postgres.git / summary / log / commit / refs

commit    31d5354cb148c6aa90014f62d3a4752adeebd51a
Author:   Tom Lane <tgl@sss.pgh.pa.us>
Date:     Sat Jul 23 23:00:30 2022 +0000
First released in: 16.0, 12.12, 13.8, 14.5, 15.0

    Doc: improve documentation about random().
    
    We didn't explicitly say that random() uses a randomly-chosen seed
    if you haven't called setseed().  Do so.
    
    Also, remove ref/set.sgml's no-longer-accurate (and never very
    relevant) statement that the seed value is multiplied by 2^31-1.
    
    Back-patch to v12 where set.sgml's claim stopped being true.
    The claim that we use a source of random bits as seed was debatable
    before 4203842a1, too, so v12 seems like a good place to stop.
    
    Per question from Carl Sopchak.
    
    Discussion: https://postgr.es/m/f37bb937-9d99-08f0-4de7-80c91a3cfc2e@sopchak.me


 doc/src/sgml/func.sgml    | 3 +++
 doc/src/sgml/ref/set.sgml | 3 +--
 2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 6ce54c1ee1f..ac8b7e519a0 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1840,6 +1840,9 @@ repeat('Pg', 4) <returnvalue>PgPgPgPg</returnvalue>
    subsequent <function>random()</function> calls in the current session
    can be repeated by re-issuing <function>setseed()</function> with the same
    argument.
+   Without any prior <function>setseed()</function> call in the same
+   session, the first <function>random()</function> call obtains a seed
+   from a platform-dependent source of random bits.
   </para>
 
   <para>
diff --git a/doc/src/sgml/ref/set.sgml b/doc/src/sgml/ref/set.sgml
index 339ee9eec94..c4aab56a2d3 100644
--- a/doc/src/sgml/ref/set.sgml
+++ b/doc/src/sgml/ref/set.sgml
@@ -175,8 +175,7 @@ SET [ SESSION | LOCAL ] TIME ZONE { <replaceable class="parameter">timezone</rep
       <para>
        Sets the internal seed for the random number generator (the
        function <function>random</function>).  Allowed values are
-       floating-point numbers between -1 and 1, which are then
-       multiplied by 2<superscript>31</superscript>-1.
+       floating-point numbers between -1 and 1 inclusive.
       </para>
 
       <para>


[parent: fee0165fc1cf]