Delete memory mode "map" and "save". (#16604)

* Delete memory modes "map" and "save".

* Remove unmaintained exporting tests

* Remove references of map/save modes in docs.

* Remove more references to map/save from docs.

26 files changed, 27 insertions, 4092 deletions

diff --git a/collectors/plugins.d/pluginsd_parser.c b/collectors/plugins.d/pluginsd_parser.c
index 1ec173b1d4..c7ecd2b765 100644
--- a/collectors/plugins.d/pluginsd_parser.c
+++ b/collectors/plugins.d/pluginsd_parser.c
@@ -856,7 +856,7 @@ static inline PARSER_RC pluginsd_begin_v2(char **words, size_t num_words, PARSER
     st->counter++;
     st->counter_done++;
 
-    // these are only needed for db mode RAM, SAVE, MAP, ALLOC
+    // these are only needed for db mode RAM, ALLOC
     st->db.current_entry++;
     if(st->db.current_entry >= st->db.entries)
         st->db.current_entry -= st->db.entries;
diff --git a/collectors/plugins.d/pluginsd_replication.c b/collectors/plugins.d/pluginsd_replication.c
index 8b58a286d4..8d09752109 100644
--- a/collectors/plugins.d/pluginsd_replication.c
+++ b/collectors/plugins.d/pluginsd_replication.c
@@ -71,7 +71,7 @@ PARSER_RC pluginsd_replay_begin(char **words, size_t num_words, PARSER *parser)
             st->counter++;
             st->counter_done++;
 
-            // these are only needed for db mode RAM, SAVE, MAP, ALLOC
+            // these are only needed for db mode RAM, ALLOC
             st->db.current_entry++;
             if(st->db.current_entry >= st->db.entries)
                 st->db.current_entry -= st->db.entries;
diff --git a/daemon/buildinfo.c b/daemon/buildinfo.c
index d7603393f4..a84620f53c 100644
--- a/daemon/buildinfo.c
+++ b/daemon/buildinfo.c
@@ -57,8 +57,6 @@ typedef enum __attribute__((packed)) {
     BIB_DB_DBENGINE,
     BIB_DB_ALLOC,
     BIB_DB_RAM,
-    BIB_DB_MAP,
-    BIB_DB_SAVE,
     BIB_DB_NONE,
     BIB_CONNECTIVITY_ACLK,
     BIB_CONNECTIVITY_HTTPD_STATIC,
@@ -554,22 +552,6 @@ static struct {
                 .json = "ram",
                 .value = NULL,
         },
-        [BIB_DB_MAP] = {
-                .category = BIC_DATABASE,
-                .type = BIT_BOOLEAN,
-                .analytics = NULL,
-                .print = "map",
-                .json = "map",
-                .value = NULL,
-        },
-        [BIB_DB_SAVE] = {
-                .category = BIC_DATABASE,
-                .type = BIT_BOOLEAN,
-                .analytics = NULL,
-                .print = "save",
-                .json = "save",
-                .value = NULL,
-        },
         [BIB_DB_NONE] = {
                 .category = BIC_DATABASE,
                 .type = BIT_BOOLEAN,
@@ -1101,8 +1083,6 @@ __attribute__((constructor)) void initialize_build_info(void) {
 #endif
     build_info_set_status(BIB_DB_ALLOC, true);
     build_info_set_status(BIB_DB_RAM, true);
-    build_info_set_status(BIB_DB_MAP, true);
-    build_info_set_status(BIB_DB_SAVE, true);
     build_info_set_status(BIB_DB_NONE, true);
 
