ProHoster > Blog > Beheer > pg_stat_statements + pg_stat_activity + loq_query = pg_ash?

pg_stat_statements + pg_stat_activity + loq_query = pg_ash?

Als een korte aanvulling op het artikel Poging om een analoog van ASH voor PostgreSQL te creƫren.

Task

Het is noodzakelijk om de geschiedenis van pg_stat_statemenets en pg_stat_activity met elkaar te verbinden. Als gevolg hiervan kan, door de geschiedenis van uitvoeringsplannen uit de servicetabel log_query te gebruiken, veel nuttige informatie worden verkregen voor het oplossen van prestatie-incidenten en het optimaliseren van queries.

Waarschuwing.

In verband met de voortzetting van testen en ontwikkeling kan het artikel niet als een beschrijving van een kant-en-klaar industrieel product worden beschouwd.

Kritiek en opmerkingen over de implementatie worden ten zeerste gewaardeerd en verwacht.

Invoergegevens

Tabel 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
);

Tabel pg_stat_db_queries

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

Gematiseerde weergave 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;

Tabel 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 
);

Algemene algoritme

Tabel pg_stat_db_queries bijwerken

Gematiseerde weergave mvw_pg_stat_queries bijwerken

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;

Tabel pg_stat_db_queries vullen

CREƋER OF VERVANG FUNCTIE refresh_pg_stat_db_queries( ) RETOURNEERT BOOLEAN AS $$
DECLARE
 result BOOLEAN ;
 database_rec record ;  
 pg_stat_rec record ;
BEGIN 
  TRUNCATE pg_stat_db_queries;
  
  
  VOOR database_rec IN
  SELECT *
  FROM database d 
  LOOP
  
    ALS NIET database_rec.is_need_monitoring DAN RAISE NOTICE 'GEEN MONITORING NODIG VOOR database_id=%',database_rec.id; CONTINUE ; EIND ALS ;
   
    PERFORM refresh_pg_stat_queries_list( database_rec.id ) ; 
	
	VOOR pg_stat_rec IN
	SELECT * 
	FROM mvw_pg_stat_queries 
	LOOP
	  INSERT INTO pg_stat_db_queries
	  ( database_id , queryid , query , max_time )
	  WAARDES
	  ( database_rec.id , pg_stat_rec.queryid , pg_stat_rec.query , pg_stat_rec.max_time);
	EIND LOOP;     
  EIND LOOP; 

  RETOURNEER WAAR;
EIND
$$ TAAL plpgsql;

Als gevolg hiervan bevat de tabel genormaliseerde teksten van aanvragen, queryid, de maximale uitvoeringstijd van de aanvraag tot op heden (wordt gebruikt voor monitoring).

Vullen van log_query en het opbouwen van de geschiedenis van uitvoeren plannen.

De actuele tekst van de aanvraag wordt genomen uit het logbestand. Het logbestand van de doelhost naar de monitoringhost wordt in delen, met een bash-script, via cron gekopieerd. Voor ruimtebesparing en vanwege de trivialiteit van de taak om een deel van het tekstbestand van host naar host te kopiƫren, wordt het script niet gegeven.

Parseren van het logbestand en extraheren van de tekst van de aanvraag.

#!/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

Vullen van de tabel log_query.

--log_query.sql
--voeg nieuwe query toe aan log_query tabel
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 = 'lokaal';
	client_port = 'lokaal';
  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 );
  
  --Verklaar uitvoeringsplan--
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 = 	'Nieuwe query is gelogd '||
						' database_id = '|| log_database_id ||
						' query_md5hash='||log_md5hash||
						' , tijdstip = '||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 = 	'UITZONDERING *** query is al gelogd '||
							' database_id = '|| log_database_id ||
							' query_md5hash='||log_md5hash||n							' , tijdstip = '||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 = 	' bijgewerkt queryid = '||pg_stat_history_rec.queryid||
		                    ' voor log_query met id = '||log_query_rec.id;					
		EXIT ;
	  END IF ;	  
	END LOOP ;	
  RETURN result ;
END
$$ LANGUAGE plpgsql;

Als resultaat bevat de tabel de actuele tekst van de query, uitvoeringsplannen, de hash-waarde van het uitvoeringsplan, en de hash-waarde van de querytekst.

Vul de waarde queryid in de tabel 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 is bijgewerkt door 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 = 'WAARSCHUWING : Geen queryid gevonden voor de 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 als de query niet in het logbestand is geregistreerd';
		
  END LOOP;
  
  RETURN result ;
END
$$ LANGUAGE plpgsql;

Als resultaat bevat de tabel de waarde queryid die overeenkomt met de waarde queryid van de query.

Conclusie

Door pg_stat_activity, pg_stat_statements en log_query aan elkaar te koppelen, kan veel nuttige informatie over de query worden verkregen, in het bijzonder:

  • Historie van uitvoeringsplannen.
  • Historie van CPU-tijd van de query.
  • Historie van wachttijden van de query.

Gegevens en een verscheidenheid aan aanvullende rapporten worden in het volgende artikel beschreven.

Ontwikkeling

Door de beschikbare informatie te combineren met de voorgeschiedenis van pg_locks, kan men achterhalen op welke specifieke blokkering de aanvraag wachtte en, het allerbelangrijkste, welk proces (aanvraag) deze blokkering vasthield.

De oplossing voor deze kwestie zal in het volgende artikel worden beschreven. Momenteel wordt het getest en verder ontwikkeld.

Bron: habr.com

Koop betrouwbare webhosting met bescherming tegen DDoS, VPS VDS servers šŸ”„ Koop betrouwbare webhosting met bescherming tegen DDoS, VPS VDS servers | ProHoster