Spoc 384 (second part)

include/spock_group.h

@@ -151,16 +151,11 @@ extern void spock_group_shmem_request(void);
 extern void spock_group_shmem_startup(int napply_groups);
 
 SpockGroupEntry *spock_group_attach(Oid dbid, Oid node_id, Oid remote_node_id);
-void		spock_group_detach(void);
+extern void spock_group_detach(void);
 extern bool spock_group_progress_update(const SpockApplyProgress *sap);
 extern void spock_group_progress_update_ptr(SpockGroupEntry *entry,
 											const SpockApplyProgress *sap);
-SpockApplyProgress *apply_worker_get_progress(void);
-SpockGroupEntry *spock_group_lookup(Oid dbid, Oid node_id, Oid remote_node_id);
-
-/* Iterate all groups */
-typedef void (*SpockGroupIterCB) (const SpockGroupEntry *e, void *arg);
-void		spock_group_foreach(SpockGroupIterCB cb, void *arg);
+extern SpockApplyProgress *apply_worker_get_progress(void);
 
 extern void spock_group_resource_dump(void);
 extern void spock_checkpoint_hook(XLogRecPtr checkPointRedo, int flags);

src/spock_group.c

@@ -394,46 +394,45 @@ spock_group_progress_update_ptr(SpockGroupEntry *e,
 /*
  * apply_worker_get_progress
  *
- * Return a pointer to the current apply worker's progress payload, or NULL
+ * Return a pointer to the snapshot of the current apply worker's progress.
  */
 SpockApplyProgress *
 apply_worker_get_progress(void)
 {
+	static SpockApplyProgress sap;
+
 	Assert(MyApplyWorker != NULL);
 	Assert(MyApplyWorker->apply_group != NULL);
 
 	if (MyApplyWorker && MyApplyWorker->apply_group)
-		return &MyApplyWorker->apply_group->progress;
-
-	return NULL;
-}
+	{
+		LWLockAcquire(SpockCtx->apply_group_master_lock, LW_SHARED);
 
-/*
- * spock_group_lookup
- *
- * Snapshot-read the progress payload for the specified group. Uses HASH_FIND
- * to locate the entry.
- *
- * Returns entry if found, NULL otherwise.
- */
-SpockGroupEntry *
-spock_group_lookup(Oid dbid, Oid node_id, Oid remote_node_id)
-{
-	SpockGroupKey key = make_key(dbid, node_id, remote_node_id);
-	SpockGroupEntry *e;
+		memcpy(&sap, &MyApplyWorker->apply_group->progress,
+			   sizeof(SpockApplyProgress));
+		LWLockRelease(SpockCtx->apply_group_master_lock);
+	}
+	else
+		/*
+		 * Should never happen. In production just send the worker into
+		 * exception behaviour without crash.
+		 */
+		elog(ERROR, "apply worker has not been fully initialised yet");
 
-	e = (SpockGroupEntry *) hash_search(SpockGroupHash, &key, HASH_FIND, NULL);
-	return e;					/* may be NULL */
+	return &sap;
 }
 
+/* Iterate all groups */
+typedef void (*SpockGroupIterCB) (const SpockGroupEntry *e, void *arg);
+
 /*
  * spock_group_foreach
  *
  * Iterate all entries in the group hash and invoke 'cb(e, arg)' for each.
  * Caller selects any gating needed for consistency (e.g., take the gate in
  * SHARED before calling this if you want a coherent snapshot).
  */
-void
+static void
 spock_group_foreach(SpockGroupIterCB cb, void *arg)
 {
 	HASH_SEQ_STATUS it;