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 firstcommand of a transaction, but might

differ during subsequentcommands.

return the same value during the firststatement of a transaction, but might

differ during subsequentstatements.

<function>clock_timestamp()</function> returns the actual current time, and

therefore its value changes even within a single SQLcommand.

therefore its value changes even within a single SQLstatement.

<function>timeofday()</function> is a historical

<productname>PostgreSQL</productname> function. Like

<function>clock_timestamp()</function>, it returns the actual current time,

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>