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/*-------------------------------------------------------------------------
*
* slotfuncs.c
* Support functions for replication slots
*
* Copyright (c) 2012-2014, PostgreSQL Global Development Group
*
* IDENTIFICATION
* src/backend/replication/slotfuncs.c
*
*-------------------------------------------------------------------------
*/
#include "postgres.h"
#include "funcapi.h"
#include "miscadmin.h"
#include "access/htup_details.h"
#include "utils/builtins.h"
#include "utils/pg_lsn.h"
#include "replication/slot.h"
Datum pg_create_physical_replication_slot(PG_FUNCTION_ARGS);
Datum pg_drop_replication_slot(PG_FUNCTION_ARGS);
static void
check_permissions(void)
{
if (!superuser() && !has_rolreplication(GetUserId()))
ereport(ERROR,
(errcode(ERRCODE_INSUFFICIENT_PRIVILEGE),
(errmsg("must be superuser or replication role to use replication slots"))));
}
/*
* SQL function for creating a new physical (streaming replication)
* replication slot.
*/
Datum
pg_create_physical_replication_slot(PG_FUNCTION_ARGS)
{
Name name = PG_GETARG_NAME(0);
Datum values[2];
bool nulls[2];
TupleDesc tupdesc;
HeapTuple tuple;
Datum result;
check_permissions();
CheckSlotRequirements();
if (get_call_result_type(fcinfo, NULL, &tupdesc) != TYPEFUNC_COMPOSITE)
elog(ERROR, "return type must be a row type");
/* acquire replication slot, this will check for conflicting names*/
ReplicationSlotCreate(NameStr(*name), false);
values[0] = NameGetDatum(&MyReplicationSlot->data.name);
nulls[0] = false;
nulls[1] = true;
tuple = heap_form_tuple(tupdesc, values, nulls);
result = HeapTupleGetDatum(tuple);
ReplicationSlotRelease();
PG_RETURN_DATUM(result);
}
/*
* SQL function for dropping a replication slot.
*/
Datum
pg_drop_replication_slot(PG_FUNCTION_ARGS)
{
Name name = PG_GETARG_NAME(0);
check_permissions();
CheckSlotRequirements();
ReplicationSlotDrop(NameStr(*name));
PG_RETURN_VOID();
}
/*
* pg_get_replication_slots - SQL SRF showing active replication slots.
*/
Datum
pg_get_replication_slots(PG_FUNCTION_ARGS)
{
#define PG_STAT_GET_REPLICATION_SLOTS_COLS 6
ReturnSetInfo *rsinfo = (ReturnSetInfo *) fcinfo->resultinfo;
TupleDesc tupdesc;
Tuplestorestate *tupstore;
MemoryContext per_query_ctx;
MemoryContext oldcontext;
int slotno;
/* 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");
/*
* We don't require any special permission to see this function's data
* because nothing should be sensitive. The most critical being the slot
* name, which shouldn't contain anything particularly sensitive.
*/
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 (slotno = 0; slotno < max_replication_slots; slotno++)
{
ReplicationSlot *slot = &ReplicationSlotCtl->replication_slots[slotno];
Datum values[PG_STAT_GET_REPLICATION_SLOTS_COLS];
bool nulls[PG_STAT_GET_REPLICATION_SLOTS_COLS];
TransactionId xmin;
XLogRecPtr restart_lsn;
bool active;
Oid database;
NameData slot_name;
int i;
SpinLockAcquire(&slot->mutex);
if (!slot->in_use)
{
SpinLockRelease(&slot->mutex);
continue;
}
else
{
xmin = slot->data.xmin;
database = slot->data.database;
restart_lsn = slot->data.restart_lsn;
namecpy(&slot_name, &slot->data.name);
active = slot->active;
}
SpinLockRelease(&slot->mutex);
memset(nulls, 0, sizeof(nulls));
i = 0;
values[i++] = NameGetDatum(&slot_name);
if (database == InvalidOid)
values[i++] = CStringGetTextDatum("physical");
else
values[i++] = CStringGetTextDatum("logical");
if (database == InvalidOid)
nulls[i++] = true;
else
values[i++] = database;
values[i++] = BoolGetDatum(active);
if (xmin != InvalidTransactionId)
values[i++] = TransactionIdGetDatum(xmin);
else
nulls[i++] = true;
if (restart_lsn != InvalidTransactionId)
values[i++] = LSNGetDatum(restart_lsn);
else
nulls[i++] = true;
tuplestore_putvalues(tupstore, tupdesc, values, nulls);
}
tuplestore_donestoring(tupstore);
return (Datum) 0;
}
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