diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2022-07-23 19:00:30 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2022-07-23 19:00:30 -0400 |
| commit | bd6cfbf338e5c3d65b9271f632142716d67d7c34 (patch) | |
| tree | 579c22d54b2955563c0018f7d3dba0b1fc1dd786 | |
| parent | 44d0e41319f2379d610eec059da273ae4e3c4e6f (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/f37bb937-9d99-08f0-4de7-80c91a3cfc2e@sopchak.me
| -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 f62d86048fd..3ff35dfd221 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 ae508d026e2..5878c61f9b7 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> |