Merging upstream version 1.30.0.

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

18 files changed, 629 insertions, 150 deletions

diff --git a/database/engine/pagecache.c b/database/engine/pagecache.c
index a18207100..d7698de01 100644
--- a/database/engine/pagecache.c
+++ b/database/engine/pagecache.c
@@ -699,6 +699,74 @@ void pg_cache_get_filtered_info_prev(struct rrdengine_instance *ctx, struct pg_c
     }
     uv_rwlock_rdunlock(&page_index->lock);
 }
+
+/**
+ * Searches for an unallocated page without triggering disk I/O. Attempts to reserve the page and get a reference.
+ * @param ctx DB context
+ * @param id lookup by UUID
+ * @param start_time exact starting time in usec
+ * @param ret_page_indexp Sets the page index pointer (*ret_page_indexp) for the given UUID.
+ * @return the page descriptor or NULL on failure. It can fail if:
+ *         1. The page is already allocated to the page cache.
+ *         2. It did not succeed to get a reference.
+ *         3. It did not succeed to reserve a spot in the page cache.
+ */
+struct rrdeng_page_descr *pg_cache_lookup_unpopulated_and_lock(struct rrdengine_instance *ctx, uuid_t *id,
+                                                               usec_t start_time)
+{
+    struct page_cache *pg_cache = &ctx->pg_cache;
+    struct rrdeng_page_descr *descr = NULL;
+    struct page_cache_descr *pg_cache_descr = NULL;
+    unsigned long flags;
+    Pvoid_t *PValue;
+    struct pg_cache_page_index *page_index = NULL;
+    Word_t Index;
+
+    uv_rwlock_rdlock(&pg_cache->metrics_index.lock);
+    PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, id, sizeof(uuid_t));
+    if (likely(NULL != PValue)) {
+        page_index = *PValue;
+    }
+    uv_rwlock_rdunlock(&pg_cache->metrics_index.lock);
+
+    if ((NULL == PValue) || !pg_cache_try_reserve_pages(ctx, 1)) {
+        /* Failed to find page or failed to reserve a spot in the cache */
+        return NULL;
+    }
+
+    uv_rwlock_rdlock(&page_index->lock);
+    Index = (Word_t)(start_time / USEC_PER_SEC);
+    PValue = JudyLGet(page_index->JudyL_array, Index, PJE0);
+    if (likely(NULL != PValue)) {
+        descr = *PValue;
+    }
+    if (NULL == PValue || 0 == descr->page_length) {
+        /* Failed to find non-empty page */
+        uv_rwlock_rdunlock(&page_index->lock);
+
+        pg_cache_release_pages(ctx, 1);
+        return NULL;
+    }
+
+    rrdeng_page_descr_mutex_lock(ctx, descr);
+    pg_cache_descr = descr->pg_cache_descr;
+    flags = pg_cache_descr->flags;
+    uv_rwlock_rdunlock(&page_index->lock);
+
+    if ((flags & RRD_PAGE_POPULATED) || !pg_cache_try_get_unsafe(descr, 1)) {
+        /* Failed to get reference or page is already populated */
+        rrdeng_page_descr_mutex_unlock(ctx, descr);
+
+        pg_cache_release_pages(ctx, 1);
+        return NULL;
+    }
+    /* success */
+    rrdeng_page_descr_mutex_unlock(ctx, descr);
+    rrd_stat_atomic_add(&ctx->stats.pg_cache_misses, 1);
+
+    return descr;
+}
+
 /**
  * Searches for pages in a time range and triggers disk I/O if necessary and possible.
  * Does not get a reference.
diff --git a/database/engine/pagecache.h b/database/engine/pagecache.h
index 31e9739da..d5350ef56 100644
--- a/database/engine/pagecache.h
+++ b/database/engine/pagecache.h
@@ -172,6 +172,8 @@ extern usec_t pg_cache_oldest_time_in_range(struct rrdengine_instance *ctx, uuid
 extern void pg_cache_get_filtered_info_prev(struct rrdengine_instance *ctx, struct pg_cache_page_index *page_index,
                                             usec_t point_in_time, pg_cache_page_info_filter_t *filter,
                                             struct rrdeng_page_info *page_info);
+extern struct rrdeng_page_descr *pg_cache_lookup_unpopulated_and_lock(struct rrdengine_instance *ctx, uuid_t *id,
+                                                                      usec_t start_time);
 extern unsigned
         pg_cache_preload(struct rrdengine_instance *ctx, uuid_t *id, usec_t start_time, usec_t end_time,
                          struct rrdeng_page_info **page_info_arrayp, struct pg_cache_page_index **ret_page_indexp);
diff --git a/database/engine/rrdengine.c b/database/engine/rrdengine.c
index 43135ff01..0c4a401cb 100644
--- a/database/engine/rrdengine.c
+++ b/database/engine/rrdengine.c
@@ -9,6 +9,8 @@ rrdeng_stats_t rrdeng_reserved_file_descriptors = 0;
 rrdeng_stats_t global_pg_cache_over_half_dirty_events = 0;
 rrdeng_stats_t global_flushing_pressure_page_deletions = 0;
 
+static unsigned pages_per_extent = MAX_PAGES_PER_EXTENT;
+
 static void sanity_check(void)
 {
     /* Magic numbers must fit in the super-blocks */
@@ -305,19 +307,32 @@ after_crc_check:
         }
     }
 
-    for (i = 0 ; i < xt_io_descr->descr_count; ++i) {
-        page = mallocz(RRDENG_BLOCK_SIZE);
-        descr = xt_io_descr->descr_array[i];
-        for (j = 0, page_offset = 0; j < count; ++j) {
+    for (i = 0, page_offset = 0; i < count; page_offset += header->descr[i++].page_length) {
+        uint8_t is_prefetched_page;
+        descr = NULL;
+        for (j = 0 ; j < xt_io_descr->descr_count; ++j) {
+            struct rrdeng_page_descr *descrj;
+
+            descrj = xt_io_descr->descr_array[j];
             /* care, we don't hold the descriptor mutex */
-            if (!uuid_compare(*(uuid_t *) header->descr[j].uuid, *descr->id) &&
-                header->descr[j].page_length == descr->page_length &&
-                header->descr[j].start_time == descr->start_time &&
-                header->descr[j].end_time == descr->end_time) {
+            if (!uuid_compare(*(uuid_t *) header->descr[i].uuid, *descrj->id) &&
+                header->descr[i].page_length == descrj->page_length &&
+                header->descr[i].start_time == descrj->start_time &&
+                header->descr[i].end_time == descrj->end_time) {
+                descr = descrj;
                 break;
             }
-            page_offset += header->descr[j].page_length;
         }
+        is_prefetched_page = 0;
+        if (!descr) { /* This extent page has not been requested. Try populating it for locality (best effort). */
+            descr = pg_cache_lookup_unpopulated_and_lock(ctx, (uuid_t *)header->descr[i].uuid,
+                                                         header->descr[i].start_time);
+            if (!descr)
+                continue; /* Failed to reserve a suitable page */
+            is_prefetched_page = 1;
+        }
+        page = mallocz(RRDENG_BLOCK_SIZE);
+
         /* care, we don't hold the descriptor mutex */
         if (have_read_error) {
             /* Applications should make sure NULL values match 0 as does SN_EMPTY_SLOT */
@@ -334,7 +349,7 @@ after_crc_check:
         pg_cache_descr->flags &= ~RRD_PAGE_READ_PENDING;
         rrdeng_page_descr_mutex_unlock(ctx, descr);
         pg_cache_replaceQ_insert(ctx, descr);
-        if (xt_io_descr->release_descr) {
+        if (xt_io_descr->release_descr || is_prefetched_page) {
             pg_cache_put(ctx, descr);
         } else {
             debug(D_RRDENGINE, "%s: Waking up waiters.", __func__);
@@ -666,7 +681,7 @@ static int do_flush_pages(struct rrdengine_worker_config* wc, int force, struct
          PValue = JudyLFirst(pg_cache->committed_page_index.JudyL_array, &Index, PJE0),
          descr = unlikely(NULL == PValue) ? NULL : *PValue ;
 
-         descr != NULL && count != MAX_PAGES_PER_EXTENT ;
+         descr != NULL && count != pages_per_extent ;
 
          PValue = JudyLNext(pg_cache->committed_page_index.JudyL_array, &Index, PJE0),
          descr = unlikely(NULL == PValue) ? NULL : *PValue) {
@@ -1031,6 +1046,21 @@ struct rrdeng_cmd rrdeng_deq_cmd(struct rrdengine_worker_config* wc)
     return ret;
 }
 
+static void load_configuration_dynamic(void)
+{
+    unsigned read_num;
+    static int printed_error = 0;
+
+    read_num = (unsigned) config_get_number(CONFIG_SECTION_GLOBAL, "dbengine extent pages",
+                                                    MAX_PAGES_PER_EXTENT);
+    if (read_num > 0 && read_num <= MAX_PAGES_PER_EXTENT) {
+        pages_per_extent = read_num;
+    } else if (!printed_error) {
+        printed_error = 1;
+        error("Invalid dbengine extent pages %u given. Defaulting to %u.", read_num, pages_per_extent);
+    }
+}
+
 void async_cb(uv_async_t *handle)
 {
     uv_stop(handle->loop);
@@ -1084,6 +1114,7 @@ void timer_cb(uv_timer_t* handle)
             }
         }
     }
+    load_configuration_dynamic();
 #ifdef NETDATA_INTERNAL_CHECKS
     {
         char buf[4096];
diff --git a/database/engine/rrdengine.h b/database/engine/rrdengine.h
index 87af04bff..2d48665f8 100644
--- a/database/engine/rrdengine.h
+++ b/database/engine/rrdengine.h
@@ -56,16 +56,20 @@ enum rrdeng_opcode {
     RRDENG_MAX_OPCODE
 };
 