     build_info_set_status(BIB_CONNECTIVITY_HTTPD_STATIC, true);
diff --git a/daemon/commands.c b/daemon/commands.c
index 75cccf7c4f..9cfc581c60 100644
--- a/daemon/commands.c
+++ b/daemon/commands.c
@@ -36,7 +36,6 @@ struct command_context {
 /* Forward declarations */
 static cmd_status_t cmd_help_execute(char *args, char **message);
 static cmd_status_t cmd_reload_health_execute(char *args, char **message);
-static cmd_status_t cmd_save_database_execute(char *args, char **message);
 static cmd_status_t cmd_reopen_logs_execute(char *args, char **message);
 static cmd_status_t cmd_exit_execute(char *args, char **message);
 static cmd_status_t cmd_fatal_execute(char *args, char **message);
@@ -52,7 +51,6 @@ static cmd_status_t cmd_dumpconfig(char *args, char **message);
 static command_info_t command_info_array[] = {
         {"help", cmd_help_execute, CMD_TYPE_HIGH_PRIORITY},                  // show help menu
         {"reload-health", cmd_reload_health_execute, CMD_TYPE_ORTHOGONAL},   // reload health configuration
-        {"save-database", cmd_save_database_execute, CMD_TYPE_ORTHOGONAL},   // save database for memory mode save
         {"reopen-logs", cmd_reopen_logs_execute, CMD_TYPE_ORTHOGONAL},       // Close and reopen log files
         {"shutdown-agent", cmd_exit_execute, CMD_TYPE_EXCLUSIVE},            // exit cleanly
         {"fatal-agent", cmd_fatal_execute, CMD_TYPE_HIGH_PRIORITY},          // exit with fatal error
@@ -150,20 +148,6 @@ static cmd_status_t cmd_reload_health_execute(char *args, char **message)
     return CMD_STATUS_SUCCESS;
 }
 
-static cmd_status_t cmd_save_database_execute(char *args, char **message)
-{
-    (void)args;
-    (void)message;
-
-    nd_log_limits_unlimited();
-    netdata_log_info("COMMAND: Saving databases.");
-    rrdhost_save_all();
-    netdata_log_info("COMMAND: Databases saved.");
-    nd_log_limits_reset();
-
-    return CMD_STATUS_SUCCESS;
-}
-
 static cmd_status_t cmd_reopen_logs_execute(char *args, char **message)
 {
     (void)args;
diff --git a/daemon/commands.h b/daemon/commands.h
index 368a70a0f4..45a76110ca 100644
--- a/daemon/commands.h
+++ b/daemon/commands.h
@@ -9,7 +9,6 @@
 typedef enum cmd {
     CMD_HELP = 0,
     CMD_RELOAD_HEALTH,
-    CMD_SAVE_DATABASE,
     CMD_REOPEN_LOGS,
     CMD_EXIT,
     CMD_FATAL,
diff --git a/daemon/config/README.md b/daemon/config/README.md
index 11ba2a1bc7..0642330f47 100644
--- a/daemon/config/README.md
+++ b/daemon/config/README.md
@@ -88,8 +88,8 @@ Please note that your data history will be lost if you have modified `history` p
 
