Question about savepoint level?
Hi, hackers
The TransactionStateData has savepointLevel field, however, I do not understand
what is savepoint level, it seems all savepoints have the same savepointLevel,
I want to know how the savepoint level changes.
--
Regrads,
Japin Li.
ChengDu WenWu Information Technology Co.,Ltd.
On Mon, 24 Oct 2022 at 12:19, Japin Li <japinli@hotmail.com> wrote:
Hi, hackers
The TransactionStateData has savepointLevel field, however, I do not understand
what is savepoint level, it seems all savepoints have the same savepointLevel,
I want to know how the savepoint level changes.
I try to remove the savepointLevel, and it seems harmless. Any thoughts?
--
Regrads,
Japin Li.
ChengDu WenWu Information Technology Co.,Ltd.
Attachments:
v1-0001-Remove-useless-savepoint-level.patchtext/x-patchDownload
From 1e5c015efc44bcf2bc93365e99740deb618eebfe Mon Sep 17 00:00:00 2001
From: Japin Li <japinli@hotmail.com>
Date: Mon, 24 Oct 2022 14:54:03 +0800
Subject: [PATCH v1] Remove useless savepoint level
---
src/backend/access/transam/xact.c | 18 ------------------
1 file changed, 18 deletions(-)
diff --git a/src/backend/access/transam/xact.c b/src/backend/access/transam/xact.c
index fd5103a78e..e8a90a3a30 100644
--- a/src/backend/access/transam/xact.c
+++ b/src/backend/access/transam/xact.c
@@ -190,7 +190,6 @@ typedef struct TransactionStateData
FullTransactionId fullTransactionId; /* my FullTransactionId */
SubTransactionId subTransactionId; /* my subxact ID */
char *name; /* savepoint name, if any */
- int savepointLevel; /* savepoint level */
TransState state; /* low-level state */
TBlockState blockState; /* high-level state */
int nestingLevel; /* transaction nesting depth */
@@ -3234,12 +3233,10 @@ CommitTransactionCommand(void)
case TBLOCK_SUBRESTART:
{
char *name;
- int savepointLevel;
/* save name and keep Cleanup from freeing it */
name = s->name;
s->name = NULL;
- savepointLevel = s->savepointLevel;
AbortSubTransaction();
CleanupSubTransaction();
@@ -3247,7 +3244,6 @@ CommitTransactionCommand(void)
DefineSavepoint(NULL);
s = CurrentTransactionState; /* changed by push */
s->name = name;
- s->savepointLevel = savepointLevel;
/* This is the same as TBLOCK_SUBBEGIN case */
AssertState(s->blockState == TBLOCK_SUBBEGIN);
@@ -3263,19 +3259,16 @@ CommitTransactionCommand(void)
case TBLOCK_SUBABORT_RESTART:
{
char *name;
- int savepointLevel;
/* save name and keep Cleanup from freeing it */
name = s->name;
s->name = NULL;
- savepointLevel = s->savepointLevel;
CleanupSubTransaction();
DefineSavepoint(NULL);
s = CurrentTransactionState; /* changed by push */
s->name = name;
- s->savepointLevel = savepointLevel;
/* This is the same as TBLOCK_SUBBEGIN case */
AssertState(s->blockState == TBLOCK_SUBBEGIN);
@@ -4352,11 +4345,6 @@ ReleaseSavepoint(const char *name)
(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
errmsg("savepoint \"%s\" does not exist", name)));
- /* disallow crossing savepoint level boundaries */
- if (target->savepointLevel != s->savepointLevel)
- ereport(ERROR,
- (errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
- errmsg("savepoint \"%s\" does not exist within current savepoint level", name)));
/*
* Mark "commit pending" all subtransactions up to the target
@@ -4461,11 +4449,6 @@ RollbackToSavepoint(const char *name)
(errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
errmsg("savepoint \"%s\" does not exist", name)));
- /* disallow crossing savepoint level boundaries */
- if (target->savepointLevel != s->savepointLevel)
- ereport(ERROR,
- (errcode(ERRCODE_S_E_INVALID_SPECIFICATION),
- errmsg("savepoint \"%s\" does not exist within current savepoint level", name)));
/*
* Mark "abort pending" all subtransactions up to the target
@@ -5253,7 +5236,6 @@ PushTransaction(void)
s->parent = p;
s->nestingLevel = p->nestingLevel + 1;
s->gucNestLevel = NewGUCNestLevel();
- s->savepointLevel = p->savepointLevel;
s->state = TRANS_DEFAULT;
s->blockState = TBLOCK_SUBBEGIN;
GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
--
2.25.1
On Mon, Oct 24, 2022 at 3:00 PM Japin Li <japinli@hotmail.com> wrote:
On Mon, 24 Oct 2022 at 12:19, Japin Li <japinli@hotmail.com> wrote:
The TransactionStateData has savepointLevel field, however, I do not
understand
what is savepoint level, it seems all savepoints have the same
savepointLevel,
I want to know how the savepoint level changes.
