log_plan_wo_costs::text), client_ip , client_port , current_pid ); activity_string = 'New query has logged '|| ' database_id = '|| log_database_id || ' query_md5hash='||log_md5hash|| ' , timepoint = '||to_char(log_timepoint,'YYYYMMDD HH24:MI:SS'); PERFORM pg_log( log_database_id , 'log_query' , activity_string); EXCEPTION WHEN unique_violation THEN activity_string = 'EXCEPTION *** query already has logged '|| ' database_id = '|| log_database_id || ' query_md5hash='||log_md5hash|| ' , timepoint = '||to_char(log_timepoint,'YYYYMMDD HH24:MI:SS'); PERFORM pg_log( log_database_id , 'log_query' , activity_string); END; SELECT queryid INTO log_queryid FROM log_query WHERE query_md5hash = log_md5hash AND timepoint = log_timepoint; IF log_queryid IS NOT NULL THEN RETURN result; END IF; ------------------------------------------------ SELECT * INTO log_query_rec FROM log_query WHERE query_md5hash = log_md5hash AND timepoint = log_timepoint ; log_query_rec.query=regexp_replace(log_query_rec.query,';+','','g'); FOR pg_stat_history_rec IN SELECT queryid , query FROM pg_stat_db_queries WHERE database_id = log_database_id AND queryid is not null LOOP pg_stat_query = pg_stat_history_rec.query ; pg_stat_query=regexp_replace(pg_stat_query,'\n+',' ','g'); pg_stat_query=regexp_replace(pg_stat_query,'\t+',' ','g'); pg_stat_query=regexp_replace(pg_stat_query,' +',' ','g'); pg_stat_query=regexp_replace(pg_stat_query,'\$.','%','g'); log_query_text = trim(trailing ' ' from log_query_rec.query); pg_stat_query_text = pg_stat_query; IF (log_query_text LIKE pg_stat_query_text) THEN found_flag = TRUE ; ELSE found_flag = FALSE ; END IF; IF found_flag THEN UPDATE log_query SET queryid = pg_stat_history_rec.queryid WHERE query_md5hash = log_md5hash AND timepoint = log_timepoint ; activity_string = ' updated queryid = '||pg_stat_history_rec.queryid|| ' for log_query with id = '||log_query_rec.id; EXIT ; END IF ; END LOOP ; RETURN result ; END $$ LANGUAGE plpgsql;

Par conséquent, le tableau contient le texte de la demande réelle, les plans d'exécution, la valeur de hachage du plan d'exécution, la valeur de hachage du texte de la demande.

Remplissez la valeur queryid dans la table history_pg_stat_activity

update_history_pg_stat_activity_by_queryid.sql

 --update_history_pg_stat_activity_by_queryid.sql CREATE OR REPLACE FUNCTION update_history_pg_stat_activity_by_queryid() RETURNS boolean AS $$ DECLARE result boolean ; history_pg_stat_activity_rec record ; pg_stat_query text ; pg_stat_query_text text ; pg_stat_history_rec record; found_flag boolean; history_pg_stat_activity_query text ; query_text text ; activity_string text ; BEGIN RAISE NOTICE '***update_history_pg_stat_activity_by_queryid'; result = TRUE ; FOR history_pg_stat_activity_rec IN SELECT DISTINCT(query) AS query FROM activity_hist.history_pg_stat_activity WHERE queryid IS NULL LOOP history_pg_stat_activity_query = regexp_replace(history_pg_stat_activity_rec.query,'\n+',' ','g'); history_pg_stat_activity_query = regexp_replace(history_pg_stat_activity_query,'\t+',' ','g'); history_pg_stat_activity_query = regexp_replace(history_pg_stat_activity_query,' +',' ','g'); history_pg_stat_activity_query = regexp_replace(history_pg_stat_activity_query,';','','g'); query_text = trim(trailing ' ' from history_pg_stat_activity_query); FOR pg_stat_history_rec IN SELECT queryid , query FROM --pg_stat_history pg_stat_db_queries WHERE queryid is not null GROUP BY queryid , query LOOP pg_stat_query = pg_stat_history_rec.query ; pg_stat_query=regexp_replace(pg_stat_query,'\n+',' ','g'); pg_stat_query=regexp_replace(pg_stat_query,'\t+',' ','g'); pg_stat_query=regexp_replace(pg_stat_query,' +',' ','g'); pg_stat_query=regexp_replace(pg_stat_query,'\$.','%','g'); pg_stat_query_text = pg_stat_query; IF (query_text LIKE pg_stat_query_text) THEN found_flag = TRUE ; ELSE found_flag = FALSE ; END IF; IF found_flag THEN UPDATE activity_hist.history_pg_stat_activity SET queryid = pg_stat_history_rec.queryid WHERE regexp_replace(regexp_replace(regexp_replace(regexp_replace(query,'\n+',' ','g'),'\t+',' ','g'),' +',' ','g'),';','','g') LIKE query_text||'%' ; activity_string = 'history_pg_stat_activity has updated by queryid = '||pg_stat_history_rec.queryid; RAISE NOTICE '%',activity_string; PERFORM pg_log( 999 , 'update_history_pg_stat_activity_by_queryid' , activity_string); EXIT ; END IF ; END LOOP ; IF NOT found_flag THEN activity_string = 'WARNING : Not FOUND queryid for the query : '||query_text ; RAISE NOTICE '%',activity_string; PERFORM pg_log( 999 , 'update_history_pg_stat_activity_by_queryid' , activity_string); END IF ; RAISE NOTICE 'UPDATE log_query if query has not logged in log-file'; END LOOP; RETURN result ; END $$ LANGUAGE plpgsql;

Par conséquent, la table contient la valeur queryid correspondant à la valeur queryid de la requête.

Résumé

En liant pg_stat_activity, pg_stat_statements, log_query, vous pouvez obtenir de nombreuses informations utiles sur la demande, en particulier:

Historique des plans de mise en œuvre.
Historique de la demande de temps CPU.
Demander l'historique des attentes.

Les données et de nombreux rapports supplémentaires seront décrits dans le prochain article.

Développement

En liant les informations disponibles à l'historique de la vue pg_locks, vous pouvez obtenir des informations sur les verrous spécifiques que la demande attendait et, plus important encore, sur le processus (demande) qui détenait ce verrou.

La solution à ce problème sera décrite dans le prochain article. Des tests et des améliorations sont en cours.

pg_stat_statements + pg_stat_activity + loq_query = pg_ash?