diff options
| -rw-r--r-- | doc/src/sgml/acronyms.sgml | 20 | ||||
| -rw-r--r-- | doc/src/sgml/planstats.sgml | 2 |
2 files changed, 21 insertions, 1 deletions
diff --git a/doc/src/sgml/acronyms.sgml b/doc/src/sgml/acronyms.sgml index 2df6559accc..a60ff54a6ce 100644 --- a/doc/src/sgml/acronyms.sgml +++ b/doc/src/sgml/acronyms.sgml @@ -409,6 +409,26 @@ </varlistentry> <varlistentry> + <term><acronym>MCF</acronym></term> + <listitem> + <para> + Most Common Frequency, that is the frequency associated with some + Most Common Value + </para> + </listitem> + </varlistentry> + + <varlistentry> + <term><acronym>MCV</acronym></term> + <listitem> + <para> + Most Common Value, one of the values appearing most often within a + particular table column + </para> + </listitem> + </varlistentry> + + <varlistentry> <term><acronym>MITM</acronym></term> <listitem> <para> diff --git a/doc/src/sgml/planstats.sgml b/doc/src/sgml/planstats.sgml index df85ea5eea4..d2b84b301f5 100644 --- a/doc/src/sgml/planstats.sgml +++ b/doc/src/sgml/planstats.sgml @@ -203,7 +203,7 @@ EXPLAIN SELECT * FROM tenk1 WHERE stringu1 = 'xxx'; <acronym>MCV</acronym>s: <programlisting> -selectivity = (1 - sum(mvf))/(num_distinct - num_mcv) +selectivity = (1 - sum(mcv_freqs))/(num_distinct - num_mcv) = (1 - (0.00333333 + 0.003 + 0.003 + 0.003 + 0.003 + 0.003 + 0.003 + 0.003 + 0.003 + 0.003))/(676 - 10) = 0.0014559 |