/*
* pg_lock_status - produce a view with one row per held or awaited lock mode
*/
Datum
pg_lock_status(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
PG_Lock_Status *mystatus;
LockData *lockData;
PredicateLockData *predLockData;
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc;
MemoryContext oldcontext;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* build tupdesc for result tuples */
/* this had better match pg_locks view in system_views.sql */
tupdesc = CreateTemplateTupleDesc(NUM_LOCK_STATUS_COLUMNS, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "locktype",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "database",
OIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relation",
OIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 4, "page",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 5, "tuple",
INT2OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 6, "virtualxid",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 7, "transactionid",
XIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 8, "classid",
OIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 9, "objid",
OIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 10, "objsubid",
INT2OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 11, "virtualtransaction",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 12, "pid",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 13, "mode",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 14, "granted",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 15, "fastpath",
BOOLOID, -1, 0);
funcctx->tuple_desc = BlessTupleDesc(tupdesc);
/*
* Collect all the locking information that we will format and send
* out as a result set.
*/
mystatus = (PG_Lock_Status *) palloc(sizeof(PG_Lock_Status));
funcctx->user_fctx = (void *) mystatus;
mystatus->lockData = GetLockStatusData();
mystatus->currIdx = 0;
mystatus->predLockData = GetPredicateLockStatusData();
mystatus->predLockIdx = 0;
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
mystatus = (PG_Lock_Status *) funcctx->user_fctx;
lockData = mystatus->lockData;
while (mystatus->currIdx < lockData->nelements)
{
bool granted;
LOCKMODE mode = 0;
const char *locktypename;
char tnbuf[32];
Datum values[NUM_LOCK_STATUS_COLUMNS];
bool nulls[NUM_LOCK_STATUS_COLUMNS];
HeapTuple tuple;
Datum result;
LockInstanceData *instance;
instance = &(lockData->locks[mystatus->currIdx]);
/*
* Look to see if there are any held lock modes in this PROCLOCK. If
* so, report, and destructively modify lockData so we don't report
* again.
*/
granted = false;
if (instance->holdMask)
{
for (mode = 0; mode < MAX_LOCKMODES; mode++)
{
if (instance->holdMask & LOCKBIT_ON(mode))
{
granted = true;
instance->holdMask &= LOCKBIT_OFF(mode);
break;
}
}
}
/*
* If no (more) held modes to report, see if PROC is waiting for a
* lock on this lock.
*/
if (!granted)
{
if (instance->waitLockMode != NoLock)
{
/* Yes, so report it with proper mode */
mode = instance->waitLockMode;
/*
* We are now done with this PROCLOCK, so advance pointer to
* continue with next one on next call.
*/
mystatus->currIdx++;
}
else
{
/*
* Okay, we've displayed all the locks associated with this
* PROCLOCK, proceed to the next one.
*/
mystatus->currIdx++;
continue;
}
}
/*
* Form tuple with appropriate data.
*/
MemSet(values, 0, sizeof(values));
MemSet(nulls, false, sizeof(nulls));
if (instance->locktag.locktag_type <= LOCKTAG_LAST_TYPE)
locktypename = LockTagTypeNames[instance->locktag.locktag_type];
else
{
snprintf(tnbuf, sizeof(tnbuf), "unknown %d",
(int) instance->locktag.locktag_type);
locktypename = tnbuf;
}
values[0] = CStringGetTextDatum(locktypename);
switch ((LockTagType) instance->locktag.locktag_type)
{
case LOCKTAG_RELATION:
case LOCKTAG_RELATION_EXTEND:
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_PAGE:
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
values[3] = UInt32GetDatum(instance->locktag.locktag_field3);
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_TUPLE:
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
values[3] = UInt32GetDatum(instance->locktag.locktag_field3);
values[4] = UInt16GetDatum(instance->locktag.locktag_field4);
nulls[5] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_TRANSACTION:
values[6] =
TransactionIdGetDatum(instance->locktag.locktag_field1);
nulls[1] = true;
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_VIRTUALTRANSACTION:
values[5] = VXIDGetDatum(instance->locktag.locktag_field1,
instance->locktag.locktag_field2);
nulls[1] = true;
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_OBJECT:
case LOCKTAG_USERLOCK:
case LOCKTAG_ADVISORY:
default: /* treat unknown locktags like OBJECT */
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[7] = ObjectIdGetDatum(instance->locktag.locktag_field2);
values[8] = ObjectIdGetDatum(instance->locktag.locktag_field3);
values[9] = Int16GetDatum(instance->locktag.locktag_field4);
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
break;
}
values[10] = VXIDGetDatum(instance->backend, instance->lxid);
if (instance->pid != 0)
values[11] = Int32GetDatum(instance->pid);
else
nulls[11] = true;
values[12] = CStringGetTextDatum(GetLockmodeName(instance->locktag.locktag_lockmethodid, mode));
values[13] = BoolGetDatum(granted);
values[14] = BoolGetDatum(instance->fastpath);
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
/*
* Have returned all regular locks. Now start on the SIREAD predicate
* locks.
