Redshift Research Project

System Table Tracker

System view pg_catalog.svv_sem_usage version 1.0.39009 / 2022-06-08

schema name column data type
pg_catalog svv_sem_usage expected_wait_msec numeric(24,3)
pg_catalog svv_sem_usage longest_sec numeric(24,3)
pg_catalog svv_sem_usage miss_ratio float8
pg_catalog svv_sem_usage miss_wait_msec numeric(23,2)
pg_catalog svv_sem_usage name char(25)
pg_catalog svv_sem_usage requests int8
pg_catalog svv_sem_usage waits int8
pg_catalog svv_sem_usage wait_time_sec numeric(24,3)

View Text

       round((CAST(sum(stv_sem_usage.count) AS double precision) / CAST(sum(stv_sem_usage.mutex_requests) AS double precision)) * CAST(100.0 AS double precision),
             CAST(2 AS numeric)) AS miss_ratio,
       sum(stv_sem_usage.count) AS waits,
       sum(stv_sem_usage.mutex_requests) AS requests,
       round(CAST(sum(stv_sem_usage.waiting_time) AS numeric) / 1000000.0,
             3) AS wait_time_sec,
       round(CAST(max(stv_sem_usage.longest) AS numeric) / 1000000.0,
             3) AS longest_sec,
       round((CAST(sum(stv_sem_usage.waiting_time) AS numeric) / 1000.0) / CAST(sum(stv_sem_usage.count) AS numeric),
             2) AS miss_wait_msec,
       round((CAST(sum(stv_sem_usage.waiting_time) AS numeric) / 1000.0) / CAST(sum(stv_sem_usage.mutex_requests) AS numeric),
             3) AS expected_wait_msec
FROM stv_sem_usage
WHERE stv_sem_usage.node < 1000
HAVING sum(stv_sem_usage.count) > 0
   AND sum(stv_sem_usage.mutex_requests) > 0
ORDER BY round(CAST(sum(stv_sem_usage.waiting_time) AS numeric) / 1000000.0,
               3) DESC

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