 |                    setting                    |  default   | info                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
 |:---------------------------------------------:|:----------:|:---------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------|
-|                     mode                      | `dbengine` | `dbengine`: The default for long-term metrics storage with efficient RAM and disk usage. Can be extended with `dbengine page cache size MB` and `dbengine disk space MB`. <br />`save`: Netdata will save its round robin database on exit and load it on startup. <br />`map`: Cache files will be updated in real-time. Not ideal for systems with high load or slow disks (check `man mmap`). <br />`ram`: The round-robin database will be temporary and it will be lost when Netdata exits. <br />`alloc`: Similar to `ram`, but can significantly reduce memory usage, when combined with a low retention and does not support KSM. <br />`none`: Disables the database at this host, and disables health monitoring entirely, as that requires a database of metrics. Not to be used together with streaming. |
-|                   retention                   |   `3600`   | Used with `mode = save/map/ram/alloc`, not the default `mode = dbengine`. This number reflects the number of entries the `netdata` daemon will by default keep in memory for each chart dimension. Check [Memory Requirements](https://github.com/netdata/netdata/blob/master/database/README.md) for more information.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
+|                     mode                      | `dbengine` | `dbengine`: The default for long-term metrics storage with efficient RAM and disk usage. Can be extended with `dbengine page cache size MB` and `dbengine disk space MB`. <br />`ram`: The round-robin database will be temporary and it will be lost when Netdata exits. <br />`alloc`: Similar to `ram`, but can significantly reduce memory usage, when combined with a low retention and does not support KSM. <br />`none`: Disables the database at this host, and disables health monitoring entirely, as that requires a database of metrics. Not to be used together with streaming. |
+|                   retention                   |   `3600`   | Used with `mode = ram/alloc`, not the default `mode = dbengine`. This number reflects the number of entries the `netdata` daemon will by default keep in memory for each chart dimension. Check [Memory Requirements](https://github.com/netdata/netdata/blob/master/database/README.md) for more information.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                              |
 |                 storage tiers                 |    `1`     | The number of storage tiers you want to have in your dbengine. Check the tiering mechanism in the [dbengine's reference](https://github.com/netdata/netdata/blob/master/database/engine/README.md#tiering). You can have up to 5 tiers of data (including the _Tier 0_). This number ranges between 1 and 5.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                         |
 |          dbengine page cache size MB          |    `32`    | Determines the amount of RAM in MiB that is dedicated to caching for _Tier 0_ Netdata metric values.                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                 |
 |   dbengine tier **`N`** page cache size MB    |    `32`    | Determines the amount of RAM in MiB that is dedicated for caching Netdata metric values of the **`N`** tier. <br /> `N belongs to [1..4]`                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                                            |
diff --git a/daemon/main.c b/daemon/main.c
index 3a9e009491..a88fef5e1f 100644
--- a/daemon/main.c
+++ b/daemon/main.c
@@ -404,10 +404,6 @@ void netdata_cleanup_and_exit(int ret, const char *action, const char *action_re
 
     web_client_cache_destroy();
 
-    delta_shutdown_time("clean rrdhost database");
-
-    rrdhost_cleanup_all();
-
     delta_shutdown_time("stop aclk threads");
 
     timeout = !service_wait_exit(
@@ -1229,7 +1225,7 @@ static void get_netdata_configured_variables() {
 #else
     if (default_rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE) {
        error_report("RRD_MEMORY_MODE_DBENGINE is not supported in this platform. The agent will use db mode 'save' instead.");
-       default_rrd_memory_mode = RRD_MEMORY_MODE_SAVE;
+       default_rrd_memory_mode = RRD_MEMORY_MODE_RAM;
     }
 #endif
 
diff --git a/daemon/service.c b/daemon/service.c
index 3f47a8fa27..e87d8ed40b 100644
--- a/daemon/service.c
+++ b/daemon/service.c
@@ -16,11 +16,7 @@
 #define WORKER_JOB_CLEANUP_ORPHAN_HOSTS             6
 #define WORKER_JOB_CLEANUP_OBSOLETE_CHARTS_ON_HOSTS 7
 #define WORKER_JOB_FREE_HOST                        9
-#define WORKER_JOB_SAVE_HOST_CHARTS                 10
-#define WORKER_JOB_DELETE_HOST_CHARTS               11
 #define WORKER_JOB_FREE_CHART                       12
-#define WORKER_JOB_SAVE_CHART                       13
-#define WORKER_JOB_DELETE_CHART                     14
 #define WORKER_JOB_FREE_DIMENSION                   15
 #define WORKER_JOB_PGC_MAIN_EVICT                   16
 #define WORKER_JOB_PGC_MAIN_FLUSH                   17
@@ -38,13 +34,6 @@ static void svc_rrddim_obsolete_to_archive(RRDDIM *rd) {
     rrddim_flag_set(rd, RRDDIM_FLAG_ARCHIVED);
     rrddim_flag_clear(rd, RRDDIM_FLAG_OBSOLETE);
 
-    const char *cache_filename = rrddim_cache_filename(rd);
-    if(cache_filename) {
-        netdata_log_info("Deleting dimension file '%s'.", cache_filename);
-        if (unlikely(unlink(cache_filename) == -1))
-            netdata_log_error("Cannot delete dimension file '%s'", cache_filename);
-    }
-
     if (rd->rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE) {
         rrddimvar_delete_all(rd);
 