*/
predLockData = mystatus->predLockData;
if (mystatus->predLockIdx < predLockData->nelements)
{
PredicateLockTargetType lockType;
PREDICATELOCKTARGETTAG *predTag = &(predLockData->locktags[mystatus->predLockIdx]);
SERIALIZABLEXACT *xact = &(predLockData->xacts[mystatus->predLockIdx]);
Datum values[NUM_LOCK_STATUS_COLUMNS];
bool nulls[NUM_LOCK_STATUS_COLUMNS];
HeapTuple tuple;
Datum result;
mystatus->predLockIdx++;
/*
* Form tuple with appropriate data.
*/
MemSet(values, 0, sizeof(values));
MemSet(nulls, false, sizeof(nulls));
/* lock type */
lockType = GET_PREDICATELOCKTARGETTAG_TYPE(*predTag);
values[0] = CStringGetTextDatum(PredicateLockTagTypeNames[lockType]);
/* lock target */
values[1] = GET_PREDICATELOCKTARGETTAG_DB(*predTag);
values[2] = GET_PREDICATELOCKTARGETTAG_RELATION(*predTag);
if (lockType == PREDLOCKTAG_TUPLE)
values[4] = GET_PREDICATELOCKTARGETTAG_OFFSET(*predTag);
else
nulls[4] = true;
if ((lockType == PREDLOCKTAG_TUPLE) ||
(lockType == PREDLOCKTAG_PAGE))
values[3] = GET_PREDICATELOCKTARGETTAG_PAGE(*predTag);
else
nulls[3] = true;
/* these fields are targets for other types of locks */
nulls[5] = true; /* virtualxid */
nulls[6] = true; /* transactionid */
nulls[7] = true; /* classid */
nulls[8] = true; /* objid */
nulls[9] = true; /* objsubid */
/* lock holder */
values[10] = VXIDGetDatum(xact->vxid.backendId,
xact->vxid.localTransactionId);
if (xact->pid != 0)
values[11] = Int32GetDatum(xact->pid);
else
nulls[11] = true;
/*
* Lock mode. Currently all predicate locks are SIReadLocks, which are
* always held (never waiting) and have no fast path
*/
values[12] = CStringGetTextDatum("SIReadLock");
values[13] = BoolGetDatum(true);
values[14] = BoolGetDatum(false);
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
SRF_RETURN_DONE(funcctx);
}
/*
* pg_lock_status - produce a view with one row per held or awaited lock mode
*/
Datum
pg_lock_status(PG_FUNCTION_ARGS)
{
FuncCallContext *funcctx;
PG_Lock_Status *mystatus;
LockData *lockData;
PredicateLockData *predLockData;
if (SRF_IS_FIRSTCALL())
{
TupleDesc tupdesc;
MemoryContext oldcontext;
/* create a function context for cross-call persistence */
funcctx = SRF_FIRSTCALL_INIT();
/*
* switch to memory context appropriate for multiple function calls
*/
oldcontext = MemoryContextSwitchTo(funcctx->multi_call_memory_ctx);
/* build tupdesc for result tuples */
/* this had better match pg_locks view in system_views.sql */
tupdesc = CreateTemplateTupleDesc(NUM_LOCK_STATUS_COLUMNS, false);
TupleDescInitEntry(tupdesc, (AttrNumber) 1, "locktype",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 2, "database",
OIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 3, "relation",
OIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 4, "page",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 5, "tuple",
INT2OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 6, "virtualxid",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 7, "transactionid",
XIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 8, "classid",
OIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 9, "objid",
OIDOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 10, "objsubid",
INT2OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 11, "virtualtransaction",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 12, "pid",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 13, "mode",
TEXTOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 14, "granted",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 15, "fastpath",
BOOLOID, -1, 0);
/*
* These next columns are specific to GPDB
*/
TupleDescInitEntry(tupdesc, (AttrNumber) 16, "mppSessionId",
INT4OID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 17, "mppIsWriter",
BOOLOID, -1, 0);
TupleDescInitEntry(tupdesc, (AttrNumber) 18, "gp_segment_id",
INT4OID, -1, 0);
funcctx->tuple_desc = BlessTupleDesc(tupdesc);
/*
* Collect all the locking information that we will format and send
* out as a result set.
