Thread: BUG #17824: PQTRANS_ACTIVE misleading
The following bug has been logged on the website: Bug reference: 17824 Logged by: Andy Schoenberger Email address: akschoenberger@gmail.com PostgreSQL version: 15.2 Operating system: All Description: The documentation for PQTRANS_ACTIVE [1] does not make explicitly clear that it is returned in *all* cases where there is a command in progress on an okay connection, and not just in the case that there is a command in progress inside of a transaction [2]. With a name like PQTRANS_ACTIVE, I believe it is worth making clear that it can happen when a transaction is not active. I believe this has led to multiple bugs in other programs that attempt to display the current status of a transaction, including a possible one in psql [3]. Assuming I am understanding everything correctly, I think the documentation should probably be updated to make clear that PQTRANS_ACTIVE does not mean that a transaction is active. Best, Andy [1] From: https://www.postgresql.org/docs/15/libpq-status.html#LIBPQ-PQTRANSACTIONSTATUS > Returns the current in-transaction status of the server. > The status can be PQTRANS_IDLE (currently idle), PQTRANS_ACTIVE (a command is in progress), PQTRANS_INTRANS (idle, in a valid transaction block), or PQTRANS_INERROR (idle, in a failed transaction block). PQTRANS_UNKNOWN is reported if the connection is bad. PQTRANS_ACTIVE is reported only when a query has been sent to the server and not yet completed. [2] https://github.com/postgres/postgres/blob/d69cd3a2e29c68a3fdfd4e97167f9a7c6ad29e80/src/interfaces/libpq/fe-connect.c#L6729 [3] The psql documentation below shows that a `*` character is present when a transaction is active: From: https://www.postgresql.org/docs/current/app-psql.html#APP-PSQL-PROMPTING > Transaction status: an empty string when not in a transaction block, or * when in a transaction block, or ! when in a failed transaction block, or ? when the transaction state is indeterminate (for example, because there is no connection). …but a `*` character is also technically used if the transaction status is PQTRANS_ACTIVE, which does not necessarily happen during a transaction. https://github.com/postgres/postgres/blob/46d490ac19a7ca93a5c0f47e5a0e759b5385a8ae/src/bin/psql/prompt.c#L236 I’m not sure if this is actually considered a bug or not since I don’t think psql displays a new prompt until after the command completes, but the logic in the code being misleading does not help.
On Wed, Mar 8, 2023 at 8:28 AM PG Bug reporting form <noreply@postgresql.org> wrote:
The following bug has been logged on the website:
Bug reference: 17824
Logged by: Andy Schoenberger
Email address: akschoenberger@gmail.com
PostgreSQL version: 15.2
Operating system: All
Description:
The documentation for PQTRANS_ACTIVE [1] does not make explicitly clear that
it is returned in *all* cases where there is a command in progress on an
okay connection, and not just in the case that there is a command in
progress inside of a transaction [2]. With a name like PQTRANS_ACTIVE, I
believe it is worth making clear that it can happen when a transaction is
not active.
It is not possible for the server to execute a command without there being an active transaction in progress.
…but a `*` character is also technically used if the transaction status is
PQTRANS_ACTIVE, which does not necessarily happen during a transaction.
https://github.com/postgres/postgres/blob/46d490ac19a7ca93a5c0f47e5a0e759b5385a8ae/src/bin/psql/prompt.c#L236
I’m not sure if this is actually considered a bug or not since I don’t think
psql displays a new prompt until after the command completes, but the logic
in the code being misleading does not help.
Right, it is difficult to report on/see the implicit transaction that occurs if you send a command to the server without constructing an explicit transaction block, since it goes away as the command execution ends.
David J.
PG Bug reporting form <noreply@postgresql.org> writes: > The documentation for PQTRANS_ACTIVE [1] does not make explicitly clear that > it is returned in *all* cases where there is a command in progress on an > okay connection, and not just in the case that there is a command in > progress inside of a transaction [2]. With a name like PQTRANS_ACTIVE, I > believe it is worth making clear that it can happen when a transaction is > not active. The existing documentation defines it as "a command is in progress", which seems perfectly clear to me --- adding more words would just muddy the waters. Also, if a command is running then the server *does* have a transaction open -- it might be an auto-started, auto-committed one, but there's always a transaction. You seem to be using that word in a way that does not correspond with common Postgres usage. (Note that the definitions for PQTRANS_INTRANS and PQTRANS_INERROR say "transaction block" not "transaction", to comport with our usual terminology.) regards, tom lane