@@ -133,17 +122,6 @@ static void svc_rrdset_obsolete_to_free(RRDSET *st) {
     // has to be run after all dimensions are archived - or use-after-free will occur
     rrdvar_delete_all(st->rrdvars);
 
-    if(st->rrd_memory_mode != RRD_MEMORY_MODE_DBENGINE) {
-        if(rrdhost_option_check(st->rrdhost, RRDHOST_OPTION_DELETE_OBSOLETE_CHARTS)) {
-            worker_is_busy(WORKER_JOB_DELETE_CHART);
-            rrdset_delete_files(st);
-        }
-        else {
-            worker_is_busy(WORKER_JOB_SAVE_CHART);
-            rrdset_save(st);
-        }
-    }
-
     rrdset_free(st);
 }
 
@@ -269,28 +247,11 @@ restart_after_removal:
         if(!rrdhost_should_be_removed(host, protected_host, now))
             continue;
 
-        bool is_archived = rrdhost_flag_check(host, RRDHOST_FLAG_ARCHIVED);
-        if (!is_archived) {
-            netdata_log_info("Host '%s' with machine guid '%s' is obsolete - cleaning up.", rrdhost_hostname(host), host->machine_guid);
-
-            if (rrdhost_option_check(host, RRDHOST_OPTION_DELETE_ORPHAN_HOST)
-                /* don't delete multi-host DB host files */
-                && !(host->rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE && is_storage_engine_shared(host->db[0].si))
-            ) {
-                worker_is_busy(WORKER_JOB_DELETE_HOST_CHARTS);
-                rrdhost_delete_charts(host);
-            }
-            else {
-                worker_is_busy(WORKER_JOB_SAVE_HOST_CHARTS);
-                rrdhost_save_charts(host);
-            }
-        }
-
         bool force = false;
-
         if (rrdhost_option_check(host, RRDHOST_OPTION_EPHEMERAL_HOST) && now - host->last_connected > rrdhost_free_ephemeral_time_s)
             force = true;
 
+        bool is_archived = rrdhost_flag_check(host, RRDHOST_FLAG_ARCHIVED);
         if (!force && is_archived)
             continue;
 
@@ -339,11 +300,7 @@ void *service_main(void *ptr)
     worker_register_job_name(WORKER_JOB_CLEANUP_ORPHAN_HOSTS, "cleanup orphan hosts");
     worker_register_job_name(WORKER_JOB_CLEANUP_OBSOLETE_CHARTS_ON_HOSTS, "cleanup obsolete charts on all hosts");
     worker_register_job_name(WORKER_JOB_FREE_HOST, "free host");
-    worker_register_job_name(WORKER_JOB_SAVE_HOST_CHARTS, "save host charts");
-    worker_register_job_name(WORKER_JOB_DELETE_HOST_CHARTS, "delete host charts");
     worker_register_job_name(WORKER_JOB_FREE_CHART, "free chart");
-    worker_register_job_name(WORKER_JOB_SAVE_CHART, "save chart");
-    worker_register_job_name(WORKER_JOB_DELETE_CHART, "delete chart");
     worker_register_job_name(WORKER_JOB_FREE_DIMENSION, "free dimension");
     worker_register_job_name(WORKER_JOB_PGC_MAIN_EVICT, "main cache evictions");
     worker_register_job_name(WORKER_JOB_PGC_MAIN_FLUSH, "main cache flushes");
diff --git a/daemon/signals.c b/daemon/signals.c
index dcc09b892a..c014452b7d 100644
--- a/daemon/signals.c
+++ b/daemon/signals.c
@@ -6,7 +6,6 @@ typedef enum signal_action {
     NETDATA_SIGNAL_END_OF_LIST,
     NETDATA_SIGNAL_IGNORE,
     NETDATA_SIGNAL_EXIT_CLEANLY,
-    NETDATA_SIGNAL_SAVE_DATABASE,
     NETDATA_SIGNAL_REOPEN_LOGS,
     NETDATA_SIGNAL_RELOAD_HEALTH,
     NETDATA_SIGNAL_FATAL,
@@ -24,7 +23,6 @@ static struct {
         { SIGQUIT, "SIGQUIT", 0, NETDATA_SIGNAL_EXIT_CLEANLY  },
         { SIGTERM, "SIGTERM", 0, NETDATA_SIGNAL_EXIT_CLEANLY  },
         { SIGHUP,  "SIGHUP",  0, NETDATA_SIGNAL_REOPEN_LOGS   },
-        { SIGUSR1, "SIGUSR1", 0, NETDATA_SIGNAL_SAVE_DATABASE },
         { SIGUSR2, "SIGUSR2", 0, NETDATA_SIGNAL_RELOAD_HEALTH },
         { SIGBUS,  "SIGBUS",  0, NETDATA_SIGNAL_FATAL         },
         { SIGCHLD, "SIGCHLD", 0, NETDATA_SIGNAL_CHILD         },
@@ -209,13 +207,6 @@ void signals_handle(void) {
                                 execute_command(CMD_RELOAD_HEALTH, NULL, NULL);
                                 break;
 