+struct rrdeng_read_page {
+    struct rrdeng_page_descr *page_cache_descr;
+};
+
+struct rrdeng_read_extent {
+    struct rrdeng_page_descr *page_cache_descr[MAX_PAGES_PER_EXTENT];
+    int page_count;
+};
+
 struct rrdeng_cmd {
     enum rrdeng_opcode opcode;
     union {
-        struct rrdeng_read_page {
-            struct rrdeng_page_descr *page_cache_descr;
-        } read_page;
-        struct rrdeng_read_extent {
-            struct rrdeng_page_descr *page_cache_descr[MAX_PAGES_PER_EXTENT];
-            int page_count;
-        } read_extent;
+        struct rrdeng_read_page read_page;
+        struct rrdeng_read_extent read_extent;
         struct completion *completion;
     };
 };
@@ -230,4 +234,4 @@ extern void rrdeng_worker(void* arg);
 extern void rrdeng_enq_cmd(struct rrdengine_worker_config* wc, struct rrdeng_cmd *cmd);
 extern struct rrdeng_cmd rrdeng_deq_cmd(struct rrdengine_worker_config* wc);
 
-#endif /* NETDATA_RRDENGINE_H */
\ No newline at end of file
+#endif /* NETDATA_RRDENGINE_H */
diff --git a/database/engine/rrdengineapi.c b/database/engine/rrdengineapi.c
index 7b2ff5b72..cb46e06e3 100755
--- a/database/engine/rrdengineapi.c
+++ b/database/engine/rrdengineapi.c
@@ -691,6 +691,36 @@ time_t rrdeng_metric_oldest_time(RRDDIM *rd)
     return page_index->oldest_time / USEC_PER_SEC;
 }
 
+int rrdeng_metric_latest_time_by_uuid(uuid_t *dim_uuid, time_t *first_entry_t, time_t *last_entry_t)
+{
+    struct page_cache *pg_cache;
+    struct rrdengine_instance *ctx;
+    Pvoid_t *PValue;
+    struct pg_cache_page_index *page_index = NULL;
+
+    ctx = get_rrdeng_ctx_from_host(localhost);
+    if (unlikely(!ctx)) {
+        error("Failed to fetch multidb context");
+        return 1;
+    }
+    pg_cache = &ctx->pg_cache;
+
+    uv_rwlock_rdlock(&pg_cache->metrics_index.lock);
+    PValue = JudyHSGet(pg_cache->metrics_index.JudyHS_array, dim_uuid, sizeof(uuid_t));
+    if (likely(NULL != PValue)) {
+        page_index = *PValue;
+    }
+    uv_rwlock_rdunlock(&pg_cache->metrics_index.lock);
+
+    if (likely(page_index)) {
+        *first_entry_t = page_index->oldest_time / USEC_PER_SEC;
+        *last_entry_t = page_index->latest_time / USEC_PER_SEC;
+        return 0;
+    }
+
+    return 1;
+}
+
 /* Also gets a reference for the page */
 void *rrdeng_create_page(struct rrdengine_instance *ctx, uuid_t *id, struct rrdeng_page_descr **ret_descr)
 {
diff --git a/database/engine/rrdengineapi.h b/database/engine/rrdengineapi.h
index 41375b980..00e55e662 100644
--- a/database/engine/rrdengineapi.h
+++ b/database/engine/rrdengineapi.h
@@ -59,5 +59,6 @@ extern int rrdeng_init(RRDHOST *host, struct rrdengine_instance **ctxp, char *db
 
 extern int rrdeng_exit(struct rrdengine_instance *ctx);
 extern void rrdeng_prepare_exit(struct rrdengine_instance *ctx);
+extern int rrdeng_metric_latest_time_by_uuid(uuid_t *dim_uuid, time_t *first_entry_t, time_t *last_entry_t);
 
 #endif /* NETDATA_RRDENGINEAPI_H */
diff --git a/database/rrd.h b/database/rrd.h
index b16fcdc16..59d0501bd 100644
--- a/database/rrd.h
+++ b/database/rrd.h
@@ -34,12 +34,24 @@ struct pg_cache_page_index;
 #include "rrdcalc.h"
 #include "rrdcalctemplate.h"
 #include "../streaming/rrdpush.h"
+
+#ifndef ACLK_NG
 #include "../aclk/legacy/aclk_rrdhost_state.h"
+#else
+#include "aclk/aclk.h"
+#endif
+
+enum {
+    CONTEXT_FLAGS_ARCHIVE = 0x01,
+    CONTEXT_FLAGS_CHART   = 0x02,
+    CONTEXT_FLAGS_CONTEXT = 0x04
+};
 
 struct context_param {
     RRDDIM *rd;
     time_t first_entry_t;
     time_t last_entry_t;
+    uint8_t flags;
 };
 
 #define META_CHART_UPDATED 1
@@ -130,7 +142,7 @@ extern const char *rrd_algorithm_name(RRD_ALGORITHM algorithm);
 // RRD FAMILY
 
 struct rrdfamily {
-    avl avl;
+    avl_t avl;
 
     const char *family;
     uint32_t hash_family;
@@ -235,7 +247,7 @@ struct rrddim {
     // ------------------------------------------------------------------------
     // binary indexing structures
 
-    avl avl;                                        // the binary index - this has to be first member!
+    avl_t avl;                                      // the binary index - this has to be first member!
 
     // ------------------------------------------------------------------------
     // the dimension definition
@@ -336,6 +348,18 @@ union rrddim_collect_handle {
 
 // ----------------------------------------------------------------------------
 // iterator state for RRD dimension data queries
+
+#ifdef ENABLE_DBENGINE
+struct rrdeng_query_handle {
+    struct rrdeng_page_descr *descr;
+    struct rrdengine_instance *ctx;
+    struct pg_cache_page_index *page_index;
+    time_t next_page_time;
+    time_t now;
+    unsigned position;
+};
+#endif
+
 struct rrddim_query_handle {
     RRDDIM *rd;
     time_t start_time;
@@ -347,14 +371,7 @@ struct rrddim_query_handle {
             uint8_t finished;
         } slotted;                         // state the legacy code uses
 #ifdef ENABLE_DBENGINE
-        struct rrdeng_query_handle {
-            struct rrdeng_page_descr *descr;
-            struct rrdengine_instance *ctx;
-            struct pg_cache_page_index *page_index;
-            time_t next_page_time;
-            time_t now;
-            unsigned position;
-        } rrdeng; // state the database engine uses
+        struct rrdeng_query_handle rrdeng; // state the database engine uses
 #endif
     };
 };
@@ -365,9 +382,9 @@ struct rrddim_query_handle {
 struct rrddim_volatile {
 #ifdef ENABLE_DBENGINE
     uuid_t *rrdeng_uuid;                 // database engine metric UUID
-    uuid_t *metric_uuid;                 // global UUID for this metric (unique_across hosts)
     struct pg_cache_page_index *page_index;
 #endif
+    uuid_t *metric_uuid;                 // global UUID for this metric (unique_across hosts)
     union rrddim_collect_handle handle;
     // ------------------------------------------------------------------------
     // function pointers that handle data collection
@@ -469,8 +486,8 @@ struct rrdset {
     // ------------------------------------------------------------------------
     // binary indexing structures
 
-    avl avl;                                        // the index, with key the id - this has to be first!
-    avl avlname;                                    // the index, with key the name
+    avl_t avl;                                      // the index, with key the id - this has to be first!
+    avl_t avlname;                                  // the index, with key the name
 
     // ------------------------------------------------------------------------
     // the set configuration
@@ -523,7 +540,10 @@ struct rrdset {
     size_t counter;                                 // the number of times we added values to this database
     size_t counter_done;                            // the number of times rrdset_done() has been called
 
-    time_t last_accessed_time;                      // the last time this RRDSET has been accessed
+    union {
+        time_t last_accessed_time;                  // the last time this RRDSET has been accessed
+        time_t last_entry_t;                        // the last_entry_t computed for transient RRDSET
+    };
     time_t upstream_resync_time;                    // the timestamp up to which we should resync clock upstream
 
     char *plugin_name;                              // the name of the plugin that generated this
@@ -722,7 +742,7 @@ struct rrdhost_system_info {
 };
 
 struct rrdhost {
-    avl avl;                                        // the index of hosts
+    avl_t avl;                                      // the index of hosts
 
     // ------------------------------------------------------------------------
     // host information
@@ -851,8 +871,8 @@ struct rrdhost {
 
 #ifdef ENABLE_DBENGINE
     struct rrdengine_instance *rrdeng_ctx;          // DB engine instance for this host
-    uuid_t  host_uuid;                              // Global GUID for this host
 #endif
+    uuid_t  host_uuid;                              // Global GUID for this host
 
 #ifdef ENABLE_HTTPS
     struct netdata_ssl ssl;                         //Structure used to encrypt the connection
@@ -999,13 +1019,13 @@ extern void rrdhost_free_all(void);
 extern void rrdhost_save_all(void);
 extern void rrdhost_cleanup_all(void);
 
-extern void rrdhost_cleanup_orphan_hosts_nolock(RRDHOST *protected);
+extern void rrdhost_cleanup_orphan_hosts_nolock(RRDHOST *protected_host);
 extern void rrdhost_system_info_free(struct rrdhost_system_info *system_info);
 extern void rrdhost_free(RRDHOST *host);
 extern void rrdhost_save_charts(RRDHOST *host);
 extern void rrdhost_delete_charts(RRDHOST *host);
 
