diff options
| author | Tom Lane <tgl@sss.pgh.pa.us> | 2025-07-15 16:35:42 -0400 |
|---|---|---|
| committer | Tom Lane <tgl@sss.pgh.pa.us> | 2025-07-15 16:36:04 -0400 |
| commit | bdb052f53b1afc3218f0993cadecdcd4df94f903 (patch) | |
| tree | b3d17c7952249391f8f53dd5616dce34ce6e1166 | |
| parent | 50959f96e7b17c3f225919edbec4072c033aef60 (diff) | |
Doc: clarify description of current-date/time functions.
Minor wordsmithing of the func.sgml paragraph describing
statement_timestamp() and allied functions: don't switch between
"statement" and "command" when those are being used to mean about
the same thing.
Also, add some text to protocol.sgml describing the perhaps-surprising
behavior these functions have in a multi-statement Query message.
Reported-by: P M <petermittere@gmail.com>
Author: Tom Lane <tgl@sss.pgh.pa.us>
Reviewed-by: Laurenz Albe <laurenz.albe@cybertec.at>
Reviewed-by: David G. Johnston <david.g.johnston@gmail.com>
Discussion: https://postgr.es/m/175223006802.3157505.14764328206246105568@wrigleys.postgresql.org
Backpatch-through: 13
| -rw-r--r-- | doc/src/sgml/func.sgml | 6 | ||||
| -rw-r--r-- | doc/src/sgml/protocol.sgml | 10 |
2 files changed, 13 insertions, 3 deletions
diff --git a/doc/src/sgml/func.sgml b/doc/src/sgml/func.sgml index 9db19c5d4ab..fc4b9537871 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -11024,10 +11024,10 @@ now() statement (more specifically, the time of receipt of the latest command message from the client). <function>statement_timestamp()</function> and <function>transaction_timestamp()</function> - return the same value during the first command of a transaction, but might - differ during subsequent commands. + return the same value during the first statement of a transaction, but might + differ during subsequent statements. <function>clock_timestamp()</function> returns the actual current time, and - therefore its value changes even within a single SQL command. + therefore its value changes even within a single SQL statement. <function>timeofday()</function> is a historical <productname>PostgreSQL</productname> function. Like <function>clock_timestamp()</function>, it returns the actual current time, diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml index 1b1894e9751..3a69acfa59c 100644 --- a/doc/src/sgml/protocol.sgml +++ b/doc/src/sgml/protocol.sgml @@ -800,6 +800,16 @@ SELCT 1/0;<!-- this typo is intentional --> Errors detected at semantic analysis or later, such as a misspelled table or column name, do not have this effect. </para> + + <para> + Lastly, note that all the statements within the Query message will + observe the same value of <function>statement_timestamp()</function>, + since that timestamp is updated only upon receipt of the Query + message. This will result in them all observing the same + value of <function>transaction_timestamp()</function> as well, + except in cases where the query string ends a previously-started + transaction and begins a new one. + </para> </sect3> </sect2> |