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Report catalog_xmin separately in hot_standby_feedback

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If the upstream walsender is using a physical replication slot, store the
catalog_xmin in the slot's catalog_xmin field. If the upstream doesn't use a
slot and has only a PGPROC entry behaviour doesn't change, as we store the
combined xmin and catalog_xmin in the PGPROC entry.

Author: Craig Ringer
This commit is contained in:
Simon Riggs
2017-03-25 14:07:27 +00:00
parent 4dd3abe99f
commit 5737c12df0
7 changed files with 199 additions and 51 deletions
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43
src/backend/replication/walreceiver.c
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@@ -1175,8 +1175,8 @@ XLogWalRcvSendHSFeedback(bool immed)
{
TimestampTz now;
TransactionId nextXid;
uint32 nextEpoch;
TransactionId xmin;
uint32 xmin_epoch, catalog_xmin_epoch;
TransactionId xmin, catalog_xmin;
static TimestampTz sendTime = 0;
/* initially true so we always send at least one feedback message */
static bool master_has_standby_xmin = true;
@@ -1221,29 +1221,54 @@ XLogWalRcvSendHSFeedback(bool immed)
* everything else has been checked.
*/
if (hot_standby_feedback)
xmin = GetOldestXmin(NULL, PROCARRAY_FLAGS_DEFAULT);
{
TransactionId slot_xmin;
/*
* Usually GetOldestXmin() would include both global replication slot
* xmin and catalog_xmin in its calculations, but we want to derive
* separate values for each of those. So we ask for an xmin that
* excludes the catalog_xmin.
*/
xmin = GetOldestXmin(NULL,
PROCARRAY_FLAGS_DEFAULT|PROCARRAY_SLOTS_XMIN);
ProcArrayGetReplicationSlotXmin(&slot_xmin, &catalog_xmin);
if (TransactionIdIsValid(slot_xmin) &&
TransactionIdPrecedes(slot_xmin, xmin))
xmin = slot_xmin;
}
else
{
xmin = InvalidTransactionId;
catalog_xmin = InvalidTransactionId;
}
/*
* Get epoch and adjust if nextXid and oldestXmin are different sides of
* the epoch boundary.
*/
GetNextXidAndEpoch(&nextXid, &nextEpoch);
GetNextXidAndEpoch(&nextXid, &xmin_epoch);
catalog_xmin_epoch = xmin_epoch;
if (nextXid < xmin)
nextEpoch--;
xmin_epoch --;
if (nextXid < catalog_xmin)
catalog_xmin_epoch --;
elog(DEBUG2, "sending hot standby feedback xmin %u epoch %u",
xmin, nextEpoch);
elog(DEBUG2, "sending hot standby feedback xmin %u epoch %u catalog_xmin %u catalog_xmin_epoch %u",
xmin, xmin_epoch, catalog_xmin, catalog_xmin_epoch);
/* Construct the message and send it. */
resetStringInfo(&reply_message);
pq_sendbyte(&reply_message, 'h');
pq_sendint64(&reply_message, GetCurrentTimestamp());
pq_sendint(&reply_message, xmin, 4);
pq_sendint(&reply_message, nextEpoch, 4);
pq_sendint(&reply_message, xmin_epoch, 4);
pq_sendint(&reply_message, catalog_xmin, 4);
pq_sendint(&reply_message, catalog_xmin_epoch, 4);
walrcv_send(wrconn, reply_message.data, reply_message.len);
if (TransactionIdIsValid(xmin))
if (TransactionIdIsValid(xmin) || TransactionIdIsValid(catalog_xmin))
master_has_standby_xmin = true;
else
master_has_standby_xmin = false;