-extern int rrdhost_should_be_removed(RRDHOST *host, RRDHOST *protected, time_t now);
+extern int rrdhost_should_be_removed(RRDHOST *host, RRDHOST *protected_host, time_t now);
 
 extern void rrdset_update_heterogeneous_flag(RRDSET *st);
 
@@ -1053,7 +1073,7 @@ extern void rrdset_isnot_obsolete(RRDSET *st);
 
 // checks if the RRDSET should be offered to viewers
 #define rrdset_is_available_for_viewers(st) (rrdset_flag_check(st, RRDSET_FLAG_ENABLED) && !rrdset_flag_check(st, RRDSET_FLAG_HIDDEN) && !rrdset_flag_check(st, RRDSET_FLAG_OBSOLETE) && !rrdset_flag_check(st, RRDSET_FLAG_ARCHIVED) && (st)->dimensions && (st)->rrd_memory_mode != RRD_MEMORY_MODE_NONE)
-#define rrdset_is_available_for_backends(st) (rrdset_flag_check(st, RRDSET_FLAG_ENABLED) && !rrdset_flag_check(st, RRDSET_FLAG_OBSOLETE) && !rrdset_flag_check(st, RRDSET_FLAG_ARCHIVED) && (st)->dimensions)
+#define rrdset_is_available_for_exporting_and_alarms(st) (rrdset_flag_check(st, RRDSET_FLAG_ENABLED) && !rrdset_flag_check(st, RRDSET_FLAG_OBSOLETE) && !rrdset_flag_check(st, RRDSET_FLAG_ARCHIVED) && (st)->dimensions)
 #define rrdset_is_archived(st) (rrdset_flag_check(st, RRDSET_FLAG_ARCHIVED) && (st)->dimensions)
 
 // get the total duration in seconds of the round robin database
@@ -1281,8 +1301,8 @@ extern int rrdfamily_compare(void *a, void *b);
 extern RRDFAMILY *rrdfamily_create(RRDHOST *host, const char *id);
 extern void rrdfamily_free(RRDHOST *host, RRDFAMILY *rc);
 
-#define rrdset_index_add(host, st) (RRDSET *)avl_insert_lock(&((host)->rrdset_root_index), (avl *)(st))
-#define rrdset_index_del(host, st) (RRDSET *)avl_remove_lock(&((host)->rrdset_root_index), (avl *)(st))
+#define rrdset_index_add(host, st) (RRDSET *)avl_insert_lock(&((host)->rrdset_root_index), (avl_t *)(st))
+#define rrdset_index_del(host, st) (RRDSET *)avl_remove_lock(&((host)->rrdset_root_index), (avl_t *)(st))
 extern RRDSET *rrdset_index_del_name(RRDHOST *host, RRDSET *st);
 
 extern void rrdset_free(RRDSET *st);
@@ -1312,7 +1332,7 @@ extern void set_host_properties(
 
 #ifdef ENABLE_DBENGINE
 #include "database/engine/rrdengineapi.h"
-#include "sqlite/sqlite_functions.h"
 #endif
+#include "sqlite/sqlite_functions.h"
 
 #endif /* NETDATA_RRD_H */
diff --git a/database/rrdcalc.c b/database/rrdcalc.c
index 935ee9c05..bc91da64f 100644
--- a/database/rrdcalc.c
+++ b/database/rrdcalc.c
@@ -472,7 +472,7 @@ inline RRDCALC *rrdcalc_create_from_template(RRDHOST *host, RRDCALCTEMPLATE *rt,
 
     rrdcalc_add_to_host(host, rc);
     if(!rt->foreachdim) {
-        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_health_log,(avl *)rc);
+        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_health_log,(avl_t *)rc);
         if (rdcmp != rc) {
             error("Cannot insert the alarm index ID %s",rc->name);
         }
@@ -605,17 +605,17 @@ void rrdcalc_unlink_and_free(RRDHOST *host, RRDCALC *rc) {
             error("Cannot unlink alarm '%s.%s' from host '%s': not found", rc->chart?rc->chart:"NOCHART", rc->name, host->hostname);
     }
 
-    RRDCALC *rdcmp = (RRDCALC *) avl_search_lock(&(host)->alarms_idx_health_log, (avl *)rc);
+    RRDCALC *rdcmp = (RRDCALC *) avl_search_lock(&(host)->alarms_idx_health_log, (avl_t *)rc);
     if (rdcmp) {
-        rdcmp = (RRDCALC *) avl_remove_lock(&(host)->alarms_idx_health_log, (avl *)rc);
+        rdcmp = (RRDCALC *) avl_remove_lock(&(host)->alarms_idx_health_log, (avl_t *)rc);
         if (!rdcmp) {
             error("Cannot remove the health alarm index from health_log");
         }
     }
 
-    rdcmp = (RRDCALC *) avl_search_lock(&(host)->alarms_idx_name, (avl *)rc);
+    rdcmp = (RRDCALC *) avl_search_lock(&(host)->alarms_idx_name, (avl_t *)rc);
     if (rdcmp) {
-        rdcmp = (RRDCALC *) avl_remove_lock(&(host)->alarms_idx_name, (avl *)rc);
+        rdcmp = (RRDCALC *) avl_remove_lock(&(host)->alarms_idx_name, (avl_t *)rc);
         if (!rdcmp) {
             error("Cannot remove the health alarm index from idx_name");
         }
@@ -727,7 +727,7 @@ void rrdcalc_labels_unlink() {
 int alarm_isrepeating(RRDHOST *host, uint32_t alarm_id) {
     RRDCALC findme;
     findme.id = alarm_id;
-    RRDCALC *rc = (RRDCALC *)avl_search_lock(&host->alarms_idx_health_log, (avl *)&findme);
+    RRDCALC *rc = (RRDCALC *)avl_search_lock(&host->alarms_idx_health_log, (avl_t *)&findme);
     if (!rc) {
         return 0;
     }
@@ -761,7 +761,7 @@ RRDCALC *alarm_max_last_repeat(RRDHOST *host, char *alarm_name,uint32_t hash) {
     RRDCALC findme;
     findme.name = alarm_name;
     findme.hash = hash;
-    RRDCALC *rc = (RRDCALC *)avl_search_lock(&host->alarms_idx_name, (avl *)&findme);
+    RRDCALC *rc = (RRDCALC *)avl_search_lock(&host->alarms_idx_name, (avl_t *)&findme);
 
     return rc;
 }
diff --git a/database/rrdcalc.h b/database/rrdcalc.h
index cd0d70049..27ff99a89 100644
--- a/database/rrdcalc.h
+++ b/database/rrdcalc.h
@@ -32,7 +32,7 @@
 
 
 struct rrdcalc {
-    avl avl;                        // the index, with key the id - this has to be first!
+    avl_t avl;                      // the index, with key the id - this has to be first!
     uint32_t id;                    // the unique id of this alarm
     uint32_t next_event_id;         // the next event id that will be used for this alarm
 
diff --git a/database/rrddim.c b/database/rrddim.c
index 6a1408595..b4ea34d2d 100644
--- a/database/rrddim.c
+++ b/database/rrddim.c
@@ -38,15 +38,15 @@ int rrddim_compare(void* a, void* b) {
     else return strcmp(((RRDDIM *)a)->id, ((RRDDIM *)b)->id);
 }
 
-#define rrddim_index_add(st, rd) (RRDDIM *)avl_insert_lock(&((st)->dimensions_index), (avl *)(rd))
-#define rrddim_index_del(st,rd ) (RRDDIM *)avl_remove_lock(&((st)->dimensions_index), (avl *)(rd))
+#define rrddim_index_add(st, rd) (RRDDIM *)avl_insert_lock(&((st)->dimensions_index), (avl_t *)(rd))
+#define rrddim_index_del(st,rd ) (RRDDIM *)avl_remove_lock(&((st)->dimensions_index), (avl_t *)(rd))
 
 static inline RRDDIM *rrddim_index_find(RRDSET *st, const char *id, uint32_t hash) {
     RRDDIM tmp = {
             .id = id,
             .hash = (hash)?hash:simple_hash(id)
     };
-    return (RRDDIM *)avl_search_lock(&(st->dimensions_index), (avl *) &tmp);
+    return (RRDDIM *)avl_search_lock(&(st->dimensions_index), (avl_t *) &tmp);
 }
 
 
@@ -197,7 +197,7 @@ void rrdcalc_link_to_rrddim(RRDDIM *rd, RRDSET *st, RRDHOST *host) {
                     RRDCALC *child = rrdcalc_create_from_rrdcalc(rrdc, host, usename, rd->name);
                     if (child) {
                         rrdcalc_add_to_host(host, child);
-                        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_health_log,(avl *)child);
+                        RRDCALC *rdcmp  = (RRDCALC *) avl_insert_lock(&(host)->alarms_idx_health_log,(avl_t *)child);
                         if (rdcmp != child) {
                             error("Cannot insert the alarm index ID %s",child->name);
                         }
@@ -232,9 +232,7 @@ RRDDIM *rrddim_add_custom(RRDSET *st, const char *id, const char *name, collecte
         rc += rrddim_set_multiplier(st, rd, multiplier);
         rc += rrddim_set_divisor(st, rd, divisor);
         if (rrddim_flag_check(rd, RRDDIM_FLAG_ARCHIVED)) {
-#ifdef ENABLE_DBENGINE
             store_active_dimension(rd->state->metric_uuid);
-#endif
             rd->state->collect_ops.init(rd);
             rrddim_flag_clear(rd, RRDDIM_FLAG_ARCHIVED);
             rrddimvar_create(rd, RRDVAR_TYPE_CALCULATED, NULL, NULL, &rd->last_stored_value, RRDVAR_OPTION_DEFAULT);
@@ -242,14 +240,11 @@ RRDDIM *rrddim_add_custom(RRDSET *st, const char *id, const char *name, collecte
             rrddimvar_create(rd, RRDVAR_TYPE_TIME_T, NULL, "_last_collected_t", &rd->last_collected_time.tv_sec, RRDVAR_OPTION_DEFAULT);
             calc_link_to_rrddim(rd);
         }
-        // DBENGINE available and activated?
-#ifdef ENABLE_DBENGINE
-        if (likely(rd->rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE) && unlikely(rc)) {
+        if (unlikely(rc)) {
             debug(D_METADATALOG, "DIMENSION [%s] metadata updated", rd->id);
             (void)sql_store_dimension(rd->state->metric_uuid, rd->rrdset->chart_uuid, rd->id, rd->name, rd->multiplier, rd->divisor,
                                       rd->algorithm);
         }
-#endif
         rrdset_unlock(st);
         return rd;
     }
@@ -277,7 +272,7 @@ RRDDIM *rrddim_add_custom(RRDSET *st, const char *id, const char *name, collecte
         if(likely(rd)) {
             // we have a file mapped for rd
 
