Function SessionState_Release

src/backend/utils/session_state.c:132–212

* Releases the pinCount of a SessionState entry. If the pinCount * drops to 0, it puts the entry back to the freeList for reuse. */

 * drops to 0, it puts the entry back to the freeList for reuse.
 */
static void
SessionState_Release(SessionState *acquired)
{
	if (!sessionStateInited)
	{
		Assert(NULL == acquired);
		return;
	}

	Assert(NULL != acquired);
	Assert(0 < acquired->pinCount);
	Assert(acquired->sessionId == gp_session_id || acquired->isModifiedSessionId);

	LWLockAcquire(SessionStateLock, LW_EXCLUSIVE);

	Assert(!isProcessActive);
	Assert(acquired->activeProcessCount < acquired->pinCount);

	int pinCount = pg_atomic_sub_fetch_u32((pg_atomic_uint32 *) &acquired->pinCount, 1);

	ereport(gp_sessionstate_loglevel, (errmsg("SessionState_Release: pinCount: %d, activeProcessCount: %d",
			pinCount, acquired->activeProcessCount), errprintstack(true)));

	    /* Before this point the process should have been deactivated */
	Assert(acquired->activeProcessCount <= acquired->pinCount);
	Assert(0 <= acquired->pinCount);

	if (0 == acquired->pinCount)
	{
		RunawayCleaner_RunawayCleanupDoneForSession();

		acquired->sessionId = INVALID_SESSION_ID;

		Assert(acquired->runawayStatus == RunawayStatus_NotRunaway);
		Assert(CLEANUP_COUNTDOWN_BEFORE_RUNAWAY == acquired->cleanupCountdown);
		Assert(0 == acquired->activeProcessCount);

		acquired->sessionVmem = 0;
		acquired->runawayStatus = RunawayStatus_NotRunaway;
		acquired->sessionVmemRunaway = 0;
		acquired->commandCountRunaway = 0;
		acquired->cleanupCountdown = CLEANUP_COUNTDOWN_BEFORE_RUNAWAY;
		acquired->activeProcessCount = 0;
		acquired->idle_start = 0;
		acquired->latestCursorCommandId = 0;
		acquired->resGroupSlot = NULL;

#ifdef USE_ASSERT_CHECKING
		acquired->isModifiedSessionId = false;
#endif

		SessionState *cur = AllSessionStateEntries->usedList;
		SessionState *prev = NULL;

		while (cur != acquired && cur != NULL)
		{
			prev = cur;
			cur = cur->next;