-                            case NETDATA_SIGNAL_SAVE_DATABASE:
-                                nd_log_limits_unlimited();
-                                netdata_log_info("SIGNAL: Received %s. Saving databases...", name);
-                                nd_log_limits_reset();
-                                execute_command(CMD_SAVE_DATABASE, NULL, NULL);
-                                break;
-
                             case NETDATA_SIGNAL_REOPEN_LOGS:
                                 nd_log_limits_unlimited();
                                 netdata_log_info("SIGNAL: Received %s. Reopening all log files...", name);
diff --git a/daemon/unit_test.c b/daemon/unit_test.c
index 7407876723..4951d66c99 100644
--- a/daemon/unit_test.c
+++ b/daemon/unit_test.c
@@ -2238,7 +2238,6 @@ int test_dbengine(void)
 
     rrd_wrlock();
     rrdeng_prepare_exit((struct rrdengine_instance *)host->db[0].si);
-    rrdhost_delete_charts(host);
     rrdeng_exit((struct rrdengine_instance *)host->db[0].si);
     rrdeng_enq_cmd(NULL, RRDENG_OPCODE_SHUTDOWN_EVLOOP, NULL, NULL, STORAGE_PRIORITY_BEST_EFFORT, NULL, NULL);
     rrd_unlock();
@@ -2648,7 +2647,6 @@ void dbengine_stress_test(unsigned TEST_DURATION_SEC, unsigned DSET_CHARTS, unsi
     freez(query_threads);
     rrd_wrlock();
     rrdeng_prepare_exit((struct rrdengine_instance *)host->db[0].si);
-    rrdhost_delete_charts(host);
     rrdeng_exit((struct rrdengine_instance *)host->db[0].si);
     rrdeng_enq_cmd(NULL, RRDENG_OPCODE_SHUTDOWN_EVLOOP, NULL, NULL, STORAGE_PRIORITY_BEST_EFFORT, NULL, NULL);
     rrd_unlock();
diff --git a/database/README.md b/database/README.md
index c5750e1147..b0a8e176ce 100644
--- a/database/README.md
+++ b/database/README.md
@@ -12,19 +12,10 @@ Netdata is fully capable of long-term metrics storage, at per-second granularity
 
 2. `ram`, data are purely in memory. Data are never saved on disk. This mode uses `mmap()` and supports [KSM](#ksm).
 
-3. `save`, data are only in RAM while Netdata runs and are saved to / loaded from disk on Netdata restart. It also
-   uses `mmap()` and supports [KSM](#ksm).
-
-4. `map`, data are in memory mapped files. This works like the swap. When Netdata writes data on its memory, the Linux
-   kernel marks the related memory pages as dirty and automatically starts updating them on disk. Unfortunately we
-   cannot control how frequently this works. The Linux kernel uses exactly the same algorithm it uses for its swap
-   memory. This mode uses `mmap()` but does not support [KSM](#ksm). _Keep in mind though, this option will have a
-   constant write on your disk._
-
-5. `alloc`, like `ram` but it uses `calloc()` and does not support [KSM](#ksm). This mode is the fallback for all others
+3. `alloc`, like `ram` but it uses `calloc()` and does not support [KSM](#ksm). This mode is the fallback for all others
    except `none`.
 