-            memset(&rd->avl, 0, sizeof(avl));
+            memset(&rd->avl, 0, sizeof(avl_t));
             rd->id = NULL;
             rd->name = NULL;
             rd->cache_filename = NULL;
@@ -396,7 +391,6 @@ RRDDIM *rrddim_add_custom(RRDSET *st, const char *id, const char *name, collecte
 #ifdef ENABLE_DBENGINE
         uuid_t *dim_uuid = find_dimension_uuid(st, rd);
         rrdeng_metric_init(rd, dim_uuid);
-        store_active_dimension(rd->state->metric_uuid);
         rd->state->collect_ops.init = rrdeng_store_metric_init;
         rd->state->collect_ops.store_metric = rrdeng_store_metric_next;
         rd->state->collect_ops.finalize = rrdeng_store_metric_finalize;
@@ -408,6 +402,9 @@ RRDDIM *rrddim_add_custom(RRDSET *st, const char *id, const char *name, collecte
         rd->state->query_ops.oldest_time = rrdeng_metric_oldest_time;
 #endif
     } else {
+        rd->state->metric_uuid = find_dimension_uuid(st, rd);
+        if (unlikely(!rd->state->metric_uuid))
+            rd->state->metric_uuid = create_dimension_uuid(rd->rrdset, rd);
         rd->state->collect_ops.init         = rrddim_collect_init;
         rd->state->collect_ops.store_metric = rrddim_collect_store_metric;
         rd->state->collect_ops.finalize     = rrddim_collect_finalize;
@@ -418,6 +415,7 @@ RRDDIM *rrddim_add_custom(RRDSET *st, const char *id, const char *name, collecte
         rd->state->query_ops.latest_time    = rrddim_query_latest_time;
         rd->state->query_ops.oldest_time    = rrddim_query_oldest_time;
     }
+    store_active_dimension(rd->state->metric_uuid);
     rd->state->collect_ops.init(rd);
     // append this dimension
     if(!st->dimensions)
@@ -425,7 +423,7 @@ RRDDIM *rrddim_add_custom(RRDSET *st, const char *id, const char *name, collecte
     else {
         RRDDIM *td = st->dimensions;
 
-        if(td->algorithm != rd->algorithm || abs(td->multiplier) != abs(rd->multiplier) || abs(td->divisor) != abs(rd->divisor)) {
+        if(td->algorithm != rd->algorithm || ABS(td->multiplier) != ABS(rd->multiplier) || ABS(td->divisor) != ABS(rd->divisor)) {
             if(!rrdset_flag_check(st, RRDSET_FLAG_HETEROGENEOUS)) {
                 #ifdef NETDATA_INTERNAL_CHECKS
                 info("Dimension '%s' added on chart '%s' of host '%s' is not homogeneous to other dimensions already present (algorithm is '%s' vs '%s', multiplier is " COLLECTED_NUMBER_FORMAT " vs " COLLECTED_NUMBER_FORMAT ", divisor is " COLLECTED_NUMBER_FORMAT " vs " COLLECTED_NUMBER_FORMAT ").",
@@ -476,10 +474,8 @@ void rrddim_free_custom(RRDSET *st, RRDDIM *rd, int db_rotated)
     if (!rrddim_flag_check(rd, RRDDIM_FLAG_ARCHIVED)) {
         uint8_t can_delete_metric = rd->state->collect_ops.finalize(rd);
         if (can_delete_metric && rd->rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE) {
-#ifdef ENABLE_DBENGINE
             /* This metric has no data and no references */
             delete_dimension_uuid(rd->state->metric_uuid);
-#endif
         }
     }
 
@@ -503,6 +499,7 @@ void rrddim_free_custom(RRDSET *st, RRDDIM *rd, int db_rotated)
         error("RRDDIM: INTERNAL ERROR: attempt to remove from index dimension '%s' on chart '%s', removed a different dimension.", rd->id, st->id);
 
     // free(rd->annotations);
+    freez(rd->state->metric_uuid);
 
     RRD_MEMORY_MODE rrd_memory_mode = rd->rrd_memory_mode;
     switch(rrd_memory_mode) {
@@ -522,11 +519,6 @@ void rrddim_free_custom(RRDSET *st, RRDDIM *rd, int db_rotated)
             debug(D_RRD_CALLS, "Removing dimension '%s'.", rd->name);
             freez((void *)rd->id);
             freez(rd->cache_filename);
-#ifdef ENABLE_DBENGINE
-            if (rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE) {
-                freez(rd->state->metric_uuid);
-            }
-#endif
             freez(rd->state);
             freez(rd);
             break;
diff --git a/database/rrdfamily.c b/database/rrdfamily.c
index f75f0adc3..3d91c3788 100644
--- a/database/rrdfamily.c
+++ b/database/rrdfamily.c
@@ -12,15 +12,15 @@ int rrdfamily_compare(void *a, void *b) {
     else return strcmp(((RRDFAMILY *)a)->family, ((RRDFAMILY *)b)->family);
 }
 
-#define rrdfamily_index_add(host, rc) (RRDFAMILY *)avl_insert_lock(&((host)->rrdfamily_root_index), (avl *)(rc))
-#define rrdfamily_index_del(host, rc) (RRDFAMILY *)avl_remove_lock(&((host)->rrdfamily_root_index), (avl *)(rc))
+#define rrdfamily_index_add(host, rc) (RRDFAMILY *)avl_insert_lock(&((host)->rrdfamily_root_index), (avl_t *)(rc))
+#define rrdfamily_index_del(host, rc) (RRDFAMILY *)avl_remove_lock(&((host)->rrdfamily_root_index), (avl_t *)(rc))
 
 static RRDFAMILY *rrdfamily_index_find(RRDHOST *host, const char *id, uint32_t hash) {
     RRDFAMILY tmp;
     tmp.family = id;
     tmp.hash_family = (hash)?hash:simple_hash(tmp.family);
 
-    return (RRDFAMILY *)avl_search_lock(&(host->rrdfamily_root_index), (avl *) &tmp);
+    return (RRDFAMILY *)avl_search_lock(&(host->rrdfamily_root_index), (avl_t *) &tmp);
 }
 
 RRDFAMILY *rrdfamily_create(RRDHOST *host, const char *id) {
diff --git a/database/rrdhost.c b/database/rrdhost.c
index 45c314602..ae49036a8 100644
--- a/database/rrdhost.c
+++ b/database/rrdhost.c
@@ -31,7 +31,7 @@ RRDHOST *rrdhost_find_by_guid(const char *guid, uint32_t hash) {
     strncpyz(tmp.machine_guid, guid, GUID_LEN);
     tmp.hash_machine_guid = (hash)?hash:simple_hash(tmp.machine_guid);
 
-    return (RRDHOST *)avl_search_lock(&(rrdhost_root_index), (avl *) &tmp);
+    return (RRDHOST *)avl_search_lock(&(rrdhost_root_index), (avl_t *) &tmp);
 }
 
 RRDHOST *rrdhost_find_by_hostname(const char *hostname, uint32_t hash) {
@@ -53,8 +53,8 @@ RRDHOST *rrdhost_find_by_hostname(const char *hostname, uint32_t hash) {
     return NULL;
 }
 
-#define rrdhost_index_add(rrdhost) (RRDHOST *)avl_insert_lock(&(rrdhost_root_index), (avl *)(rrdhost))
-#define rrdhost_index_del(rrdhost) (RRDHOST *)avl_remove_lock(&(rrdhost_root_index), (avl *)(rrdhost))
+#define rrdhost_index_add(rrdhost) (RRDHOST *)avl_insert_lock(&(rrdhost_root_index), (avl_t *)(rrdhost))
+#define rrdhost_index_del(rrdhost) (RRDHOST *)avl_remove_lock(&(rrdhost_root_index), (avl_t *)(rrdhost))
 
 
 // ----------------------------------------------------------------------------
@@ -298,15 +298,16 @@ RRDHOST *rrdhost_create(const char *hostname,
         return NULL;
     }
 