*/
mystatus = (PG_Lock_Status *) palloc(sizeof(PG_Lock_Status));
funcctx->user_fctx = (void *) mystatus;
mystatus->lockData = GetLockStatusData();
mystatus->currIdx = 0;
mystatus->predLockData = GetPredicateLockStatusData();
mystatus->predLockIdx = 0;
mystatus->numSegLocks = 0;
mystatus->numsegresults = 0;
mystatus->segresults = NULL;
/*
* Seeing the locks just from the masterDB isn't enough to know what is locked,
* or if there is a deadlock. That's because the segDBs also take locks.
* Some locks show up only on the master, some only on the segDBs, and some on both.
*
* So, let's collect the lock information from all the segDBs. Sure, this means
* there are a lot more rows coming back from pg_locks than before, since most locks
* on the segDBs happen across all the segDBs at the same time. But not always,
* so let's play it safe and get them all.
*/
if (Gp_role == GP_ROLE_DISPATCH)
{
CdbPgResults cdb_pgresults = {NULL, 0};
StringInfoData buffer;
int i;
initStringInfo(&buffer);
/*
* Why dispatch something here, rather than do a UNION ALL in pg_locks view, and
* a join to gp_dist_random('gp_id')? There are several important reasons.
*
* The union all method is much slower, and requires taking locks on gp_id.
* More importantly, applications such as pgAdmin do queries of this view that
* involve a correlated subqueries joining to other catalog tables,
* which works if we do it this way, but fails
* if the view includes the union all. That completely breaks the server status
* display in pgAdmin.
*
* Why dispatch this way, rather than via SPI? There are several advantages.
* First, it's easy to get "writer gang is busy" errors if we use SPI.
*
* Second, this should be much faster, as it doesn't require setting up
* the interconnect, and doesn't need to touch any actual data tables to be
* able to get the gp_segment_id.
*
* The downside is we get n result sets, where n == number of segDBs.
*
* It would be better yet if we sent a plan tree rather than a text string,
* so the segDBs don't need to parse it. That would also avoid taking any relation locks
* on the segDB to get this info (normally need to get an accessShareLock on pg_locks on the segDB
* to make sure it doesn't go away during parsing). But the only safe way I know to do this
* is to hand-build the plan tree, and I'm to lazy to do it right now. It's just a matter of
* building a function scan node, and filling it in with our result set info (from the tupledesc).
*
* One thing to note: it's OK to join pg_locks with any catalog table or master-only table,
* but joining to a distributed table will result in "writer gang busy: possible attempt to
* execute volatile function in unsupported context" errors, because
* the scan of the distributed table might already be running on the writer gang
* when we want to dispatch this.
*
* This could be fixed by allocating a reader gang and dispatching to that, but the cost
* of setting up a new gang is high, and I've never seen anyone need to join this to a
* distributed table.
*
* GPDB_84_MERGE_FIXME: Should we rewrite this in a different way now that we have
* ON SEGMENT/ ON MASTER attributes on functions?
*/
CdbDispatchCommand("SELECT * FROM pg_catalog.pg_lock_status()", DF_WITH_SNAPSHOT, &cdb_pgresults);
if (cdb_pgresults.numResults == 0)
elog(ERROR, "pg_locks didn't get back any data from the segDBs");
for (i = 0; i < cdb_pgresults.numResults; i++)
{
/*
* Any error here should have propagated into errbuf, so we shouldn't
* ever see anything other that tuples_ok here. But, check to be
* sure.
