Postgres - непонятные фризы

EXPLAIN (ANALYZE, BUFFERS, WAL, TIMING) SELECT ...

CREATE OR REPLACE FUNCTION core.statistic__get (
  var_sites INTEGER,
  var_day TIMESTAMP,
  var_week TIMESTAMP,
  var_month TIMESTAMP
)
RETURNS TABLE (
  log_day INTEGER,
  reg_day INTEGER,
  reg_week INTEGER,
  reg_month INTEGER
) AS
$body$
DECLARE
    var_users INTEGER;
    /*---*/
    var_log_day INTEGER;
    /*---*/
    var_reg_day INTEGER;
    var_reg_week INTEGER;
    var_reg_month INTEGER;
BEGIN
    CREATE TEMP TABLE IF NOT EXISTS SITE_STATISTIC (
        log_day INTEGER,
        reg_day INTEGER,
        reg_week INTEGER,
        reg_month INTEGER
    ) ON COMMIT DELETE ROWS;
    /****/
    TRUNCATE SITE_STATISTIC;
    /****/
    FOR var_n IN 0..var_sites LOOP
        /***Day***/
        SELECT COALESCE(SUM(login),0)
        INTO var_log_day
        FROM core.statistic_login
        WHERE date>var_day AND site=var_n;
        
        /***Day***/
        SELECT COALESCE(SUM(reg),0)
        INTO var_reg_day
        FROM core.statistic_reg
        WHERE date>var_day AND site=var_n;
        
        /***Week***/
        SELECT COALESCE(SUM(reg),0)
        INTO var_reg_week
        FROM core.statistic_reg
        WHERE date>var_week AND site=var_n;
        
        /***Month***/
        SELECT COALESCE(SUM(reg),0)
        INTO var_reg_month
        FROM core.statistic_reg
        WHERE date>var_month AND site=var_n;
        
        /***Insert***/
        INSERT INTO SITE_STATISTIC (log_day,reg_day,reg_week,reg_month)
        VALUES (var_log_day,var_reg_day,var_reg_week,var_reg_month); 
    END LOOP;
 
    /******Get all users****/
    INSERT INTO SITE_STATISTIC (log_day,reg_day,reg_week,reg_month)
    VALUES ((SELECT COUNT(*) FROM core.user),0,0,0);
    
    /*---*/
    RETURN QUERY SELECT * FROM SITE_STATISTIC;
END
$body$
LANGUAGE 'plpgsql'
VOLATILE
CALLED ON NULL INPUT
SECURITY DEFINER
PARALLEL UNSAFE
COST 100 ROWS 1000;
 
ALTER FUNCTION core.statistic__get (var_sites INTEGER, var_day TIMESTAMP, var_week TIMESTAMP, var_month TIMESTAMP)
  OWNER TO postgres;

CREATE OR REPLACE FUNCTION core.statistic__get (
  var_sites INTEGER,
  var_day TIMESTAMP,
  var_week TIMESTAMP,
  var_month TIMESTAMP
)
RETURNS TABLE (
  log_day INTEGER,
  reg_day INTEGER,
  reg_week INTEGER,
  reg_month INTEGER
) AS
$body$
SELECT *
FROM (
    SELECT  COALESCE(SUM(login),0)
            ,COALESCE(SUM(reg) FILTER(WHERE r.date>var_day),0)
            ,COALESCE(SUM(reg) FILTER(WHERE r.date>var_week),0)
            ,COALESCE(SUM(reg) FILTER(WHERE r.date>var_month),0)
    FROM    generate_series(0,var_sites) var_n
            LEFT JOIN core.statistic_login l ON (l.site = var_n AND l.date > var_day)
            LEFT JOIN core.statistic_reg  r ON (r.site = var_n AND r.date > var_month)
    GROUP   BY var_n
    ORDER   BY var_n
)
UNION   ALL
SELECT  COUNT(*),0,0,0
FROM    core.user;
$body$
LANGUAGE 'sql'
VOLATILE
CALLED ON NULL INPUT
SECURITY DEFINER
PARALLEL UNSAFE
COST 100 ROWS 1000;

LEFT JOIN core.statistic_login l ON (l.site = var_n AND l.date > var_day)
LEFT JOIN core.statistic_reg  r ON (r.site = var_n AND r.date > var_month)

CREATE OR REPLACE FUNCTION core.statistic__get (
  var_sites INTEGER,
  var_day TIMESTAMP,
  var_week TIMESTAMP,
  var_month TIMESTAMP
)
RETURNS TABLE (
  log_day INTEGER,
  reg_day INTEGER,
  reg_week INTEGER,
  reg_month INTEGER
) AS
$body$
BEGIN
    RETURN QUERY SELECT *
    FROM (  
        SELECT 
            (SELECT COALESCE(SUM(login),0)::INTEGER FROM core.statistic_login WHERE site=var_n AND date>var_day),
            (SELECT COALESCE(SUM(reg),0)::INTEGER FROM core.statistic_reg WHERE site=var_n AND date>var_day),
            (SELECT COALESCE(SUM(reg),0)::INTEGER FROM core.statistic_reg WHERE site=var_n AND date>var_week),
            (SELECT COALESCE(SUM(reg),0)::INTEGER FROM core.statistic_reg WHERE site=var_n AND date>var_month)
        FROM generate_series(0,var_sites) var_n
        GROUP BY var_n
        ORDER BY var_n
    ) AS _
    UNION ALL SELECT COUNT(*)::INTEGER,0,0,0 FROM core.user;
END
$body$
LANGUAGE 'plpgsql'
VOLATILE
CALLED ON NULL INPUT
SECURITY DEFINER
PARALLEL UNSAFE
COST 100 ROWS 1000;
 
ALTER FUNCTION core.statistic__get (var_sites INTEGER, var_day TIMESTAMP, var_week TIMESTAMP, var_month TIMESTAMP)
  OWNER TO postgres;