-6. `none`, without a database (collected metrics can only be streamed to another Netdata).
+4. `none`, without a database (collected metrics can only be streamed to another Netdata).
 
 ## Which database mode to use
 
@@ -47,7 +38,7 @@ You can select the database mode by editing `netdata.conf` and setting:
 
 ```conf
 [db]
-  # dbengine (default), ram, save (the default if dbengine not available), map (swap like), none, alloc
+  # dbengine (default), ram (the default if dbengine not available), alloc, none
   mode = dbengine
 ```
 
diff --git a/database/rrd.c b/database/rrd.c
index 5b7752a5ea..b664ad3ae8 100644
--- a/database/rrd.c
+++ b/database/rrd.c
@@ -19,7 +19,7 @@ int default_rrd_history_entries = RRD_DEFAULT_HISTORY_ENTRIES;
 #ifdef ENABLE_DBENGINE
 RRD_MEMORY_MODE default_rrd_memory_mode = RRD_MEMORY_MODE_DBENGINE;
 #else
-RRD_MEMORY_MODE default_rrd_memory_mode = RRD_MEMORY_MODE_SAVE;
+RRD_MEMORY_MODE default_rrd_memory_mode = RRD_MEMORY_MODE_RAM;
 #endif
 int gap_when_lost_iterations_above = 1;
 
@@ -32,15 +32,9 @@ inline const char *rrd_memory_mode_name(RRD_MEMORY_MODE id) {
         case RRD_MEMORY_MODE_RAM:
             return RRD_MEMORY_MODE_RAM_NAME;
 
-        case RRD_MEMORY_MODE_MAP:
-            return RRD_MEMORY_MODE_MAP_NAME;
-
         case RRD_MEMORY_MODE_NONE:
             return RRD_MEMORY_MODE_NONE_NAME;
 
-        case RRD_MEMORY_MODE_SAVE:
-            return RRD_MEMORY_MODE_SAVE_NAME;
-
         case RRD_MEMORY_MODE_ALLOC:
             return RRD_MEMORY_MODE_ALLOC_NAME;
 
@@ -53,7 +47,7 @@ inline const char *rrd_memory_mode_name(RRD_MEMORY_MODE id) {
         return eng->name;
     }
 
-    return RRD_MEMORY_MODE_SAVE_NAME;
+    return RRD_MEMORY_MODE_RAM_NAME;
 }
 
 RRD_MEMORY_MODE rrd_memory_mode_id(const char *name) {
@@ -62,7 +56,7 @@ RRD_MEMORY_MODE rrd_memory_mode_id(const char *name) {
         return eng->id;
     }
 
-    return RRD_MEMORY_MODE_SAVE;
+    return RRD_MEMORY_MODE_RAM;
 }
 
 
@@ -133,28 +127,6 @@ const char *rrdset_type_name(RRDSET_TYPE chart_type) {
 }
 
 // ----------------------------------------------------------------------------
-// RRD - cache directory
-
-char *rrdhost_cache_dir_for_rrdset_alloc(RRDHOST *host, const char *id) {
-    char *ret = NULL;
-
-    char b[FILENAME_MAX + 1];
-    char n[FILENAME_MAX + 1];
-    rrdset_strncpyz_name(b, id, FILENAME_MAX);
-
-    snprintfz(n, FILENAME_MAX, "%s/%s", host->cache_dir, b);
-    ret = strdupz(n);
-
-    if(host->rrd_memory_mode == RRD_MEMORY_MODE_MAP || host->rrd_memory_mode == RRD_MEMORY_MODE_SAVE) {
-        int r = mkdir(ret, 0775);
-        if(r != 0 && errno != EEXIST)
-            netdata_log_error("Cannot create directory '%s'", ret);
-    }
-
-    return ret;
-}
-
-// ----------------------------------------------------------------------------
 // RRD - string management
 