*/
if (PQresultStatus(cdb_pgresults.pg_results[i]) != PGRES_TUPLES_OK)
{
cdbdisp_clearCdbPgResults(&cdb_pgresults);
elog(ERROR,"pg_locks: resultStatus not tuples_Ok");
}
/*
* numSegLocks needs to be the total size we are returning to
* the application. At the start of this loop, it has the count
* for the masterDB locks. Add each of the segDB lock counts.
*/
mystatus->numSegLocks += PQntuples(cdb_pgresults.pg_results[i]);
/*
* This query better match the tupledesc we just made above.
*/
if (PQnfields(cdb_pgresults.pg_results[i]) != tupdesc->natts)
elog(ERROR, "unexpected number of columns returned from pg_lock_status() on segment (%d, expected %d)",
PQnfields(cdb_pgresults.pg_results[i]), tupdesc->natts);
}
mystatus->numsegresults = cdb_pgresults.numResults;
/*
* cdbdisp_dispatchRMCommand copies the result sets into our memory, which
* will still exist on the subsequent calls.
*/
mystatus->segresults = cdb_pgresults.pg_results;
}
MemoryContextSwitchTo(oldcontext);
}
funcctx = SRF_PERCALL_SETUP();
mystatus = (PG_Lock_Status *) funcctx->user_fctx;
lockData = mystatus->lockData;
/*
* This loop returns all the local lock data from the segment we are running on.
*/
while (mystatus->currIdx < lockData->nelements)
{
bool granted;
LOCKMODE mode = 0;
const char *locktypename;
char tnbuf[32];
Datum values[NUM_LOCK_STATUS_COLUMNS];
bool nulls[NUM_LOCK_STATUS_COLUMNS];
HeapTuple tuple;
Datum result;
LockInstanceData *instance;
instance = &(lockData->locks[mystatus->currIdx]);
/*
* Look to see if there are any held lock modes in this PROCLOCK. If
* so, report, and destructively modify lockData so we don't report
* again.
*/
granted = false;
if (instance->holdMask)
{
for (mode = 0; mode < MAX_LOCKMODES; mode++)
{
if (instance->holdMask & LOCKBIT_ON(mode))
{
granted = true;
instance->holdMask &= LOCKBIT_OFF(mode);
break;
}
}
}
/*
* If no (more) held modes to report, see if PROC is waiting for a
* lock on this lock.
*/
if (!granted)
{
if (instance->waitLockMode != NoLock)
{
/* Yes, so report it with proper mode */
mode = instance->waitLockMode;
/*
* We are now done with this PROCLOCK, so advance pointer to
* continue with next one on next call.
*/
mystatus->currIdx++;
}
else
{
/*
* Okay, we've displayed all the locks associated with this
* PROCLOCK, proceed to the next one.
*/
mystatus->currIdx++;
continue;
}
}
/*
* Form tuple with appropriate data.
*/
MemSet(values, 0, sizeof(values));
MemSet(nulls, false, sizeof(nulls));
if (instance->locktag.locktag_type <= LOCKTAG_LAST_TYPE)
locktypename = LockTagTypeNames[instance->locktag.locktag_type];
else
{
snprintf(tnbuf, sizeof(tnbuf), "unknown %d",
(int) instance->locktag.locktag_type);
locktypename = tnbuf;
}
values[0] = CStringGetTextDatum(locktypename);
switch ((LockTagType) instance->locktag.locktag_type)
{
case LOCKTAG_RELATION:
case LOCKTAG_RELATION_EXTEND:
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_PAGE:
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
values[3] = UInt32GetDatum(instance->locktag.locktag_field3);
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_TUPLE:
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
values[3] = UInt32GetDatum(instance->locktag.locktag_field3);
values[4] = UInt16GetDatum(instance->locktag.locktag_field4);
nulls[5] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_TRANSACTION:
values[6] =
TransactionIdGetDatum(instance->locktag.locktag_field1);
nulls[1] = true;
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_VIRTUALTRANSACTION:
values[5] = VXIDGetDatum(instance->locktag.locktag_field1,
instance->locktag.locktag_field2);
nulls[1] = true;
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[6] = true;
nulls[7] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_RELATION_APPENDONLY_SEGMENT_FILE:
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[2] = ObjectIdGetDatum(instance->locktag.locktag_field2);
values[7] = ObjectIdGetDatum(instance->locktag.locktag_field3);
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
nulls[8] = true;
nulls[9] = true;
break;
case LOCKTAG_RESOURCE_QUEUE:
#if 0
values[1] = ObjectIdGetDatum(proc->databaseId);
#endif
nulls[1] = true;
values[8] = ObjectIdGetDatum(instance->locktag.locktag_field1);
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
nulls[7] = true;
nulls[9] = true;
break;
case LOCKTAG_OBJECT:
case LOCKTAG_USERLOCK:
case LOCKTAG_ADVISORY:
default: /* treat unknown locktags like OBJECT */
