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Det er nødvendigt at knytte historien om pg_stat_statemenets og pg_stat_activity. Som følge heraf kan man ved at bruge historikken for udførelsesplaner fra service-tabellen log_query få meget nyttig information til brug i løsningen af ydeevneproblemer og optimering af forespørgsler.
Advarsel.
På grund af fortsatte tests og udvikling kan artiklen ikke betragtes som en beskrivelse af en færdig industriel løsning.
Kritik og bemærkninger til implementeringen er meget velkomne og forventes.
Inddata
Tabellen 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
);Tabellen pg_stat_db_queries
CREATE TABLE pg_stat_db_queries
(
database_id integer ,
queryid bigint ,
query text ,
max_time double precision
);(Materialiseret visning 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;
Tabellen 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
);Generel algoritme
Opdater tabel pg_stat_db_queries
Opdater den materialiserede visning 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;Udfyld tabel pg_stat_db_queries
OPRET ELLER ERSTAT FUNKTION refresh_pg_stat_db_queries( ) RETURNER BOOLEAN AS $$
ERKLÆR
resultat BOOLEAN ;
database_rec record ;
pg_stat_rec record ;
BEGIN
TRUNCER pg_stat_db_queries;
FOR database_rec IN
SELECT *
FROM database d
LOOP
IF NOT database_rec.is_need_monitoring THEN RAISE NOTICE 'INGEN BEHOV FOR OVERVÅGNING AF database_id=%',database_rec.id; CONTINUER ; END IF ;
PERFORM refresh_pg_stat_queries_list( database_rec.id ) ;
FOR pg_stat_rec IN
SELECT *
FROM mvw_pg_stat_queries
LOOP
INSERT INTO pg_stat_db_queries
( database_id , queryid , query , max_time )
VALUES
( database_rec.id , pg_stat_rec.queryid , pg_stat_rec.query , pg_stat_rec.max_time);
END LOOP;
END LOOP;
RETURNER TRUE;
END
$$ SPROG plpgsql;Som et resultat indeholder tabellen normaliserede tekster af forespørgsler, queryid, den maksimale udførelsestid for forespørgslen på nuværende tidspunkt (anvendes til overvågning).
Udfyldning af log_query og dannelse af historik over udførelsesplaner.
Den aktuelle tekst af forespørgslen tages fra log-filen. Log-filen overføres fra den målhost til overvågningshosten i bidder, med et bash-script, via cron. For at spare plads og på grund af opgavens trivielle karakter vises scriptet til kopiering af stykker af tekstfilen fra host til host ikke.
Parsing af log-filen og udtrækning af forespørgslen tekst
#!/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
doneUdfyldning af tabellen log_query
--log_query.sql
--indsæt ny forespørgsel i log_query-tabellen
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 );
--Forklar udførelsesplan--
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 = 'Ny forespørgsel er logget '||
' 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 = 'UNDTAGELSE *** forespørgsel er allerede logget '||
' 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 = ' opdateret queryid = '||pg_stat_history_rec.queryid||
' for log_query med id = '||log_query_rec.id;
EXIT ;
END IF ;
END LOOP ;
RETURN result ;
END
$$ LANGUAGE plpgsql;Som følger indeholder tabellen den aktuelle forespørgselstekst, udførelsesplaner, hashsum for udførelsesplanen og hashsum for forespørgselsteksten.
Udfyld værdi queryid i tabellen 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;Som følge heraf indeholder tabellen værdien queryid svarende til forespørgselens queryid.
Resultat
Ved at sammenkoble pg_stat_activity, pg_stat_statements, log_query kan man få mange nyttige oplysninger om forespørgslen, herunder:
- Historik over udførelsesplaner.
- Historik over forespørgslens CPU-tid.
- Historik over forespørgslens ventetid.
Data og mange yderligere rapporter vil blive beskrevet i næste artikel.
Udvikling
Ved at knytte de tilgængelige oplysninger med historikken for pg_locks kan man få information om, hvilken specifik lås forespørgslen ventede på, og vigtigst af alt, hvilken proces (forespørgsel) der holdt denne lås.
Løsningen på denne opgave vil blive beskrevet i den næste artikel. For nu er der testning og revidering i gang.
Kilde: habr.com
