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authorTom Lane2022-07-23 23:00:29 +0000
committerTom Lane2022-07-23 23:00:33 +0000
commit6955bba0ede45e9379d04d7faaa889448919aa07 (patch)
treea29d22acc65431de0d98d7b2cc5e70dd1a0672ff
parente757cdd6ad1bc757df7a73616bde8d7e1cb2828a (diff)
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/[email protected]
-rw-r--r--doc/src/sgml/func.sgml3
-rw-r--r--doc/src/sgml/ref/set.sgml3
2 files changed, 4 insertions, 2 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml
index 36c3e53e42..21f8ab73e2 100644
--- a/doc/src/sgml/func.sgml
+++ b/doc/src/sgml/func.sgml
@@ -1841,6 +1841,9 @@ 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 ae508d026e..5878c61f9b 100644
--- a/doc/src/sgml/ref/set.sgml
+++ b/doc/src/sgml/ref/set.sgml
@@ -177,8 +177,7 @@ 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>