+    if (likely(!uuid_parse(host->machine_guid, host->host_uuid))) {
+        int rc = sql_store_host(&host->host_uuid, hostname, registry_hostname, update_every, os, timezone, tags);
+        if (unlikely(rc))
+            error_report("Failed to store machine GUID to the database");
+    }
+    else
+        error_report("Host machine GUID %s is not valid", host->machine_guid);
+
     if (host->rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE) {
 #ifdef ENABLE_DBENGINE
-        if (likely(!uuid_parse(host->machine_guid, host->host_uuid))) {
-            int rc = sql_store_host(&host->host_uuid, hostname, registry_hostname, update_every, os, timezone, tags);
-            if (unlikely(rc))
-                error_report("Failed to store machine GUID to the database");
-        }
-        else
-            error_report("Host machine GUID %s is not valid", host->machine_guid);
         char dbenginepath[FILENAME_MAX + 1];
         int ret;
 
@@ -335,6 +336,11 @@ RRDHOST *rrdhost_create(const char *hostname,
         fatal("RRD_MEMORY_MODE_DBENGINE is not supported in this platform.");
 #endif
     }
+    else {
+#ifdef ENABLE_DBENGINE
+        host->rrdeng_ctx = &multidb_ctx;
+#endif
+    }
 
     // ------------------------------------------------------------------------
     // link it and add it to the index
@@ -582,8 +588,8 @@ RRDHOST *rrdhost_find_or_create(
 
     return host;
 }
-inline int rrdhost_should_be_removed(RRDHOST *host, RRDHOST *protected, time_t now) {
-    if(host != protected
+inline int rrdhost_should_be_removed(RRDHOST *host, RRDHOST *protected_host, time_t now) {
+    if(host != protected_host
        && host != localhost
        && rrdhost_flag_check(host, RRDHOST_FLAG_ORPHAN)
        && host->receiver
@@ -594,14 +600,14 @@ inline int rrdhost_should_be_removed(RRDHOST *host, RRDHOST *protected, time_t n
     return 0;
 }
 
-void rrdhost_cleanup_orphan_hosts_nolock(RRDHOST *protected) {
+void rrdhost_cleanup_orphan_hosts_nolock(RRDHOST *protected_host) {
     time_t now = now_realtime_sec();
 
     RRDHOST *host;
 
 restart_after_removal:
     rrdhost_foreach_write(host) {
-        if(rrdhost_should_be_removed(host, protected, now)) {
+        if(rrdhost_should_be_removed(host, protected_host, now)) {
             info("Host '%s' with machine guid '%s' is obsolete - cleaning up.", host->hostname, host->machine_guid);
 
             if (rrdhost_flag_check(host, RRDHOST_FLAG_DELETE_ORPHAN_HOST)
@@ -629,11 +635,11 @@ int rrd_init(char *hostname, struct rrdhost_system_info *system_info) {
     if (gap_when_lost_iterations_above < 1)
         gap_when_lost_iterations_above = 1;
 
-#ifdef ENABLE_DBENGINE
     if (unlikely(sql_init_database())) {
-        return 1;
+        if (default_rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE)
+            return 1;
+        info("Skipping SQLITE metadata initialization since memory mode is not db engine");
     }
-#endif
 
     health_init();
 
diff --git a/database/rrdset.c b/database/rrdset.c
index d16fe737c..15640d3ed 100644
--- a/database/rrdset.c
+++ b/database/rrdset.c
@@ -35,7 +35,7 @@ static RRDSET *rrdset_index_find(RRDHOST *host, const char *id, uint32_t hash) {
     strncpyz(tmp.id, id, RRD_ID_LENGTH_MAX);
     tmp.hash = (hash)?hash:simple_hash(tmp.id);
 
-    return (RRDSET *)avl_search_lock(&(host->rrdset_root_index), (avl *) &tmp);
+    return (RRDSET *)avl_search_lock(&(host->rrdset_root_index), (avl_t *) &tmp);
 }
 
 // ----------------------------------------------------------------------------
@@ -57,7 +57,7 @@ int rrdset_compare_name(void* a, void* b) {
 RRDSET *rrdset_index_add_name(RRDHOST *host, RRDSET *st) {
     void *result;
     // fprintf(stderr, "ADDING: %s (name: %s)\n", st->id, st->name);
-    result = avl_insert_lock(&host->rrdset_root_index_name, (avl *) (&st->avlname));
+    result = avl_insert_lock(&host->rrdset_root_index_name, (avl_t *) (&st->avlname));
     if(result) return rrdset_from_avlname(result);
     return NULL;
 }
@@ -65,7 +65,7 @@ RRDSET *rrdset_index_add_name(RRDHOST *host, RRDSET *st) {
 RRDSET *rrdset_index_del_name(RRDHOST *host, RRDSET *st) {
     void *result;
     // fprintf(stderr, "DELETING: %s (name: %s)\n", st->id, st->name);
-    result = (RRDSET *)avl_remove_lock(&((host)->rrdset_root_index_name), (avl *)(&st->avlname));
+    result = (RRDSET *)avl_remove_lock(&((host)->rrdset_root_index_name), (avl_t *)(&st->avlname));
     if(result) return rrdset_from_avlname(result);
     return NULL;
 }
@@ -81,7 +81,7 @@ static inline RRDSET *rrdset_index_find_name(RRDHOST *host, const char *name, ui
     tmp.hash_name = (hash)?hash:simple_hash(tmp.name);
 
     // fprintf(stderr, "SEARCHING: %s\n", name);
-    result = avl_search_lock(&host->rrdset_root_index_name, (avl *) (&(tmp.avlname)));
+    result = avl_search_lock(&host->rrdset_root_index_name, (avl_t *) (&(tmp.avlname)));
     if(result) {
         RRDSET *st = rrdset_from_avlname(result);
         if(strcmp(st->magic, RRDSET_MAGIC) != 0)
@@ -219,11 +219,11 @@ inline void rrdset_update_heterogeneous_flag(RRDSET *st) {
     rrdset_flag_clear(st, RRDSET_FLAG_HOMOGENEOUS_CHECK);
 
     RRD_ALGORITHM algorithm = st->dimensions->algorithm;
-    collected_number multiplier = abs(st->dimensions->multiplier);
-    collected_number divisor = abs(st->dimensions->divisor);
+    collected_number multiplier = ABS(st->dimensions->multiplier);
+    collected_number divisor = ABS(st->dimensions->divisor);
 
     rrddim_foreach_read(rd, st) {
-        if(algorithm != rd->algorithm || multiplier != abs(rd->multiplier) || divisor != abs(rd->divisor)) {
+        if(algorithm != rd->algorithm || multiplier != ABS(rd->multiplier) || divisor != ABS(rd->divisor)) {
             if(!rrdset_flag_check(st, RRDSET_FLAG_HETEROGENEOUS)) {
                 #ifdef NETDATA_INTERNAL_CHECKS
                 info("Dimension '%s' added on chart '%s' of host '%s' is not homogeneous to other dimensions already present (algorithm is '%s' vs '%s', multiplier is " COLLECTED_NUMBER_FORMAT " vs " COLLECTED_NUMBER_FORMAT ", divisor is " COLLECTED_NUMBER_FORMAT " vs " COLLECTED_NUMBER_FORMAT ").",
@@ -385,6 +385,7 @@ void rrdset_free(RRDSET *st) {
     freez(st->state->old_context);
     free_label_list(st->state->labels.head);
     freez(st->state);
+    freez(st->chart_uuid);
 
     switch(st->rrd_memory_mode) {
         case RRD_MEMORY_MODE_SAVE:
@@ -397,10 +398,6 @@ void rrdset_free(RRDSET *st) {
         case RRD_MEMORY_MODE_ALLOC:
         case RRD_MEMORY_MODE_NONE:
         case RRD_MEMORY_MODE_DBENGINE:
-#ifdef ENABLE_DBENGINE
-            if (st->rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE)
-                freez(st->chart_uuid);
-#endif
             freez(st);
             break;
     }
@@ -660,15 +657,12 @@ RRDSET *rrdset_create_custom(
                 sched_yield();
             }
         }
-#ifdef ENABLE_DBENGINE
-        if (st->rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE &&
-            (mark_rebuild & (META_CHART_UPDATED | META_PLUGIN_UPDATED | META_MODULE_UPDATED))) {
+        if (mark_rebuild & (META_CHART_UPDATED | META_PLUGIN_UPDATED | META_MODULE_UPDATED)) {
             debug(D_METADATALOG, "CHART [%s] metadata updated", st->id);
             int rc = update_chart_metadata(st->chart_uuid, st, id, name);
             if (unlikely(rc))
                 error_report("Failed to update chart metadata in the database");
         }
-#endif
         /* Fall-through during switch from archived to active so that the host lock is taken and health is linked */
         if (!changed_from_archived_to_active)
             return st;
@@ -744,8 +738,8 @@ RRDSET *rrdset_create_custom(
         );
 
         if(st) {
-            memset(&st->avl, 0, sizeof(avl));
-            memset(&st->avlname, 0, sizeof(avl));
+            memset(&st->avl, 0, sizeof(avl_t));
+            memset(&st->avlname, 0, sizeof(avl_t));
             memset(&st->rrdvar_root_index, 0, sizeof(avl_tree_lock));
             memset(&st->dimensions_index, 0, sizeof(avl_tree_lock));
             memset(&st->rrdset_rwlock, 0, sizeof(netdata_rwlock_t));
@@ -925,15 +919,14 @@ RRDSET *rrdset_create_custom(
 
     rrdsetcalc_link_matching(st);
     rrdcalctemplate_link_matching(st);
-#ifdef ENABLE_DBENGINE
-    if (st->rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE) {
-        st->chart_uuid = find_chart_uuid(host, type, id, name);
-        if (unlikely(!st->chart_uuid))
-            st->chart_uuid = create_chart_uuid(st, id, name);
 