 STRING *rrd_string_strdupz(const char *s) {
diff --git a/database/rrd.h b/database/rrd.h
index b63a7e8340..1a98e5eef2 100644
--- a/database/rrd.h
+++ b/database/rrd.h
@@ -79,8 +79,6 @@ struct pg_cache_page_index;
 typedef enum __attribute__ ((__packed__)) rrd_memory_mode {
     RRD_MEMORY_MODE_NONE     = 0,
     RRD_MEMORY_MODE_RAM      = 1,
-    RRD_MEMORY_MODE_MAP      = 2,
-    RRD_MEMORY_MODE_SAVE     = 3,
     RRD_MEMORY_MODE_ALLOC    = 4,
     RRD_MEMORY_MODE_DBENGINE = 5,
 
@@ -89,8 +87,6 @@ typedef enum __attribute__ ((__packed__)) rrd_memory_mode {
 
 #define RRD_MEMORY_MODE_NONE_NAME "none"
 #define RRD_MEMORY_MODE_RAM_NAME "ram"
-#define RRD_MEMORY_MODE_MAP_NAME "map"
-#define RRD_MEMORY_MODE_SAVE_NAME "save"
 #define RRD_MEMORY_MODE_ALLOC_NAME "alloc"
 #define RRD_MEMORY_MODE_DBENGINE_NAME "dbengine"
 
@@ -325,13 +321,12 @@ struct rrddim {
 #endif
 
     // ------------------------------------------------------------------------
-    // db mode RAM, SAVE, MAP, ALLOC, NONE specifics
+    // db mode RAM, ALLOC, NONE specifics
     // TODO - they should be managed by storage engine
     //        (RRDDIM_DB_STATE ptr to an undefined structure, and a call to clean this up during destruction)
 
     struct {
         size_t memsize;                             // the memory allocated for this dimension (without RRDDIM)
-        void *rd_on_file;                           // pointer to the header written on disk
         storage_number *data;                       // the array of values
     } db;
 
@@ -381,22 +376,6 @@ size_t rrddim_size(void);
 #define rrddim_set_updated(rd) (rd)->collector.options |= RRDDIM_OPTION_UPDATED
 #define rrddim_clear_updated(rd) (rd)->collector.options &= ~RRDDIM_OPTION_UPDATED
 
-// returns the RRDDIM cache filename, or NULL if it does not exist
-const char *rrddim_cache_filename(RRDDIM *rd);
-
-// updated the header with the latest RRDDIM value, for memory mode MAP and SAVE
-void rrddim_memory_file_update(RRDDIM *rd);
-
-// free the memory file structures for memory mode MAP and SAVE
-void rrddim_memory_file_free(RRDDIM *rd);
-
-bool rrddim_memory_load_or_create_map_save(RRDSET *st, RRDDIM *rd, RRD_MEMORY_MODE memory_mode);
-
-// return the v019 header size of RRDDIM files
-size_t rrddim_memory_file_header_size(void);
-
-void rrddim_memory_file_save(RRDDIM *rd);
-
 // ------------------------------------------------------------------------
 // DATA COLLECTION STORAGE OPS
 
@@ -960,12 +939,6 @@ STRING *rrd_string_strdupz(const char *s);
 #define rrdset_number_of_dimensions(st) \
     dictionary_entries((st)->rrddim_root_index)
 
-void rrdset_memory_file_save(RRDSET *st);
-void rrdset_memory_file_free(RRDSET *st);
-void rrdset_memory_file_update(RRDSET *st);
-const char *rrdset_cache_filename(RRDSET *st);
-bool rrdset_memory_load_or_create_map_save(RRDSET *st_on_file, RRD_MEMORY_MODE memory_mode);
-
 #include "rrdcollector.h"
 #include "rrdfunctions.h"
 
@@ -1488,13 +1461,9 @@ RRDSET *rrdset_create_custom(RRDHOST *host
     rrdset_create(localhost, type, id, name, family, context, title, units, plugin, module, priority, update_every, chart_type)
 
 void rrdhost_free_all(void);
-void rrdhost_save_all(void);
-void rrdhost_cleanup_all(void);
 
 void rrdhost_system_info_free(struct rrdhost_system_info *system_info);
 void rrdhost_free___while_having_rrd_wrlock(RRDHOST *host, bool force);
-void rrdhost_save_charts(RRDHOST *host);
-void rrdhost_delete_charts(RRDHOST *host);
 
 int rrdhost_should_be_removed(RRDHOST *host, RRDHOST *protected_host, time_t now_s);
 
