ADBDEV-4648: Limit diskquota hash table's size according initial request

src/diskquota.c

@@ -70,14 +70,16 @@ static volatile sig_atomic_t got_sigusr1 = false;
 static volatile sig_atomic_t got_sigusr2 = false;
 
 /* GUC variables */
-int  diskquota_naptime                 = 0;
-int  diskquota_max_active_tables       = 0;
-int  diskquota_worker_timeout          = 60; /* default timeout is 60 seconds */
-bool diskquota_hardlimit               = false;
-int  diskquota_max_workers             = 10;
-int  diskquota_max_table_segments      = 0;
-int  diskquota_max_monitored_databases = 0;
-int  diskquota_max_quota_probes        = 0;
+int  diskquota_naptime                         = 0;
+int  diskquota_max_active_tables               = 0;
+int  diskquota_worker_timeout                  = 60; /* default timeout is 60 seconds */
+bool diskquota_hardlimit                       = false;
+int  diskquota_max_workers                     = 10;
+int  diskquota_max_table_segments              = 0;
+int  diskquota_max_monitored_databases         = 0;
+int  diskquota_max_quota_probes                = 0;
+int  diskquota_max_local_reject_entries        = 0;
+int  diskquota_hashmap_overflow_report_timeout = 0;
 
 DiskQuotaLocks       diskquota_locks;
 ExtensionDDLMessage *extension_ddl_message = NULL;
@@ -89,12 +91,6 @@ static DiskQuotaWorkerEntry *volatile MyWorkerInfo = NULL;
 // how many database diskquota are monitoring on
 static int num_db = 0;
 
-/* how many TableSizeEntry are maintained in all the table_size_map in shared memory*/
-pg_atomic_uint32 *diskquota_table_size_entry_num;
-
-/* how many QuotaInfoEntry are maintained in all the quota_info_map in shared memory*/
-pg_atomic_uint32 *diskquota_quota_info_entry_num;
-
 static DiskquotaLauncherShmemStruct *DiskquotaLauncherShmem;
 
 #define MIN_SLEEPTIME 100         /* milliseconds */
@@ -414,6 +410,12 @@ define_guc_variables(void)
 	DefineCustomIntVariable("diskquota.max_quota_probes", "Max number of quotas on the cluster.", NULL,
 	                        &diskquota_max_quota_probes, 1024 * 1024, 1024 * INIT_QUOTA_MAP_ENTRIES, INT_MAX,
 	                        PGC_POSTMASTER, 0, NULL, NULL, NULL);
+	DefineCustomIntVariable("diskquota.max_reject_entries", "Max number of reject entries per database.", NULL,
+	                        &diskquota_max_local_reject_entries, 8192, 1, INT_MAX, PGC_POSTMASTER, 0, NULL, NULL, NULL);
+	DefineCustomIntVariable("diskquota.hashmap_overflow_report_timeout",
+	                        "The duration between each warning report about the shared hashmap overflow (in seconds).",
+	                        NULL, &diskquota_hashmap_overflow_report_timeout, 60, 0, INT_MAX / 1000, PGC_SUSET, 0, NULL,
+	                        NULL, NULL);
 }
 
 /* ---- Functions for disk quota worker process ---- */
@@ -1802,15 +1804,6 @@ init_launcher_shmem()
 			DiskquotaLauncherShmem->dbArray[i].workerId = INVALID_WORKER_ID;
 		}
 	}
-	/* init TableSizeEntry counter */
-	diskquota_table_size_entry_num =
-	        ShmemInitStruct("diskquota TableSizeEntry counter", sizeof(pg_atomic_uint32), &found);
-	if (!found) pg_atomic_init_u32(diskquota_table_size_entry_num, 0);
-
-	/* init QuotaInfoEntry counter */
-	diskquota_quota_info_entry_num =
-	        ShmemInitStruct("diskquota QuotaInfoEntry counter", sizeof(pg_atomic_uint32), &found);
-	if (!found) pg_atomic_init_u32(diskquota_quota_info_entry_num, 0);
 }
 