-        store_active_chart(st->chart_uuid);
-    }
-#endif
+    st->chart_uuid = find_chart_uuid(host, type, id, name);
+    if (unlikely(!st->chart_uuid))
+        st->chart_uuid = create_chart_uuid(st, id, name);
+    else
+        update_chart_metadata(st->chart_uuid, st, id, name);
+
+    store_active_chart(st->chart_uuid);
 
     rrdhost_cleanup_obsolete_charts(host);
 
@@ -1932,6 +1925,15 @@ void rrdset_finalize_labels(RRDSET *st)
     } else {
         replace_label_list(labels, new_labels);
     }
+
+    netdata_rwlock_wrlock(&labels->labels_rwlock);
+    struct label *lbl = labels->head;
+    while (lbl) {
+        sql_store_chart_label(st->chart_uuid, (int)lbl->label_source, lbl->key, lbl->value);
+        lbl = lbl->next;
+    }
+    netdata_rwlock_unlock(&labels->labels_rwlock);
+
     st->state->new_labels = NULL;
 }
 
diff --git a/database/rrdvar.c b/database/rrdvar.c
index 6b824d0d3..25b8ca69e 100644
--- a/database/rrdvar.c
+++ b/database/rrdvar.c
@@ -27,7 +27,7 @@ int rrdvar_compare(void* a, void* b) {
 }
 
 static inline RRDVAR *rrdvar_index_add(avl_tree_lock *tree, RRDVAR *rv) {
-    RRDVAR *ret = (RRDVAR *)avl_insert_lock(tree, (avl *)(rv));
+    RRDVAR *ret = (RRDVAR *)avl_insert_lock(tree, (avl_t *)(rv));
     if(ret != rv)
         debug(D_VARIABLES, "Request to insert RRDVAR '%s' into index failed. Already exists.", rv->name);
 
@@ -35,7 +35,7 @@ static inline RRDVAR *rrdvar_index_add(avl_tree_lock *tree, RRDVAR *rv) {
 }
 
 static inline RRDVAR *rrdvar_index_del(avl_tree_lock *tree, RRDVAR *rv) {
-    RRDVAR *ret = (RRDVAR *)avl_remove_lock(tree, (avl *)(rv));
+    RRDVAR *ret = (RRDVAR *)avl_remove_lock(tree, (avl_t *)(rv));
     if(!ret)
         error("Request to remove RRDVAR '%s' from index failed. Not Found.", rv->name);
 
@@ -47,7 +47,7 @@ static inline RRDVAR *rrdvar_index_find(avl_tree_lock *tree, const char *name, u
     tmp.name = (char *)name;
     tmp.hash = (hash)?hash:simple_hash(tmp.name);
 
-    return (RRDVAR *)avl_search_lock(tree, (avl *)&tmp);
+    return (RRDVAR *)avl_search_lock(tree, (avl_t *)&tmp);
 }
 
 inline void rrdvar_free(RRDHOST *host, avl_tree_lock *tree, RRDVAR *rv) {
diff --git a/database/rrdvar.h b/database/rrdvar.h
index 6d1461b2a..ec6e80a43 100644
--- a/database/rrdvar.h
+++ b/database/rrdvar.h
@@ -32,7 +32,7 @@ typedef enum rrdvar_options {
 // 2. at each context (RRDFAMILY.rrdvar_root_index)
 // 3. at each host    (RRDHOST.rrdvar_root_index)
 struct rrdvar {
-    avl avl;
+    avl_t avl;
 
     char *name;
     uint32_t hash;
diff --git a/database/sqlite/Makefile.am b/database/sqlite/Makefile.am
new file mode 100644
index 000000000..babdcf0df
--- /dev/null
+++ b/database/sqlite/Makefile.am
@@ -0,0 +1,4 @@
+# SPDX-License-Identifier: GPL-3.0-or-later
+
+AUTOMAKE_OPTIONS = subdir-objects
+MAINTAINERCLEANFILES = $(srcdir)/Makefile.in
diff --git a/database/sqlite/sqlite_functions.c b/database/sqlite/sqlite_functions.c
index ab6c59cfa..694b86330 100644
--- a/database/sqlite/sqlite_functions.c
+++ b/database/sqlite/sqlite_functions.c
@@ -17,12 +17,14 @@ const char *database_config[] = {
     "CREATE TABLE IF NOT EXISTS metadata_migration(filename text, file_size, date_created int);",
     "CREATE INDEX IF NOT EXISTS ind_d1 on dimension (chart_id, id, name);",
     "CREATE INDEX IF NOT EXISTS ind_c1 on chart (host_id, id, type, name);",
+    "CREATE TABLE IF NOT EXISTS chart_label(chart_id blob, source_type int, label_key text, "
+    "label_value text, date_created int, PRIMARY KEY (chart_id, label_key));",
 
     "delete from chart_active;",
     "delete from dimension_active;",
-
     "delete from chart where chart_id not in (select chart_id from dimension);",
     "delete from host where host_id not in (select host_id from chart);",
+    "delete from chart_label where chart_id not in (select chart_id from chart);",
     NULL
 };
 
@@ -46,6 +48,31 @@ static int execute_insert(sqlite3_stmt *res)
     return rc;
 }
 
+#define MAX_OPEN_STATEMENTS (512)
+
+static void add_stmt_to_list(sqlite3_stmt *res)
+{
+    static int idx = 0;
+    static sqlite3_stmt *statements[MAX_OPEN_STATEMENTS];
+
+    if (unlikely(!res)) {
+        while (idx > 0)
+            sqlite3_finalize(statements[--idx]);
+        return;
+    }
+
+    if (unlikely(idx == MAX_OPEN_STATEMENTS))
+        return;
+    statements[idx++] = res;
+}
+
+static int prepare_statement(sqlite3 *database, char *query, sqlite3_stmt **statement) {
+    int rc = sqlite3_prepare_v2(database, query, -1, statement, 0);
+    if (likely(rc == SQLITE_OK))
+        add_stmt_to_list(*statement);
+    return rc;
+}
+
 /*
  * Store a chart or dimension UUID in  chart_active or dimension_active
  * The statement that will be prepared determines that
@@ -82,7 +109,8 @@ void store_active_chart(uuid_t *chart_uuid)
     int rc;
 
     if (unlikely(!db_meta)) {
-        error_report("Database has not been initialized");
+        if (default_rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE)
+            error_report("Database has not been initialized");
         return;
     }
 
@@ -109,7 +137,8 @@ void store_active_dimension(uuid_t *dimension_uuid)
     int rc;
 
     if (unlikely(!db_meta)) {
-        error_report("Database has not been initialized");
+        if (default_rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE)
+            error_report("Database has not been initialized");
         return;
     }
 
@@ -141,7 +170,9 @@ int sql_init_database(void)
     snprintfz(sqlite_database, FILENAME_MAX, "%s/netdata-meta.db", netdata_configured_cache_dir);
     rc = sqlite3_open(sqlite_database, &db_meta);
     if (rc != SQLITE_OK) {
-        error_report("Failed to initialize database at %s", sqlite_database);
+        error_report("Failed to initialize database at %s, due to \"%s\"", sqlite_database, sqlite3_errstr(rc));
+        sqlite3_close(db_meta);
+        db_meta = NULL;
         return 1;
     }
 
@@ -172,9 +203,12 @@ void sql_close_database(void)
         return;
 
     info("Closing SQLite database");
-    rc = sqlite3_close(db_meta);
+
+    add_stmt_to_list(NULL);
+
+    rc = sqlite3_close_v2(db_meta);
     if (unlikely(rc != SQLITE_OK))
-        error_report("Error %d while closing the SQLite database", rc);
+        error_report("Error %d while closing the SQLite database, %s", rc, sqlite3_errstr(rc));
     return;
 }
 
@@ -187,7 +221,7 @@ int find_uuid_type(uuid_t *uuid)
     int uuid_type = 3;
 
     if (unlikely(!res)) {
-        rc = sqlite3_prepare_v2(db_meta, FIND_UUID_TYPE, -1, &res, 0);
+        rc = prepare_statement(db_meta, FIND_UUID_TYPE, &res);
         if (rc != SQLITE_OK) {
             error_report("Failed to bind prepare statement to find UUID type in the database");
             return 0;
@@ -218,8 +252,11 @@ uuid_t *find_dimension_uuid(RRDSET *st, RRDDIM *rd)
     uuid_t *uuid = NULL;
     int rc;
 
+    if (unlikely(!db_meta) && default_rrd_memory_mode != RRD_MEMORY_MODE_DBENGINE)
+        return NULL;
+
     if (unlikely(!res)) {
-        rc = sqlite3_prepare_v2(db_meta, SQL_FIND_DIMENSION_UUID, -1, &res, 0);
+        rc = prepare_statement(db_meta, SQL_FIND_DIMENSION_UUID, &res);
         if (rc != SQLITE_OK) {
             error_report("Failed to bind prepare statement to lookup dimension UUID in the database");
             return NULL;
@@ -299,7 +336,7 @@ void delete_dimension_uuid(uuid_t *dimension_uuid)
 #endif
 
     if (unlikely(!res)) {
-        rc = sqlite3_prepare_v2(db_meta, DELETE_DIMENSION_UUID, -1, &res, 0);
+        rc = prepare_statement(db_meta, DELETE_DIMENSION_UUID, &res);
         if (rc != SQLITE_OK) {
             error_report("Failed to prepare statement to delete a dimension uuid");
             return;
@@ -331,8 +368,11 @@ uuid_t *find_chart_uuid(RRDHOST *host, const char *type, const char *id, const c
     uuid_t *uuid = NULL;
     int rc;
 
