The following documentation comment has been logged on the website:
Page: https://www.postgresql.org/docs/15/transaction-iso.html
Description:
https://www.postgresql.org/docs/current/transaction-iso.html#XACT-READ-COMMITTED
Quote:
"<...>When a transaction uses this isolation level, a SELECT query (without
a FOR UPDATE/SHARE clause) sees only data committed before the query began;
it never sees either uncommitted data or changes committed during query
execution by concurrent transactions. <...>"
"... changes committed during ..."
Don't you think this is bad choice of the word, especially while speaking
about "commiting transactions" in very same sentence?
Wouldn't it be better to say something like
<...> it never sees either uncommitted data or changes produced during query
execution by concurrent transactions. <...>
I mean, with read committed isolation level SELECT clearly can see changes
from concurrent transactions, if these transactions COMMITED.
In fact, you can read about that in few lines later:
"<...>Also note that two successive SELECT commands can see different data,
even though they are within a single transaction, if other transactions
commit changes after the first SELECT starts and before the second SELECT
starts. <...>"
The sentences seem to contradict each other because of " it never sees ...
changes committed during ..."