/*
* _PG_init() - library load-time initialization
*
* DO NOT make this static nor change its name!
*/
void
_PG_init(void)
{
/* Be sure we do initialization only once (should be redundant now) */
static bool inited = false;
if (inited)
return;
pg_bindtextdomain(TEXTDOMAIN);
DefineCustomEnumVariable("plpgsql.variable_conflict",
gettext_noop("Sets handling of conflicts between PL/pgSQL variable names and table column names."),
NULL,
&plpgsql_variable_conflict,
PLPGSQL_RESOLVE_ERROR,
variable_conflict_options,
PGC_SUSET, 0,
NULL, NULL, NULL);
EmitWarningsOnPlaceholders("plpgsql");
plpgsql_HashTableInit();
RegisterXactCallback(plpgsql_xact_cb, NULL);
RegisterSubXactCallback(plpgsql_subxact_cb, NULL);
/* Set up a rendezvous point with optional instrumentation plugin */
plugin_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
inited = true;
}
static void DtmInitialize()
{
bool found;
static HASHCTL info;
LWLockAcquire(AddinShmemInitLock, LW_EXCLUSIVE);
dtm = ShmemInitStruct("dtm", sizeof(DtmState), &found);
if (!found)
{
dtm->hashLock = LWLockAssign();
dtm->xidLock = LWLockAssign();
dtm->nReservedXids = 0;
dtm->minXid = InvalidTransactionId;
dtm->nNodes = MMNodes;
dtm->disabledNodeMask = 0;
pg_atomic_write_u32(&dtm->nReceivers, 0);
dtm->initialized = false;
BgwPoolInit(&dtm->pool, MMExecutor, MMDatabaseName, MMQueueSize);
RegisterXactCallback(DtmXactCallback, NULL);
RegisterSubXactCallback(DtmSubXactCallback, NULL);
}
LWLockRelease(AddinShmemInitLock);
info.keysize = sizeof(TransactionId);
info.entrysize = sizeof(TransactionId);
info.hash = dtm_xid_hash_fn;
info.match = dtm_xid_match_fn;
xid_in_doubt = ShmemInitHash(
"xid_in_doubt",
DTM_HASH_SIZE, DTM_HASH_SIZE,
&info,
HASH_ELEM | HASH_FUNCTION | HASH_COMPARE
);
info.keysize = sizeof(TransactionId);
info.entrysize = sizeof(LocalTransaction);
info.hash = dtm_xid_hash_fn;
info.match = dtm_xid_match_fn;
local_trans = ShmemInitHash(
"local_trans",
DTM_HASH_SIZE, DTM_HASH_SIZE,
&info,
HASH_ELEM | HASH_FUNCTION | HASH_COMPARE
);
MMDoReplication = true;
TM = &DtmTM;
}
/*
* _PG_init() - library load-time initialization
*
* DO NOT make this static nor change its name!
*/
void
_PG_init(void)
{
/* Be sure we do initialization only once (should be redundant now) */
static bool inited = false;
if (inited)
return;
plpgsql_HashTableInit();
RegisterXactCallback(plpgsql_xact_cb, NULL);
RegisterSubXactCallback(plpgsql_subxact_cb, NULL);
/* Set up a rendezvous point with optional instrumentation plugin */
plugin_ptr = (PLpgSQL_plugin **) find_rendezvous_variable("PLpgSQL_plugin");
inited = true;
}
void
_PG_init()
{
HASHCTL ctl;
MemoryContext oldctx = MemoryContextSwitchTo(CacheMemoryContext);
Py_Initialize();
RegisterXactCallback(multicorn_xact_callback, NULL);
#if PG_VERSION_NUM >= 90300
RegisterSubXactCallback(multicorn_subxact_callback, NULL);
#endif
/* Initialize the global oid -> python instances hash */
MemSet(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(Oid);
ctl.entrysize = sizeof(CacheEntry);
ctl.hash = oid_hash;
ctl.hcxt = CacheMemoryContext;
InstancesHash = hash_create("multicorn instances", 32,
&ctl,
HASH_ELEM | HASH_FUNCTION);
MemoryContextSwitchTo(oldctx);
}
void
start_transaction(PlxConn *plx_conn)
{
int curlevel;
StringInfo sql = NULL;
if (!strcmp(plx_conn->plx_cluster->isolation_level, "auto commit"))
return;
curlevel = GetCurrentTransactionNestLevel();
if (!is_remote_transaction)
{
RegisterXactCallback(xact_callback, NULL);
RegisterSubXactCallback(subxact_callback, NULL);
is_remote_transaction = true;
}
if (plx_conn->xlevel == 0)
{
sql = makeStringInfo();
appendStringInfo(sql,
"start transaction isolation level %s;",
plx_conn->plx_cluster->isolation_level);
plx_conn->xlevel = 1;
}
while (plx_conn->xlevel < curlevel)
{
if (!sql)
sql = makeStringInfo();
appendStringInfo(sql, "savepoint s%d; ", (int) ++(plx_conn->xlevel));
is_remote_subtransaction = true;
}
if (sql)
PQclear(PQexec(plx_conn->pq_conn, sql->data));
}
/*
* Get a PGconn which can be used to execute queries on the remote PostgreSQL
* server with the user's authorization. A new connection is established
* if we don't already have a suitable one, and a transaction is opened at
* the right subtransaction nesting depth if we didn't do that already.