+    if (unlikely(!db_meta) && default_rrd_memory_mode != RRD_MEMORY_MODE_DBENGINE)
+        return NULL;
+
     if (unlikely(!res)) {
-        rc = sqlite3_prepare_v2(db_meta, SQL_FIND_CHART_UUID, -1, &res, 0);
+        rc = prepare_statement(db_meta, SQL_FIND_CHART_UUID, &res);
         if (rc != SQLITE_OK) {
             error_report("Failed to prepare statement to lookup chart UUID in the database");
             return NULL;
@@ -388,6 +428,9 @@ int update_chart_metadata(uuid_t *chart_uuid, RRDSET *st, const char *id, const
 {
     int rc;
 
+    if (unlikely(!db_meta) && default_rrd_memory_mode != RRD_MEMORY_MODE_DBENGINE)
+        return 0;
+
     rc = sql_store_chart(
         chart_uuid, &st->rrdhost->host_uuid, st->type, id, name, st->family, st->context, st->title, st->units, st->plugin_name,
         st->module_name, st->priority, st->update_every, st->chart_type, st->rrd_memory_mode, st->entries);
@@ -427,12 +470,14 @@ int sql_store_host(
     int rc;
 
     if (unlikely(!db_meta)) {
+        if (default_rrd_memory_mode != RRD_MEMORY_MODE_DBENGINE)
+            return 0;
         error_report("Database has not been initialized");
         return 1;
     }
 
     if (unlikely((!res))) {
-        rc = sqlite3_prepare_v2(db_meta, SQL_STORE_HOST, -1, &res, 0);
+        rc = prepare_statement(db_meta, SQL_STORE_HOST, &res);
         if (unlikely(rc != SQLITE_OK)) {
             error_report("Failed to prepare statement to store host, rc = %d", rc);
             return 1;
@@ -493,16 +538,18 @@ int sql_store_chart(
     const char *context, const char *title, const char *units, const char *plugin, const char *module, long priority,
     int update_every, int chart_type, int memory_mode, long history_entries)
 {
-    static __thread sqlite3_stmt *res;
+    static __thread sqlite3_stmt *res = NULL;
     int rc, param = 0;
 
     if (unlikely(!db_meta)) {
+        if (default_rrd_memory_mode != RRD_MEMORY_MODE_DBENGINE)
+            return 0;
         error_report("Database has not been initialized");
         return 1;
     }
 
     if (unlikely(!res)) {
-        rc = sqlite3_prepare_v2(db_meta, SQL_STORE_CHART, -1, &res, 0);
+        rc = prepare_statement(db_meta, SQL_STORE_CHART, &res);
         if (unlikely(rc != SQLITE_OK)) {
             error_report("Failed to prepare statement to store chart, rc = %d", rc);
             return 1;
@@ -530,11 +577,12 @@ int sql_store_chart(
         goto bind_fail;
 
     param++;
-    if (name) {
+    if (name && *name)
         rc = sqlite3_bind_text(res, 5, name, -1, SQLITE_STATIC);
-        if (unlikely(rc != SQLITE_OK))
-            goto bind_fail;
-    }
+    else
+        rc = sqlite3_bind_null(res, 5);
+    if (unlikely(rc != SQLITE_OK))
+        goto bind_fail;
 
     param++;
     rc = sqlite3_bind_text(res, 6, family, -1, SQLITE_STATIC);
@@ -620,12 +668,14 @@ int sql_store_dimension(
     int rc;
 
     if (unlikely(!db_meta)) {
+        if (default_rrd_memory_mode != RRD_MEMORY_MODE_DBENGINE)
+            return 0;
         error_report("Database has not been initialized");
         return 1;
     }
 
     if (unlikely(!res)) {
-        rc = sqlite3_prepare_v2(db_meta, SQL_STORE_DIMENSION, -1, &res, 0);
+        rc = prepare_statement(db_meta, SQL_STORE_DIMENSION, &res);
         if (unlikely(rc != SQLITE_OK)) {
             error_report("Failed to prepare statement to store dimension, rc = %d", rc);
             return 1;
@@ -733,7 +783,7 @@ void sql_rrdset2json(RRDHOST *host, BUFFER *wb)
     rc = sqlite3_bind_blob(res_chart, 1, &host->host_uuid, sizeof(host->host_uuid), SQLITE_STATIC);
     if (unlikely(rc != SQLITE_OK)) {
         error_report("Failed to bind host parameter to fetch archived charts");
-        return;
+        goto failed;
     }
 
     rc = sqlite3_prepare_v2(db_meta, SELECT_DIMENSION, -1, &res_dim, 0);
@@ -883,25 +933,41 @@ failed:
     return;
 }
 
-#define SELECT_HOST "select host_id, registry_hostname, update_every, os, timezone, tags from host where hostname = @hostname;"
+#define SELECT_HOST "select host_id, registry_hostname, update_every, os, timezone, tags from host where hostname = @hostname order by rowid desc;"
+#define SELECT_HOST_BY_UUID "select host_id, registry_hostname, update_every, os, timezone, tags from host where host_id = @host_id ;"
 
 RRDHOST *sql_create_host_by_uuid(char *hostname)
 {
     int rc;
     RRDHOST *host = NULL;
+    uuid_t host_uuid;
 
     sqlite3_stmt *res = NULL;
 
-    rc = sqlite3_prepare_v2(db_meta, SELECT_HOST, -1, &res, 0);
-    if (unlikely(rc != SQLITE_OK)) {
-        error_report("Failed to prepare statement to fetch host");
-        return NULL;
+    rc = uuid_parse(hostname, host_uuid);
+    if (!rc) {
+        rc = sqlite3_prepare_v2(db_meta, SELECT_HOST_BY_UUID, -1, &res, 0);
+        if (unlikely(rc != SQLITE_OK)) {
+            error_report("Failed to prepare statement to fetch host by uuid");
+            return NULL;
+        }
+        rc = sqlite3_bind_blob(res, 1, &host_uuid, sizeof(host_uuid), SQLITE_STATIC);
+        if (unlikely(rc != SQLITE_OK)) {
+            error_report("Failed to bind host_id parameter to fetch host information");
+            goto failed;
+        }
     }
-
-    rc = sqlite3_bind_text(res, 1, hostname, -1, SQLITE_STATIC);
-    if (unlikely(rc != SQLITE_OK)) {
-        error_report("Failed to bind hostname parameter to fetch host information");
-        return NULL;
+    else {
+        rc = sqlite3_prepare_v2(db_meta, SELECT_HOST, -1, &res, 0);
+        if (unlikely(rc != SQLITE_OK)) {
+            error_report("Failed to prepare statement to fetch host by hostname");
+            return NULL;
+        }
+        rc = sqlite3_bind_text(res, 1, hostname, -1, SQLITE_STATIC);
+        if (unlikely(rc != SQLITE_OK)) {
+            error_report("Failed to bind hostname parameter to fetch host information");
+            goto failed;
+        }
     }
 
     rc = sqlite3_step(res);
@@ -916,13 +982,17 @@ RRDHOST *sql_create_host_by_uuid(char *hostname)
     host = callocz(1, sizeof(RRDHOST));
 
     set_host_properties(host, sqlite3_column_int(res, 2), RRD_MEMORY_MODE_DBENGINE, hostname,
-                            (char *) sqlite3_column_text(res, 1), (const char *) uuid_str,
+                        (char *) sqlite3_column_text(res, 1), (const char *) uuid_str,
                         (char *) sqlite3_column_text(res, 3), (char *) sqlite3_column_text(res, 5),
                         (char *) sqlite3_column_text(res, 4), NULL, NULL);
 
     uuid_copy(host->host_uuid, *((uuid_t *) sqlite3_column_blob(res, 0)));
 
-    host->system_info = NULL;
+    host->system_info = callocz(1, sizeof(*host->system_info));;
+    rrdhost_flag_set(host, RRDHOST_FLAG_ARCHIVED);
+#ifdef ENABLE_DBENGINE
+    host->rrdeng_ctx = &multidb_ctx;
+#endif
 
 failed:
     rc = sqlite3_finalize(res);
@@ -1020,3 +1090,251 @@ void add_migrated_file(char *path, uint64_t file_size)
 
