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

pg_stat_statements + pg_stat_activity + loq_query = pg_ash?

Kot drži kratek dodatek k članku Poskus ustvarjanja analoga ASH za PostgreSQL.

Naloga

Potrebno je povezati zgodovino prikazov pg_stat_statements, pg_stat_activity. Posledično lahko s pomočjo zgodovine izvedbenih načrtov iz servisne tabele log_query pridobimo veliko koristnih informacij za reševanje težav z zmogljivostjo in optimizacijo poizvedb.

Opozorilo.

Ker se testiranje in razvoj nadaljujeta, članek ne more posegati po opisu končne industrijske rešitve.

Kritike in pripombe glede izvedbe so dobrodošle in pričakovane.

Vhodni podatki

Tabela 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
);

Tabela pg_stat_db_queries

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

Materializiran pogled 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;

Tabela 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 
);

Skupni algoritem

Posodobiti tabelo pg_stat_db_queries

Posodobiti materializiran pogled 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;

Napolniti tabelo pg_stat_db_queries

USTVARITE ALI ZAMENITE FUNKCIJO refresh_pg_stat_db_queries( ) VRNE BOOLEAN AS $$
DECLARE
 rezultat BOOLEAN ;
 zapis_baze record ;  
 pg_stat_rec record ;
BEGIN 
  TRUNCATE pg_stat_db_queries;
  
  
  ZA zapis_baze IN
  IZ baze d 
  LOOP
  
    ČE NE zapis_baze.is_need_monitoring POTEM RAISE NOTICE 'NI POTREBA POZORNOSTI ZA database_id=%',zapis_baze.id; NASTAVI ; KONEC ČE ;
   
    PERFORM refresh_pg_stat_queries_list( zapis_baze.id ) ; 
	
	ZA pg_stat_rec IN
	IZ mvw_pg_stat_queries 
	LOOP
	  VSTAVI V pg_stat_db_queries
	  ( database_id , queryid , query , max_time )
	  VREDNOSTI
	  ( zapis_baze.id , pg_stat_rec.queryid , pg_stat_rec.query , pg_stat_rec.max_time);
	KONEC LOOP;     
  KONEC LOOP; 

  VRNI TRUE;
KONEC
$$ JEZIK plpgsql;

Rezultatna tabela vsebuje normalizirane besedilne poizvedbe, queryid, največji čas izvajanja poizvedbe v trenutnem trenutku (uporablja se za spremljanje).

Izpolnjevanje log_query in oblikovanje zgodovine načrtov izvajanja.

Aktualno besedilo poizvedbe se vzame iz log-datoteke. Log-datoteka z ciljnega gostitelja se na gostitelj spremljanja prenaša po delih, s pomočjo bash skripta, preko crona. Zaradi varčevanja s prostorom in zaradi trivialnosti naloge kopiranja dela besedilne datoteke z gostitelja na gostitelja skripta ni priložena.

Parsiraje log-datoteke in izločitev besedila poizvedbe.

#!/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

Izpolnjevanje tabele log_query

--log_query.sql
--vstavi novu upit u tablicu log_query
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 );
  
  --Objašnjenje izvršnog plana--
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 = 	'Nova upit je zabilježen '||
						' 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 = 	'IZUZETAK *** upit je već zabilježen '||
							' 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 = 	' ažuriran queryid = '||pg_stat_history_rec.queryid||
		                    ' za log_query s id = '||log_query_rec.id;					
		EXIT ;
	  END IF ;	  
	END LOOP ;	
  RETURN result ;
END
$$ LANGUAGE plpgsql;

Zato tabela vsebuje aktualno besedilo poizvedbe, načrte izvajanja, hash vrednost načrta izvajanja in hash vrednost besedila poizvedbe.

Napolnite vrednost queryid v tabeli history_pg_stat_activity

update_history_pg_stat_activity_by_queryid.sql

--update_history_pg_stat_activity_by_queryid.sql
USTVARI ALI ZAMENJAJ FUNKCIJO update_history_pg_stat_activity_by_queryid() VRAČA boolean AS $$
DECLARE
  rezultat 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';
  
  rezultat = 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 = 'OPOZORILO : Ni najden queryid za poizvedbo : '||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 če poizvedba ni bila zabeležena v datoteki dnevnika';
		
  END LOOP;
  
  RETURN rezultat ;
END
$$ JEzik plpgsql;

Zato tabela vsebuje vrednost queryid, ki ustreza vrednosti queryid poizvedbe.

Zaključek

S povezovanjem pg_stat_activity, pg_stat_statements in log_query lahko dobimo veliko koristnih informacij o poizvedbi, zlasti:

  • Zgodovina načrtov izvajanja.
  • Zgodovina CPU-čas poizvedbe.
  • Zgodovina čakanja poizvedbe.

Podatki in številni dodatni poročili bodo obravnavani v naslednjem članku.

Razvoj

Povezivanjem dostupnih informacija s poviješću prikaza pg_locks može se dobiti informacija o tome koju je konkretno blokadu čekao zahtjev i, što je najvažnije, koji je proces (zahtjev) zadržavao tu blokadu.

Rješenje ovog problema bit će opisano u sljedećem članku. Trenutno se provodi testiranje i dorada.

Izvor: habr.com

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