@@ -1623,8 +1592,6 @@ void rrdhost_set_is_parent_label(void);
 // ----------------------------------------------------------------------------
 // RRD internal functions
 
-void rrdset_delete_files(RRDSET *st);
-void rrdset_save(RRDSET *st);
 void rrdset_free(RRDSET *st);
 
 void rrddim_free(RRDSET *st, RRDDIM *rd);
@@ -1632,10 +1599,8 @@ void rrddim_free(RRDSET *st, RRDDIM *rd);
 #ifdef NETDATA_RRD_INTERNALS
 
 char *rrdhost_cache_dir_for_rrdset_alloc(RRDHOST *host, const char *id);
-const char *rrdset_cache_dir(RRDSET *st);
 
 void rrdset_reset(RRDSET *st);
-void rrdset_delete_obsolete_dimensions(RRDSET *st);
 
 #endif /* NETDATA_RRD_INTERNALS */
 
diff --git a/database/rrddim.c b/database/rrddim.c
index fe1bbc8546..2f56815a94 100644
--- a/database/rrddim.c
+++ b/database/rrddim.c
@@ -58,13 +58,6 @@ static void rrddim_insert_callback(const DICTIONARY_ITEM *item __maybe_unused, v
     if(rrdset_flag_check(st, RRDSET_FLAG_STORE_FIRST))
         rd->collector.counter = 1;
 
-    if(ctr->memory_mode == RRD_MEMORY_MODE_MAP || ctr->memory_mode == RRD_MEMORY_MODE_SAVE) {
-        if(!rrddim_memory_load_or_create_map_save(st, rd, ctr->memory_mode)) {
-            netdata_log_info("Failed to use memory mode %s for chart '%s', dimension '%s', falling back to ram", (ctr->memory_mode == RRD_MEMORY_MODE_MAP)?"map":"save", rrdset_name(st), rrddim_name(rd));
-            ctr->memory_mode = RRD_MEMORY_MODE_RAM;
-        }
-    }
-
     if(ctr->memory_mode == RRD_MEMORY_MODE_RAM) {
         size_t entries = st->db.entries;
         if(!entries) entries = 5;
@@ -212,15 +205,6 @@ static void rrddim_delete_callback(const DICTIONARY_ITEM *item __maybe_unused, v
 
     rrddimvar_delete_all(rd);
 
-    // free(rd->annotations);
-    //#ifdef ENABLE_ACLK
-    //    if (!netdata_exit)
-    //        aclk_send_dimension_update(rd);
-    //#endif
-
-    // this will free MEMORY_MODE_SAVE and MEMORY_MODE_MAP structures
-    rrddim_memory_file_free(rd);
-
     for(size_t tier = 0; tier < storage_tiers ;tier++) {
         if(!rd->tiers[tier].smh) continue;
 
@@ -589,180 +573,3 @@ collected_number rrddim_set(RRDSET *st, const char *id, collected_number value)
 
     return rrddim_set_by_pointer(st, rd, value);
 }
-
-
-// ----------------------------------------------------------------------------
-// compatibility layer for RRDDIM files v019
-
-#define RRDDIMENSION_MAGIC_V019  "NETDATA RRD DIMENSION FILE V019"
-
-struct avl_element_v019 {
-    void *avl_link[2];
-    signed char avl_balance;
-};
-
-struct rrddim_map_save_v019 {
-    struct avl_element_v019 avl;                    // ignored
-    void *id;                                       // ignored
-    void *name;                                     // ignored
-    uint32_t algorithm;                             // print warning on mismatch - update on load
-    uint32_t rrd_memory_mode;                       // ignored
-    long long multiplier;                           // print warning on mismatch - update on load
-    long long divisor;