/*
* Returns activity of walsenders, including pids and xlog locations sent to
* standby servers.
*/
Datum
pg_stat_get_wal_senders(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_WAL_SENDERS_COLS 8
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
int *sync_priority;
int priority = 0;
int sync_standby = -1;
int i;
/* check to see if caller supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not " \
"allowed in this context")));
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tupstore = tuplestore_begin_heap(true, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
/*
* Get the priorities of sync standbys all in one go, to minimise lock
* acquisitions and to allow us to evaluate who is the current sync
* standby. This code must match the code in SyncRepReleaseWaiters().
*/
sync_priority = palloc(sizeof(int) * max_wal_senders);
LWLockAcquire(SyncRepLock, LW_SHARED);
for (i = 0; i < max_wal_senders; i++)
{
/* use volatile pointer to prevent code rearrangement */
volatile WalSnd *walsnd = &WalSndCtl->walsnds[i];
if (walsnd->pid != 0)
{
sync_priority[i] = walsnd->sync_standby_priority;
if (walsnd->state == WALSNDSTATE_STREAMING &&
walsnd->sync_standby_priority > 0 &&
(priority == 0 ||
priority > walsnd->sync_standby_priority))
{
priority = walsnd->sync_standby_priority;
sync_standby = i;
}
}
}
LWLockRelease(SyncRepLock);
for (i = 0; i < max_wal_senders; i++)
{
/* use volatile pointer to prevent code rearrangement */
volatile WalSnd *walsnd = &WalSndCtl->walsnds[i];
char location[MAXFNAMELEN];
XLogRecPtr sentPtr;
XLogRecPtr write;
XLogRecPtr flush;
XLogRecPtr apply;
WalSndState state;
Datum values[PG_STAT_GET_WAL_SENDERS_COLS];
bool nulls[PG_STAT_GET_WAL_SENDERS_COLS];
if (walsnd->pid == 0)
continue;
SpinLockAcquire(&walsnd->mutex);
sentPtr = walsnd->sentPtr;
state = walsnd->state;
write = walsnd->write;
flush = walsnd->flush;
apply = walsnd->apply;
SpinLockRelease(&walsnd->mutex);
memset(nulls, 0, sizeof(nulls));
values[0] = Int32GetDatum(walsnd->pid);
if (!superuser())
{
/*
* Only superusers can see details. Other users only get the pid
* value to know it's a walsender, but no details.
*/
MemSet(&nulls[1], true, PG_STAT_GET_WAL_SENDERS_COLS - 1);
}
else
{
values[1] = CStringGetTextDatum(WalSndGetStateString(state));
snprintf(location, sizeof(location), "%X/%X",
sentPtr.xlogid, sentPtr.xrecoff);
values[2] = CStringGetTextDatum(location);
if (write.xlogid == 0 && write.xrecoff == 0)
nulls[3] = true;
snprintf(location, sizeof(location), "%X/%X",
write.xlogid, write.xrecoff);
values[3] = CStringGetTextDatum(location);
if (flush.xlogid == 0 && flush.xrecoff == 0)
nulls[4] = true;
snprintf(location, sizeof(location), "%X/%X",
flush.xlogid, flush.xrecoff);
values[4] = CStringGetTextDatum(location);
if (apply.xlogid == 0 && apply.xrecoff == 0)
nulls[5] = true;
snprintf(location, sizeof(location), "%X/%X",
apply.xlogid, apply.xrecoff);
values[5] = CStringGetTextDatum(location);
values[6] = Int32GetDatum(sync_priority[i]);
/*
* More easily understood version of standby state. This is purely
* informational, not different from priority.
*/
if (sync_priority[i] == 0)
values[7] = CStringGetTextDatum("async");
else if (i == sync_standby)
values[7] = CStringGetTextDatum("sync");
else
values[7] = CStringGetTextDatum("potential");
}
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
}
pfree(sync_priority);
/* clean up and return the tuplestore */
tuplestore_donestoring(tupstore);
return (Datum) 0;
}
/*
* Returns activity of walsenders, including pids and xlog locations sent to
* standby servers.
*/
Datum
pg_stat_get_wal_senders(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_WAL_SENDERS_COLS 3
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
int i;
/* check to see if caller supports us returning a tuplestore */
if (rsinfo == NULL || !IsA(rsinfo, ReturnSetInfo))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("set-valued function called in context that cannot accept a set")));
if (!(rsinfo->allowedModes & SFRM_Materialize))
ereport(ERROR,
(errcode(ERRCODE_FEATURE_NOT_SUPPORTED),
errmsg("materialize mode required, but it is not " \
"allowed in this context")));
/* Build a tuple descriptor for our result type */
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
per_query_ctx = rsinfo->econtext->ecxt_per_query_memory;
oldcontext = MemoryContextSwitchTo(per_query_ctx);
tupstore = tuplestore_begin_heap(true, false, work_mem);
rsinfo->returnMode = SFRM_Materialize;
rsinfo->setResult = tupstore;
rsinfo->setDesc = tupdesc;
MemoryContextSwitchTo(oldcontext);
for (i = 0; i < max_wal_senders; i++)
{
/* use volatile pointer to prevent code rearrangement */
volatile WalSnd *walsnd = &WalSndCtl->walsnds[i];
char sent_location[MAXFNAMELEN];
XLogRecPtr sentPtr;
WalSndState state;
Datum values[PG_STAT_GET_WAL_SENDERS_COLS];
bool nulls[PG_STAT_GET_WAL_SENDERS_COLS];
if (walsnd->pid == 0)
continue;
SpinLockAcquire(&walsnd->mutex);
sentPtr = walsnd->sentPtr;
state = walsnd->state;
SpinLockRelease(&walsnd->mutex);
snprintf(sent_location, sizeof(sent_location), "%X/%X",
sentPtr.xlogid, sentPtr.xrecoff);
memset(nulls, 0, sizeof(nulls));
values[0] = Int32GetDatum(walsnd->pid);
if (!superuser())
{
/*
* Only superusers can see details. Other users only get
* the pid value to know it's a walsender, but no details.
*/
nulls[1] = true;
nulls[2] = true;
}
else
{
values[1] = CStringGetTextDatum(WalSndGetStateString(state));
values[2] = CStringGetTextDatum(sent_location);
}
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
}
/* clean up and return the tuplestore */
tuplestore_donestoring(tupstore);
return (Datum) 0;
}
