From 24da0e761837fc0c0ef5733519595c848e5fe280 Mon Sep 17 00:00:00 2001
From: Michael Paquier <michael@paquier.xyz>
Date: Thu, 28 Nov 2024 09:43:28 +0900
Subject: [PATCH] Revert "Handle better implicit transaction state of pipeline
mode"
This reverts commit d77f91214fb7 on all stable branches, due to concerns
regarding the compatility side effects this could create in a minor
release. The change still exists on HEAD.
Discussion: https://postgr.es/m/CA+TgmoZqRgeFTg4+Yf_CMRRXiHuNz1u6ZC4FvVk+rxw0RmOPnw@mail.gmail.com
Backpatch-through: 13
---
doc/src/sgml/protocol.sgml | 21 ++++++++++-----------
src/backend/access/transam/xact.c | 13 +++++++++++++
src/backend/tcop/postgres.c | 18 ------------------
3 files changed, 23 insertions(+), 29 deletions(-)
diff --git a/doc/src/sgml/protocol.sgml b/doc/src/sgml/protocol.sgml
index 9a5b7eeb4a8..812c07e500f 100644
--- a/doc/src/sgml/protocol.sgml
+++ b/doc/src/sgml/protocol.sgml
@@ -1088,17 +1088,16 @@ SELCT 1/0;<!-- this typo is intentional -->
<para>
If the client has not issued an explicit <command>BEGIN</command>,
- then an implicit transaction block is started and each Sync ordinarily
- causes an implicit <command>COMMIT</command> if the preceding step(s)
- succeeded, or an implicit <command>ROLLBACK</command> if they failed.
- This implicit transaction block will only be detected by the server
- when the first command ends without a sync. There are a few DDL
- commands (such as <command>CREATE DATABASE</command>) that cannot be
- executed inside a transaction block. If one of these is executed in a
- pipeline, it will fail unless it is the first command after a Sync.
- Furthermore, upon success it will force an immediate commit to preserve
- database consistency. Thus a Sync immediately following one of these
- commands has no effect except to respond with ReadyForQuery.
+ then each Sync ordinarily causes an implicit <command>COMMIT</command>
+ if the preceding step(s) succeeded, or an
+ implicit <command>ROLLBACK</command> if they failed. However, there
+ are a few DDL commands (such as <command>CREATE DATABASE</command>)
+ that cannot be executed inside a transaction block. If one of
+ these is executed in a pipeline, it will fail unless it is the first
+ command in the pipeline. Furthermore, upon success it will force an
+ immediate commit to preserve database consistency. Thus a Sync
+ immediately following one of these commands has no effect except to
+ respond with ReadyForQuery.
</para>
<para>
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index 423545e6038..ffe26e26f66 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -3405,6 +3405,16 @@ PreventInTransactionBlock(bool isTopLevel, const char *stmtType)
errmsg("%s cannot run inside a subtransaction",
stmtType)));
+ /*
+ * inside a pipeline that has started an implicit transaction?
+ */
+ if (MyXactFlags & XACT_FLAGS_PIPELINING)
+ ereport(ERROR,
+ (errcode(ERRCODE_ACTIVE_SQL_TRANSACTION),
+ /* translator: %s represents an SQL statement name */
+ errmsg("%s cannot be executed within a pipeline",
+ stmtType)));
+
/*
* inside a function call?
*/
@@ -3516,6 +3526,9 @@ IsInTransactionBlock(bool isTopLevel)
if (IsSubTransaction())
return true;
+ if (MyXactFlags & XACT_FLAGS_PIPELINING)
+ return true;
+
if (!isTopLevel)
return true;
diff --git a/src/backend/tcop/postgres.c b/src/backend/tcop/postgres.c
index d375d845b97..ec630b44916 100644
--- a/src/backend/tcop/postgres.c
+++ b/src/backend/tcop/postgres.c
@@ -2656,17 +2656,6 @@ start_xact_command(void)
xact_started = true;
}
- else if (MyXactFlags & XACT_FLAGS_PIPELINING)
- {
- /*
- * When the first Execute message is completed, following commands
- * will be done in an implicit transaction block created via
- * pipelining. The transaction state needs to be updated to an
- * implicit block if we're not already in a transaction block (like
- * one started by an explicit BEGIN).
- */
- BeginImplicitTransactionBlock();
- }
/*
* Start statement timeout if necessary. Note that this'll intentionally
@@ -4616,13 +4605,6 @@ PostgresMain(int argc, char *argv[],
case 'S': /* sync */
pq_getmsgend(&input_message);
-
- /*
- * If pipelining was used, we may be in an implicit
- * transaction block. Close it before calling
- * finish_xact_command.
- */
- EndImplicitTransactionBlock();
finish_xact_command();
send_ready_for_query = true;
break;
--
2.39.5