FPSBASE.ADM_LOG_SWITCHES

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> FPSBASE.WIP_WAFER_HIST_LOOP

View FPSADMIN.ADM_LOG_SWITCHES

The number of redo log switches per day and hour, including the total size in GB for the entire redo log of each day. Once a redo log is completely filled, Oracle switches to the next and starts over again. Log switches can also be triggered by a fixed time interval or manually. The redo log is necessary to recover data, and it contains all changes made to the data, i.e. both committed and uncommitted. Each transaction is synchronously written to the redo log buffer, after which the log writer process (LGWR) writes the entries into the online redo log file, of which only one is active at any time. See the Oracle Concepts Manual for more details. It includes an ORDER BY clause, so that additional ordering by the user is not necessary. Note that the ORDER BY clause causes any further ordering to be done again. The following query can be used as an alternative. It allows for more easy querying. SELECT hist.log_day ,hist.log_hour ,hist.num_switches ,round(hist.num_switches * avg_bytes/1024/1024) AS size_mb FROM ( SELECT TO_CHAR(first_time, 'YYYY-MM-DD') AS log_day, TO_CHAR(first_time, 'HH24') AS log_hour, COUNT(1) AS num_switches FROM v$log_history GROUP BY ROLLUP(TO_CHAR(first_time, 'YYYY-MM-DD'), TO_CHAR(first_time, 'HH24'))) hist ,(SELECT AVG(bytes) avg_bytes FROM v$log) lg ORDER BY hist.log_day DESC, hist.log_hour;