diff options
| author | Tom Lane | 2022-07-23 23:00:29 +0000 |
|---|---|---|
| committer | Tom Lane | 2022-07-23 23:00:33 +0000 |
| commit | 6955bba0ede45e9379d04d7faaa889448919aa07 (patch) | |
| tree | a29d22acc65431de0d98d7b2cc5e70dd1a0672ff | |
| parent | e757cdd6ad1bc757df7a73616bde8d7e1cb2828a (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.sgml | 3 | ||||
| -rw-r--r-- | 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 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> |