 /*

src/diskquota.h

@@ -286,6 +286,7 @@ extern Datum diskquota_fetch_table_stat(PG_FUNCTION_ARGS);
 extern int   diskquota_naptime;
 extern int   diskquota_max_active_tables;
 extern bool  diskquota_hardlimit;
+extern int   diskquota_hashmap_overflow_report_timeout;
 
 extern int      SEGCOUNT;
 extern int      worker_spi_get_extension_version(int *major, int *minor);
@@ -316,4 +317,6 @@ extern HTAB        *diskquota_hash_create(const char *tabname, long nelem, HASHC
 extern HTAB *DiskquotaShmemInitHash(const char *name, long init_size, long max_size, HASHCTL *infoP, int hash_flags,
                                     DiskquotaHashFunction hash_function);
 extern void  refresh_monitored_dbid_cache(void);
+extern HASHACTION check_hash_fullness(HTAB *hashp, int max_size, const char *warning_message,
+                                      TimestampTz *last_overflow_report);
 #endif

src/diskquota_utility.c

@@ -1683,3 +1683,29 @@ DiskquotaShmemInitHash(const char           *name,       /* table string name fo
 	return ShmemInitHash(name, init_size, max_size, infoP, hash_flags | HASH_BLOBS);
 #endif /* GP_VERSION_NUM */
 }
+
+/*
+ * Returns HASH_FIND if hash table is full and HASH_ENTER otherwise.
+ * It can be used only under lock.
+ */
+HASHACTION
+check_hash_fullness(HTAB *hashp, int max_size, const char *warning_message, TimestampTz *last_overflow_report)
+{
+	long num_entries = hash_get_num_entries(hashp);
+
+	if (num_entries < max_size) return HASH_ENTER;
+
+	if (num_entries == max_size)
+	{
+		TimestampTz current_time = GetCurrentTimestamp();
+
+		if (*last_overflow_report == 0 || TimestampDifferenceExceeds(*last_overflow_report, current_time,
+		                                                             diskquota_hashmap_overflow_report_timeout * 1000))
+		{
+			ereport(WARNING, (errmsg("[diskquota] %s", warning_message)));
+			*last_overflow_report = current_time;
+		}
+	}
+
+	return HASH_FIND;
+}

src/gp_activetable.c

@@ -51,7 +51,12 @@ typedef struct DiskQuotaSetOFCache
 	HASH_SEQ_STATUS pos;
 } DiskQuotaSetOFCache;
 
-HTAB *active_tables_map = NULL; // Set<DiskQuotaActiveTableFileEntry>
+static HTAB *active_tables_map                      = NULL; // Set<DiskQuotaActiveTableFileEntry>
+TimestampTz  active_tables_map_last_overflow_report = 0;
+
+static const char *active_tables_map_warning =
+        "the number of active tables reached the limit, please increase "
+        "the GUC value for diskquota.max_active_tables.";
 
 /*
  * monitored_dbid_cache is a allow list for diskquota
@@ -60,7 +65,12 @@ HTAB *active_tables_map = NULL; // Set<DiskQuotaActiveTableFileEntry>
  * dbid will be added to it when creating diskquota extension
  * dbid will be removed from it when droping diskquota extension
  */
-HTAB *altered_reloid_cache = NULL; // Set<Oid>
+static HTAB       *altered_reloid_cache                      = NULL; // Set<Oid>
+static TimestampTz altered_reloid_cache_last_overflow_report = 0;
+
+static const char *altered_reloid_cache_warning =
+        "the number of altered reloid cache entries reached the limit, please increase "
+        "the GUC value for diskquota.max_active_tables.";
 
