pathman: concurrent config initialization issue fixed

zilder · zilder · commit 174bbc5ea63d · 2016-03-17T13:51:09.000+03:00
diff --git a/contrib/pg_pathman/dsm_array.c b/contrib/pg_pathman/dsm_array.c
@@ -79,9 +79,6 @@ init_dsm_segment(size_t blocks_count, size_t block_size)
 {
 	bool ret;
 
-	/* lock here */
-	LWLockAcquire(pmstate->dsm_init_lock, LW_EXCLUSIVE);
-
 	/* if there is already an existing segment then attach to it */
 	if (dsm_cfg->segment_handle != 0)
 	{
@@ -110,8 +107,6 @@ init_dsm_segment(size_t blocks_count, size_t block_size)
 	 * destroyed by the end of transaction
 	 */
 	dsm_pin_mapping(segment);
-	/* unlock here */
-	LWLockRelease(pmstate->dsm_init_lock);
 
 	return ret;
 }
diff --git a/contrib/pg_pathman/init.c b/contrib/pg_pathman/init.c
@@ -78,6 +78,8 @@ load_config(void)
 	Oid *databases;
 
 	initialization_needed = false;
+
+	LWLockAcquire(pmstate->dsm_init_lock, LW_EXCLUSIVE);
 	new_segment_created = init_dsm_segment(INITIAL_BLOCKS_COUNT, 32);
 
 	/* If dsm segment just created */
@@ -88,29 +90,22 @@ load_config(void)
 		 * oid into it. This array contains databases oids
 		 * that have already been cached (to prevent repeat caching)
 		 */
-		LWLockAcquire(pmstate->dsm_init_lock, LW_EXCLUSIVE);
-
 		if (&pmstate->databases.length > 0)
 			free_dsm_array(&pmstate->databases);
 		alloc_dsm_array(&pmstate->databases, sizeof(Oid), 1);
 		databases = (Oid *) dsm_array_get_pointer(&pmstate->databases);
 		databases[0] = MyDatabaseId;
-
-		LWLockRelease(pmstate->dsm_init_lock);
 	}
 	else
 	{
 		int databases_count = pmstate->databases.length;
 		int i;
 
 		/* Check if we already cached config for current database */
-		LWLockAcquire(pmstate->dsm_init_lock, LW_EXCLUSIVE);
-
 		databases = (Oid *) dsm_array_get_pointer(&pmstate->databases);
 		for(i=0; i<databases_count; i++)
 			if (databases[i] == MyDatabaseId)
 			{
-				// LWLockRelease(pmstate->load_config_lock);
 				LWLockRelease(pmstate->dsm_init_lock);
 				return;
 			}
@@ -119,14 +114,13 @@ load_config(void)
 		resize_dsm_array(&pmstate->databases, sizeof(Oid), databases_count + 1);
 		databases = (Oid *) dsm_array_get_pointer(&pmstate->databases);
 		databases[databases_count] = MyDatabaseId;
-
-		LWLockRelease(pmstate->dsm_init_lock);
 	}
 
 	/* Load cache */
 	LWLockAcquire(pmstate->load_config_lock, LW_EXCLUSIVE);
 	load_relations_hashtable(new_segment_created);
 	LWLockRelease(pmstate->load_config_lock);
+	LWLockRelease(pmstate->dsm_init_lock);
 }
 
 /*

Original file line number	Diff line number	Diff line change
`@@ -79,9 +79,6 @@ init_dsm_segment(size_t blocks_count, size_t block_size)`
`79`	`79`	`{`
`80`	`80`	`bool ret;`
`81`	`81`
`82`		`- /* lock here */`
`83`		`- LWLockAcquire(pmstate->dsm_init_lock, LW_EXCLUSIVE);`
`84`		`-`
`85`	`82`	`/* if there is already an existing segment then attach to it */`
`86`	`83`	`if (dsm_cfg->segment_handle != 0)`
`87`	`84`	`{`
`@@ -110,8 +107,6 @@ init_dsm_segment(size_t blocks_count, size_t block_size)`
`110`	`107`	`* destroyed by the end of transaction`
`111`	`108`	`*/`
`112`	`109`	`dsm_pin_mapping(segment);`
`113`		`- /* unlock here */`
`114`		`- LWLockRelease(pmstate->dsm_init_lock);`
`115`	`110`
`116`	`111`	`return ret;`
`117`	`112`	`}`