values[1] = ObjectIdGetDatum(instance->locktag.locktag_field1);
values[7] = ObjectIdGetDatum(instance->locktag.locktag_field2);
values[8] = ObjectIdGetDatum(instance->locktag.locktag_field3);
values[9] = Int16GetDatum(instance->locktag.locktag_field4);
nulls[2] = true;
nulls[3] = true;
nulls[4] = true;
nulls[5] = true;
nulls[6] = true;
break;
}
values[10] = VXIDGetDatum(instance->backend, instance->lxid);
if (instance->pid != 0)
values[11] = Int32GetDatum(instance->pid);
else
nulls[11] = true;
values[12] = CStringGetTextDatum(GetLockmodeName(instance->locktag.locktag_lockmethodid, mode));
values[13] = BoolGetDatum(granted);
values[14] = BoolGetDatum(instance->fastpath);
values[15] = Int32GetDatum(instance->mppSessionId);
values[16] = BoolGetDatum(instance->mppIsWriter);
values[17] = Int32GetDatum(GpIdentity.segindex);
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
/*
* This loop only executes on the masterDB and only in dispatch mode, because that
* is the only time we dispatched to the segDBs.
*/
while (mystatus->currIdx >= lockData->nelements && mystatus->currIdx < lockData->nelements + mystatus->numSegLocks)
{
HeapTuple tuple;
Datum result;
Datum values[NUM_LOCK_STATUS_COLUMNS];
bool nulls[NUM_LOCK_STATUS_COLUMNS];
int i;
int whichresultset = 0;
int whichelement = mystatus->currIdx - lockData->nelements;
int whichrow = whichelement;
Assert(Gp_role == GP_ROLE_DISPATCH);
/*
* Because we have one result set per segDB (rather than one big result set with everything),
* we need to figure out which result set we are on, and which row within that result set
* we are returning.
*
* So, we walk through all the result sets and all the rows in each one, in order.
*/
while(whichrow >= PQntuples(mystatus->segresults[whichresultset]))
{
whichrow -= PQntuples(mystatus->segresults[whichresultset]);
whichresultset++;
if (whichresultset >= mystatus->numsegresults)
break;
}
/*
* If this condition is true, we have already sent everything back,
* and we just want to do the SRF_RETURN_DONE
*/
if (whichresultset >= mystatus->numsegresults)
break;
mystatus->currIdx++;
/*
* Form tuple with appropriate data we got from the segDBs
*/
MemSet(values, 0, sizeof(values));
MemSet(nulls, false, sizeof(nulls));
/*
* For each column, extract out the value (which comes out in text).
* Convert it to the appropriate datatype to match our tupledesc,
* and put that in values.
* The columns look like this (from select statement earlier):
*
* " (locktype text, database oid, relation oid, page int4, tuple int2,"
* " transactionid xid, classid oid, objid oid, objsubid int2,"
* " transaction xid, pid int4, mode text, granted boolean, "
* " mppSessionId int4, mppIsWriter boolean, gp_segment_id int4) ,"
*/
values[0] = CStringGetTextDatum(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 0));
values[1] = ObjectIdGetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 1)));
values[2] = ObjectIdGetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 2)));
values[3] = UInt32GetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 3)));
values[4] = UInt16GetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 4)));
values[5] = CStringGetTextDatum(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 5));
values[6] = TransactionIdGetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 6)));
values[7] = ObjectIdGetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 7)));
values[8] = ObjectIdGetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 8)));
values[9] = UInt16GetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 9)));
values[10] = CStringGetTextDatum(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 10));
values[11] = UInt32GetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 11)));
values[12] = CStringGetTextDatum(PQgetvalue(mystatus->segresults[whichresultset], whichrow, 12));
values[13] = BoolGetDatum(strncmp(PQgetvalue(mystatus->segresults[whichresultset], whichrow,13),"t",1)==0);
values[14] = BoolGetDatum(strncmp(PQgetvalue(mystatus->segresults[whichresultset], whichrow,14),"t",1)==0);
values[15] = Int32GetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow,15)));
values[16] = BoolGetDatum(strncmp(PQgetvalue(mystatus->segresults[whichresultset], whichrow,16),"t",1)==0);
values[17] = Int32GetDatum(atoi(PQgetvalue(mystatus->segresults[whichresultset], whichrow,17)));
/*
* Copy the null info over. It should all match properly.