 /* active table hooks which detect the disk file size change. */
 static file_create_hook_type   prev_file_create_hook   = NULL;
@@ -236,7 +246,9 @@ report_altered_reloid(Oid reloid)
 	if (IsRoleMirror() || IS_QUERY_DISPATCHER()) return;
 
 	LWLockAcquire(diskquota_locks.altered_reloid_cache_lock, LW_EXCLUSIVE);
-	hash_search(altered_reloid_cache, &reloid, HASH_ENTER, NULL);
+	HASHACTION action = check_hash_fullness(altered_reloid_cache, diskquota_max_active_tables,
+	                                        altered_reloid_cache_warning, &altered_reloid_cache_last_overflow_report);
+	hash_search(altered_reloid_cache, &reloid, action, NULL);
 	LWLockRelease(diskquota_locks.altered_reloid_cache_lock);
 }
 
@@ -318,17 +330,11 @@ report_active_table_helper(const RelFileNodeBackend *relFileNode)
 	item.tablespaceoid = relFileNode->node.spcNode;
 
 	LWLockAcquire(diskquota_locks.active_table_lock, LW_EXCLUSIVE);
-	entry = hash_search(active_tables_map, &item, HASH_ENTER_NULL, &found);
+	HASHACTION action = check_hash_fullness(active_tables_map, diskquota_max_active_tables, active_tables_map_warning,
+	                                        &active_tables_map_last_overflow_report);
+	entry             = hash_search(active_tables_map, &item, action, &found);
 	if (entry && !found) *entry = item;
 
-	if (!found && entry == NULL)
-	{
-		/*
-		 * We may miss the file size change of this relation at current
-		 * refresh interval.
-		 */
-		ereport(WARNING, (errmsg("Share memory is not enough for active tables.")));
-	}
 	LWLockRelease(diskquota_locks.active_table_lock);
 }
 
@@ -856,8 +862,9 @@ get_active_tables_oid(void)
 	hash_seq_init(&iter, local_active_table_file_map);
 	while ((active_table_file_entry = (DiskQuotaActiveTableFileEntry *)hash_seq_search(&iter)) != NULL)
 	{
-		/* TODO: handle possible ERROR here so that the bgworker will not go down. */
-		hash_search(active_tables_map, active_table_file_entry, HASH_ENTER, NULL);
+		HASHACTION action = check_hash_fullness(active_tables_map, diskquota_max_active_tables,
+		                                        active_tables_map_warning, &active_tables_map_last_overflow_report);
+		hash_search(active_tables_map, active_table_file_entry, action, NULL);
 	}
 	/* TODO: hash_seq_term(&iter); */
 	LWLockRelease(diskquota_locks.active_table_lock);
@@ -919,7 +926,9 @@ get_active_tables_oid(void)
 		LWLockAcquire(diskquota_locks.active_table_lock, LW_EXCLUSIVE);
 		while ((active_table_file_entry = (DiskQuotaActiveTableFileEntry *)hash_seq_search(&iter)) != NULL)
 		{
-			entry = hash_search(active_tables_map, active_table_file_entry, HASH_ENTER_NULL, &found);
+			HASHACTION action = check_hash_fullness(active_tables_map, diskquota_max_active_tables,
+			                                        active_tables_map_warning, &active_tables_map_last_overflow_report);
+			entry             = hash_search(active_tables_map, active_table_file_entry, action, &found);
 			if (entry) *entry = *active_table_file_entry;
 		}
 		LWLockRelease(diskquota_locks.active_table_lock);

src/gp_activetable.h

@@ -42,9 +42,7 @@ extern void  init_active_table_hook(void);
 extern void  init_shm_worker_active_tables(void);
 extern void  init_lock_active_tables(void);
 
-extern HTAB *active_tables_map;
 extern HTAB *monitored_dbid_cache;
-extern HTAB *altered_reloid_cache;
 
 #ifndef atooid
 #define atooid(x) ((Oid)strtoul((x), NULL, 10))