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Replace XLOG_INCLUDE_XID flag with a more localized flag.

Browse Source 
Commit 0bead9af48 introduced XLOG_INCLUDE_XID flag to indicate that the
WAL record contains subXID-to-topXID association. It uses that flag later
to mark in CurrentTransactionState that top-xid is logged so that we
should not try to log it again with the next WAL record in the current
subtransaction. However, we can use a localized variable to pass that
information.

In passing, change the related function and variable names to make them
consistent with what the code is actually doing.

Author: Dilip Kumar
Reviewed-by: Alvaro Herrera, Amit Kapila
Discussion: https://postgr.es/m/E1mSoYz-0007Fh-D9@gemulon.postgresql.org
This commit is contained in:
Amit Kapila
2021-11-02 08:35:29 +05:30
parent 43a134f28b
commit 71db6459e6
5 changed files with 82 additions and 68 deletions
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103
src/backend/access/transam/xact.c
View File

@@ -205,7 +205,7 @@ typedef struct TransactionStateData
bool didLogXid; /* has xid been included in WAL record? */
int parallelModeLevel; /* Enter/ExitParallelMode counter */
bool chain; /* start a new block after this one */
bool assigned; /* assigned to top-level XID */
bool topXidLogged; /* for a subxact: is top-level XID logged? */
struct TransactionStateData *parent; /* back link to parent */
} TransactionStateData;
@@ -238,7 +238,7 @@ typedef struct SerializedTransactionState
static TransactionStateData TopTransactionStateData = {
.state = TRANS_DEFAULT,
.blockState = TBLOCK_DEFAULT,
.assigned = false,
.topXidLogged = false,
};
/*
@@ -529,6 +529,56 @@ MarkCurrentTransactionIdLoggedIfAny(void)
CurrentTransactionState->didLogXid = true;
}
/*
* IsSubxactTopXidLogPending
*
* This is used to decide whether we need to WAL log the top-level XID for
* operation in a subtransaction. We require that for logical decoding, see
* LogicalDecodingProcessRecord.
*
* This returns true if wal_level >= logical and we are inside a valid
* subtransaction, for which the assignment was not yet written to any WAL
* record.
*/
bool
IsSubxactTopXidLogPending(void)
{
/* check whether it is already logged */
if (CurrentTransactionState->topXidLogged)
return false;
/* wal_level has to be logical */
if (!XLogLogicalInfoActive())
return false;
/* we need to be in a transaction state */
if (!IsTransactionState())
return false;
/* it has to be a subtransaction */
if (!IsSubTransaction())
return false;
/* the subtransaction has to have a XID assigned */
if (!TransactionIdIsValid(GetCurrentTransactionIdIfAny()))
return false;
return true;
}
/*
* MarkSubxactTopXidLogged
*
* Remember that the top transaction id for the current subtransaction is WAL
* logged now.
*/
void
MarkSubxactTopXidLogged(void)
{
Assert(IsSubxactTopXidLogPending());
CurrentTransactionState->topXidLogged = true;
}
/*
* GetStableLatestTransactionId
@@ -5174,7 +5224,7 @@ PushTransaction(void)
GetUserIdAndSecContext(&s->prevUser, &s->prevSecContext);
s->prevXactReadOnly = XactReadOnly;
s->parallelModeLevel = 0;
s->assigned = false;
s->topXidLogged = false;
CurrentTransactionState = s;
@@ -6106,50 +6156,3 @@ xact_redo(XLogReaderState *record)
else
elog(PANIC, "xact_redo: unknown op code %u", info);
}
/*
* IsSubTransactionAssignmentPending
*
* This is used to decide whether we need to WAL log the top-level XID for
* operation in a subtransaction. We require that for logical decoding, see
* LogicalDecodingProcessRecord.
*
* This returns true if wal_level >= logical and we are inside a valid
* subtransaction, for which the assignment was not yet written to any WAL
* record.
*/
bool
IsSubTransactionAssignmentPending(void)
{
/* wal_level has to be logical */
if (!XLogLogicalInfoActive())
return false;
/* we need to be in a transaction state */
if (!IsTransactionState())
return false;
/* it has to be a subtransaction */
if (!IsSubTransaction())
return false;
/* the subtransaction has to have a XID assigned */
if (!TransactionIdIsValid(GetCurrentTransactionIdIfAny()))
return false;
/* and it should not be already 'assigned' */
return !CurrentTransactionState->assigned;
}
/*
* MarkSubTransactionAssigned
*
* Mark the subtransaction assignment as completed.
*/
void
MarkSubTransactionAssigned(void)
{
Assert(IsSubTransactionAssignmentPending());
CurrentTransactionState->assigned = true;
}