I try to remove the savepointLevel, and it seems harmless. Any thoughts?
ISTM the savepointLevel always remains the same as what is in
TopTransactionStateData after looking at the codes. Now I also get
confused. Maybe what we want is nestingLevel?
Thanks
Richard
On 2022-Oct-24, Richard Guo wrote:
On Mon, Oct 24, 2022 at 3:00 PM Japin Li <japinli@hotmail.com> wrote:
I try to remove the savepointLevel, and it seems harmless. Any thoughts?
ISTM the savepointLevel always remains the same as what is in
TopTransactionStateData after looking at the codes. Now I also get
confused. Maybe what we want is nestingLevel?
This has already been discussed:
/messages/by-id/1317297307-sup-7945@alvh.no-ip.org
Now that we have transaction-controlling procedures, I think the next
step is to add the SQL-standard feature that allows savepoint level
control for them, which would make the savepointLevel no longer dead
code.
--
Álvaro Herrera 48°01'N 7°57'E — https://www.EnterpriseDB.com/
"You're _really_ hosed if the person doing the hiring doesn't understand
relational systems: you end up with a whole raft of programmers, none of
whom has had a Date with the clue stick." (Andrew Sullivan)
On Mon, 24 Oct 2022 at 17:56, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
This has already been discussed:
/messages/by-id/1317297307-sup-7945@alvh.no-ip.org
Sorry for my lazy search.
Now that we have transaction-controlling procedures, I think the next
step is to add the SQL-standard feature that allows savepoint level
control for them, which would make the savepointLevel no longer dead
code.
So the savepoint level is used for CREATE PROCEDURE ... OLD/NEW SAVEPOINT LEVEL
syntax [1]https://www.ibm.com/docs/en/db2/10.1.0?topic=statements-create-procedure-sql, right?
[1]: https://www.ibm.com/docs/en/db2/10.1.0?topic=statements-create-procedure-sql
--
Regrads,
Japin Li.
ChengDu WenWu Information Technology Co.,Ltd.
On 2022-Oct-24, Japin Li wrote:
On Mon, 24 Oct 2022 at 17:56, Alvaro Herrera <alvherre@alvh.no-ip.org> wrote:
Now that we have transaction-controlling procedures, I think the next
step is to add the SQL-standard feature that allows savepoint level
control for them, which would make the savepointLevel no longer dead
code.So the savepoint level is used for CREATE PROCEDURE ... OLD/NEW SAVEPOINT LEVEL
syntax [1], right?[1] https://www.ibm.com/docs/en/db2/10.1.0?topic=statements-create-procedure-sql
Yeah, that's what I understand. The default behavior is the current
behavior (OLD SAVEPOINT LEVEL). In a procedure that specifies NEW
SAVEPOINT LEVEL trying to rollback a savepoint that was defined before
the procedure was called is an error, which sounds a useful protection.
--
Álvaro Herrera Breisgau, Deutschland — https://www.EnterpriseDB.com/
"El sentido de las cosas no viene de las cosas, sino de
las inteligencias que las aplican a sus problemas diarios
en busca del progreso." (Ernesto Hernández-Novich)
On Mon, Oct 24, 2022 at 6:01 PM Alvaro Herrera <alvherre@alvh.no-ip.org>
wrote:
On 2022-Oct-24, Richard Guo wrote:
ISTM the savepointLevel always remains the same as what is in
TopTransactionStateData after looking at the codes. Now I also get
confused. Maybe what we want is nestingLevel?This has already been discussed:
/messages/by-id/1317297307-sup-7945@alvh.no-ip.org
Now that we have transaction-controlling procedures, I think the next
step is to add the SQL-standard feature that allows savepoint level
control for them, which would make the savepointLevel no longer dead
code.
Now I see the context. Thanks for pointing that out.
Thanks
Richard