SQL Functions and Statements

New Approximate Count Distinct Function

Support for aggregating approximate count distinct data now includes a new function:

APPROXIMATE_COUNT_DISTINCT_SYNOPSIS_MERGE ( synopsis-obj [, error-tolerance] )

This function aggregates multiple synopses in the same format into one new synopsis of that format. It is similar to APPROXIMATE_COUNT_DISTINCT_OF_SYNOPSIS but returns one synopsis instead of the count estimate. The benefit of this new function is to speed up final estimation when calling APPROXIMATE_COUNT_DISTINCT_OF_SYNOPSIS. For example, to regularly estimate the approximate count distinct of users for a long period (say, several years) you can pre-accumulate synopses of days into one synopsis for a year.

Extended COPY Support for EXPLAIN

In previous releases, EXPLAIN COPY returned a query plan only in Graphviz DOT notation. COPY statements now support all EXPLAIN output options, excluding ANNOTATED:

  • LOCAL
  • VERBOSE
  • JSON

Unqualified, EXPLAIN generates a text query plan together with Graphviz DOT notation.

Per-Connection Override of Default TLS Settings

The CONNECT statement has a new, optional parameter, TLSMODE, that you can use to override the global TLS enforcement level set in ImportExportTLSMode. For more information, see Security Parameters.

Altering Spread Options

You can now alter the spread daemon's Timeout Token setting using the SET_SPREAD_OPTION function. You might want to change this option when using Vertica on Azure. See Adjusting Spread Daemon Timeouts For Virtual Environments for more information.

Extended COPY support for EXPLAIN

  • LOCAL
  • VERBOSE
  • JSON

Unqualified, EXPLAIN generates a text query plan together with Graphviz DOT notation.