*
* will_prep_stmt must be true if caller intends to create any prepared
* statements. Since those don't go away automatically at transaction end
* (not even on error), we need this flag to cue manual cleanup.
*
* XXX Note that caching connections theoretically requires a mechanism to
* detect change of FDW objects to invalidate already established connections.
* We could manage that by watching for invalidation events on the relevant
* syscaches. For the moment, though, it's not clear that this would really
* be useful and not mere pedantry. We could not flush any active connections
* mid-transaction anyway.
*/
PGconn *
GetConnection(ForeignServer *server, UserMapping *user,
bool will_prep_stmt)
{
bool found;
ConnCacheEntry *entry;
ConnCacheKey key;
/* First time through, initialize connection cache hashtable */
if (ConnectionHash == NULL)
{
HASHCTL ctl;
MemSet(&ctl, 0, sizeof(ctl));
ctl.keysize = sizeof(ConnCacheKey);
ctl.entrysize = sizeof(ConnCacheEntry);
ctl.hash = tag_hash;
/* allocate ConnectionHash in the cache context */
ctl.hcxt = CacheMemoryContext;
ConnectionHash = hash_create("postgres_fdw connections", 8,
&ctl,
HASH_ELEM | HASH_FUNCTION | HASH_CONTEXT);
/*
* Register some callback functions that manage connection cleanup.
* This should be done just once in each backend.
*/
RegisterXactCallback(pgfdw_xact_callback, NULL);
RegisterSubXactCallback(pgfdw_subxact_callback, NULL);
}
/* Set flag that we did GetConnection during the current transaction */
xact_got_connection = true;
/* Create hash key for the entry. Assume no pad bytes in key struct */
key.serverid = server->serverid;
key.userid = user->userid;
/*
* Find or create cached entry for requested connection.
*/
entry = hash_search(ConnectionHash, &key, HASH_ENTER, &found);
if (!found)
{
/* initialize new hashtable entry (key is already filled in) */
entry->conn = NULL;
entry->xact_depth = 0;
entry->have_prep_stmt = false;
entry->have_error = false;
}
/*
* We don't check the health of cached connection here, because it would
* require some overhead. Broken connection will be detected when the
* connection is actually used.
*/
/*
* If cache entry doesn't have a connection, we have to establish a new
* connection. (If connect_pg_server throws an error, the cache entry
* will be left in a valid empty state.)
*/
if (entry->conn == NULL)
{
entry->xact_depth = 0; /* just to be sure */
entry->have_prep_stmt = false;
entry->have_error = false;
entry->conn = connect_pg_server(server, user);
elog(DEBUG3, "new postgres_fdw connection %p for server \"%s\"",
entry->conn, server->servername);
}
/*
* Start a new transaction or subtransaction if needed.
*/
begin_remote_xact(entry);
/* Remember if caller will prepare statements */
entry->have_prep_stmt |= will_prep_stmt;
return entry->conn;
}