*/
for (i = 0; i < NUM_LOCK_STATUS_COLUMNS; i++)
{
nulls[i] = PQgetisnull(mystatus->segresults[whichresultset], whichrow, i);
}
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
/*
* Have returned all regular locks. Now start on the SIREAD predicate
* locks.
*/
predLockData = mystatus->predLockData;
if (mystatus->predLockIdx < predLockData->nelements)
{
PredicateLockTargetType lockType;
PREDICATELOCKTARGETTAG *predTag = &(predLockData->locktags[mystatus->predLockIdx]);
SERIALIZABLEXACT *xact = &(predLockData->xacts[mystatus->predLockIdx]);
Datum values[NUM_LOCK_STATUS_COLUMNS];
bool nulls[NUM_LOCK_STATUS_COLUMNS];
HeapTuple tuple;
Datum result;
mystatus->predLockIdx++;
/*
* Form tuple with appropriate data.
*/
MemSet(values, 0, sizeof(values));
MemSet(nulls, false, sizeof(nulls));
/* lock type */
lockType = GET_PREDICATELOCKTARGETTAG_TYPE(*predTag);
values[0] = CStringGetTextDatum(PredicateLockTagTypeNames[lockType]);
/* lock target */
values[1] = GET_PREDICATELOCKTARGETTAG_DB(*predTag);
values[2] = GET_PREDICATELOCKTARGETTAG_RELATION(*predTag);
if (lockType == PREDLOCKTAG_TUPLE)
values[4] = GET_PREDICATELOCKTARGETTAG_OFFSET(*predTag);
else
nulls[4] = true;
if ((lockType == PREDLOCKTAG_TUPLE) ||
(lockType == PREDLOCKTAG_PAGE))
values[3] = GET_PREDICATELOCKTARGETTAG_PAGE(*predTag);
else
nulls[3] = true;
/* these fields are targets for other types of locks */
nulls[5] = true; /* virtualxid */
nulls[6] = true; /* transactionid */
nulls[7] = true; /* classid */
nulls[8] = true; /* objid */
nulls[9] = true; /* objsubid */
/* lock holder */
values[10] = VXIDGetDatum(xact->vxid.backendId,
xact->vxid.localTransactionId);
if (xact->pid != 0)
values[11] = Int32GetDatum(xact->pid);
else
nulls[11] = true;
/*
* Lock mode. Currently all predicate locks are SIReadLocks, which are
* always held (never waiting) and have no fast path
*/
values[12] = CStringGetTextDatum("SIReadLock");
values[13] = BoolGetDatum(true);
values[14] = BoolGetDatum(false);
/*
* GPDB_91_MERGE_FIXME: what to set these GPDB-specific fields to?
* These commented-out values are copy-pasted from the code above
* for normal locks.
*/
//values[14] = Int32GetDatum(proc->mppSessionId);
//values[15] = BoolGetDatum(proc->mppIsWriter);
//values[16] = Int32GetDatum(Gp_segment);
tuple = heap_form_tuple(funcctx->tuple_desc, values, nulls);
result = HeapTupleGetDatum(tuple);
SRF_RETURN_NEXT(funcctx, result);
}
/*
* if we dispatched to the segDBs, free up the memory holding the result sets.
* Otherwise we might leak this memory each time we got called (does it automatically
* get freed by the pool being deleted? Probably, but this is safer).
*/
if (mystatus->segresults != NULL)
{
int i;
for (i = 0; i < mystatus->numsegresults; i++)
PQclear(mystatus->segresults[i]);
free(mystatus->segresults);
}
SRF_RETURN_DONE(funcctx);
}
