Oracle Database

Oracle Database, the related services (cloud) and various options in the database.

Approximate Query Processing in 12c Release 2

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Approximate Query Processing appears to be a major feature of Oracle Database 12c Release 2 SQL. In 12cR1 patchset 2 (12.1.0.2), we saw one approximate query function appear – APPROX_COUNT_DISTINCT to use instead of COUNT(DISTINCT). In 12.2 there are several APPROX functions introduced:   APPROX_COUNT_DISTINCT_DETAIL APPROX_COUNT_DISTINCT_AGG TO_APPROX_COUNT_DISTINCT APPROX_MEDIAN APPROX_PERCENTILE APPROX_PERCENTILE_DETAIL APPROX_PERCENTILE_AGG TO_APPROX_PERCENTILE According to Oracle … Read more

V$BACKUP_NONLOGGED and V$CON_SYSSTAT in 12c

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V$BACKUP_NONLOGGED is new view in 12c, displays information about nonlogged block ranges in data file backups recorded in the control file. A related view is V$NONLOGGED_BLOCK. It displays ranges of nonlogged datafile blocks recorded in the control file. In version 12c and forward RMAN validate no longer populates view V$DATABASE_BLOCK_CORRUPTION, instead V$NONLOGGED_BLOCK is updated. V$COPY_NONLOGGED … Read more