diff options
| author | Tom Lane | 2025-07-15 20:35:42 +0000 |
|---|---|---|
| committer | Tom Lane | 2025-07-15 20:35:42 +0000 |
| commit | 8ffd9ac3b206c0a93f9a16e0341c9f7850d26483 (patch) | |
| tree | b8d2bbbcae46ed89eddecc827db000e2f5f5aa5e /doc/src | |
| parent | ff0bcb248e6ef337902cb26266606c1ab4ea4048 (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
Diffstat (limited to 'doc/src')
| -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 6b327d4fd81..f5a0e0954a1 100644 --- a/doc/src/sgml/func.sgml +++ b/doc/src/sgml/func.sgml @@ -11247,10 +11247,10 @@ 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 4cfd9767f7c..1b38e5d725a 100644 --- a/doc/src/sgml/protocol.sgml +++ b/doc/src/sgml/protocol.sgml @@ -886,6 +886,16 @@ 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> |