     return;
 }
+
+#define SQL_INS_CHART_LABEL "insert or replace into chart_label " \
+    "(chart_id, source_type, label_key, label_value, date_created) " \
+    "values (@chart, @source, @label, @value, strftime('%s'));"
+
+void sql_store_chart_label(uuid_t *chart_uuid, int source_type, char *label, char *value)
+{
+    sqlite3_stmt *res = NULL;
+    int rc;
+
+    if (unlikely(!db_meta)) {
+        if (default_rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE)
+            error_report("Database has not been initialized");
+        return;
+    }
+
+    rc = sqlite3_prepare_v2(db_meta, SQL_INS_CHART_LABEL, -1, &res, 0);
+    if (unlikely(rc != SQLITE_OK)) {
+        error_report("Failed to prepare statement store chart labels");
+        return;
+    }
+
+    rc = sqlite3_bind_blob(res, 1, chart_uuid, sizeof(*chart_uuid), SQLITE_STATIC);
+    if (unlikely(rc != SQLITE_OK)) {
+        error_report("Failed to bind chart_id parameter to store label information");
+        goto failed;
+    }
+
+    rc = sqlite3_bind_int(res, 2, source_type);
+    if (unlikely(rc != SQLITE_OK)) {
+        error_report("Failed to bind type parameter to store label information");
+        goto failed;
+    }
+
+    rc = sqlite3_bind_text(res, 3, label, -1, SQLITE_STATIC);
+    if (unlikely(rc != SQLITE_OK)) {
+        error_report("Failed to bind label parameter to store label information");
+        goto failed;
+    }
+
+    rc = sqlite3_bind_text(res, 4, value, -1, SQLITE_STATIC);
+    if (unlikely(rc != SQLITE_OK)) {
+        error_report("Failed to bind value parameter to store label information");
+        goto failed;
+    }
+
+    rc = execute_insert(res);
+    if (unlikely(rc != SQLITE_DONE))
+        error_report("Failed to store chart label entry, rc = %d", rc);
+
+failed:
+    if (unlikely(sqlite3_finalize(res) != SQLITE_OK))
+        error_report("Failed to finalize the prepared statement when storing chart label information");
+
+    return;
+}
+
+int find_dimension_first_last_t(char *machine_guid, char *chart_id, char *dim_id,
+                                uuid_t *uuid, time_t *first_entry_t, time_t *last_entry_t, uuid_t *rrdeng_uuid)
+{
+#ifdef ENABLE_DBENGINE
+    int rc;
+    uuid_t  legacy_uuid;
+    uuid_t  multihost_legacy_uuid;
+    time_t dim_first_entry_t, dim_last_entry_t;
+
+    rc = rrdeng_metric_latest_time_by_uuid(uuid, &dim_first_entry_t, &dim_last_entry_t);
+    if (unlikely(rc)) {
+        rrdeng_generate_legacy_uuid(dim_id, chart_id, &legacy_uuid);
+        rc = rrdeng_metric_latest_time_by_uuid(&legacy_uuid, &dim_first_entry_t, &dim_last_entry_t);
+        if (likely(rc)) {
+            rrdeng_convert_legacy_uuid_to_multihost(machine_guid, &legacy_uuid, &multihost_legacy_uuid);
+            rc = rrdeng_metric_latest_time_by_uuid(&multihost_legacy_uuid, &dim_first_entry_t, &dim_last_entry_t);
+            if (likely(!rc))
+                uuid_copy(*rrdeng_uuid, multihost_legacy_uuid);
+        }
+        else
+            uuid_copy(*rrdeng_uuid, legacy_uuid);
+    }
+    else
+        uuid_copy(*rrdeng_uuid, *uuid);
+
+    if (likely(!rc)) {
+        *first_entry_t = MIN(*first_entry_t, dim_first_entry_t);
+        *last_entry_t = MAX(*last_entry_t, dim_last_entry_t);
+    }
+    return rc;
+#else
+    UNUSED(machine_guid);
+    UNUSED(chart_id);
+    UNUSED(dim_id);
+    UNUSED(uuid);
+    UNUSED(first_entry_t);
+    UNUSED(last_entry_t);
+    UNUSED(rrdeng_uuid);
+    return 1;
+#endif
+}
+
+#ifdef ENABLE_DBENGINE
+static RRDDIM *create_rrdim_entry(RRDSET *st, char *id, char *name, uuid_t *metric_uuid)
+{
+    RRDDIM *rd = callocz(1, sizeof(*rd));
+    rd->rrdset = st;
+    rd->last_stored_value = NAN;
+    rrddim_flag_set(rd, RRDDIM_FLAG_NONE);
+    rd->state = mallocz(sizeof(*rd->state));
+    rd->rrd_memory_mode = RRD_MEMORY_MODE_DBENGINE;
+    rd->state->query_ops.init = rrdeng_load_metric_init;
+    rd->state->query_ops.next_metric = rrdeng_load_metric_next;
+    rd->state->query_ops.is_finished = rrdeng_load_metric_is_finished;
+    rd->state->query_ops.finalize = rrdeng_load_metric_finalize;
+    rd->state->query_ops.latest_time = rrdeng_metric_latest_time;
+    rd->state->query_ops.oldest_time = rrdeng_metric_oldest_time;
+    rd->state->rrdeng_uuid = mallocz(sizeof(uuid_t));
+    uuid_copy(*rd->state->rrdeng_uuid, *metric_uuid);
+    rd->state->metric_uuid = rd->state->rrdeng_uuid;
+    rd->id = strdupz(id);
+    rd->name = strdupz(name);
+    return rd;
+}
+#endif
+
+#define SELECT_CHART_CONTEXT  "select d.dim_id, d.id, d.name, c.id, c.type, c.name, c.update_every, c.chart_id from chart c, " \
+    "dimension d, host h " \
+    "where d.chart_id = c.chart_id and c.host_id = h.host_id and c.host_id = @host_id and c.context = @context " \
+    "order by c.chart_id asc, c.type||c.id desc;"
+
+#define SELECT_CHART_SINGLE  "select d.dim_id, d.id, d.name, c.id, c.type, c.name, c.update_every, c.chart_id, c.context from chart c, " \
+    "dimension d, host h " \
+    "where d.chart_id = c.chart_id and c.host_id = h.host_id and c.host_id = @host_id and c.type||'.'||c.id = @chart " \
+    "order by c.chart_id asc, c.type||'.'||c.id desc;"
+
+void sql_build_context_param_list(struct context_param **param_list, RRDHOST *host, char *context, char *chart)
+{
+#ifdef ENABLE_DBENGINE
+    int rc;
+
+    if (unlikely(!param_list) || host->rrd_memory_mode != RRD_MEMORY_MODE_DBENGINE)
+        return;
+
+    if (unlikely(!(*param_list))) {
+        *param_list = mallocz(sizeof(struct context_param));
+        (*param_list)->first_entry_t = LONG_MAX;
+        (*param_list)->last_entry_t = 0;
+        (*param_list)->rd = NULL;
+        (*param_list)->flags = CONTEXT_FLAGS_ARCHIVE;
+        if (chart)
+            (*param_list)->flags |= CONTEXT_FLAGS_CHART;
+        else
+            (*param_list)->flags |= CONTEXT_FLAGS_CONTEXT;
+    }
+
+    sqlite3_stmt *res = NULL;
+
+    if (context)
+        rc = sqlite3_prepare_v2(db_meta, SELECT_CHART_CONTEXT, -1, &res, 0);
+    else
+        rc = sqlite3_prepare_v2(db_meta, SELECT_CHART_SINGLE, -1, &res, 0);
+    if (unlikely(rc != SQLITE_OK)) {
+        error_report("Failed to prepare statement to fetch host archived charts");
+        return;
+    }
+
+    rc = sqlite3_bind_blob(res, 1, &host->host_uuid, sizeof(host->host_uuid), SQLITE_STATIC);
+    if (unlikely(rc != SQLITE_OK)) {
+        error_report("Failed to bind host parameter to fetch archived charts");
+        goto failed;
+    }
+
+    if (context)
+        rc = sqlite3_bind_text(res, 2, context, -1, SQLITE_STATIC);
+    else
+        rc = sqlite3_bind_text(res, 2, chart, -1, SQLITE_STATIC);
+    if (unlikely(rc != SQLITE_OK)) {
+        error_report("Failed to bind host parameter to fetch archived charts");
+        goto failed;
+    }
+
+    RRDSET *st = NULL;
+    char machine_guid[GUID_LEN + 1];
+    uuid_unparse_lower(host->host_uuid, machine_guid);
+    uuid_t rrdeng_uuid;
+    uuid_t chart_id;
+
+    while (sqlite3_step(res) == SQLITE_ROW) {
+        char id[512];
+        sprintf(id, "%s.%s", sqlite3_column_text(res, 3), sqlite3_column_text(res, 1));
+
+        if (!st || uuid_compare(*(uuid_t *)sqlite3_column_blob(res, 7), chart_id)) {
+            if (unlikely(st && !st->counter)) {
+                freez(st->context);
+                freez((char *) st->name);
+                freez(st);
+            }
+            st = callocz(1, sizeof(*st));
+            char n[RRD_ID_LENGTH_MAX + 1];
+
+            snprintfz(
+                n, RRD_ID_LENGTH_MAX, "%s.%s", (char *)sqlite3_column_text(res, 4),
+                (char *)sqlite3_column_text(res, 3));
+            st->name = strdupz(n);
+            st->update_every = sqlite3_column_int(res, 6);
+            st->counter = 0;
+            if (chart) {
+                st->context = strdupz((char *)sqlite3_column_text(res, 8));
+                strncpyz(st->id, chart, RRD_ID_LENGTH_MAX);
+            }
+            uuid_copy(chart_id, *(uuid_t *)sqlite3_column_blob(res, 7));
+            st->last_entry_t = 0;
+            st->rrdhost = host;
+        }
+
+        if (unlikely(find_dimension_first_last_t(machine_guid, (char *)st->name, (char *)sqlite3_column_text(res, 1),
+                (uuid_t *)sqlite3_column_blob(res, 0), &(*param_list)->first_entry_t, &(*param_list)->last_entry_t,
+                &rrdeng_uuid)))
+            continue;
+
+        st->counter++;
+        st->last_entry_t = MAX(st->last_entry_t, (*param_list)->last_entry_t);
+
+        RRDDIM *rd = create_rrdim_entry(st, (char *)sqlite3_column_text(res, 1), (char *)sqlite3_column_text(res, 2), &rrdeng_uuid);
+        rd->next = (*param_list)->rd;
+        (*param_list)->rd = rd;
+    }
+    if (st) {
+        if (!st->counter) {
+            freez(st->context);
+            freez((char *)st->name);
+            freez(st);
+        }
+        else
+            if (!st->context && context)
+                st->context = strdupz(context);
+    }
+
+failed:
+    rc = sqlite3_finalize(res);
+    if (unlikely(rc != SQLITE_OK))
+        error_report("Failed to finalize the prepared statement when reading archived charts");
+#else
+    UNUSED(param_list);
+    UNUSED(host);
+    UNUSED(context);
+    UNUSED(chart);
+#endif
+    return;
+}
diff --git a/database/sqlite/sqlite_functions.h b/database/sqlite/sqlite_functions.h
index f0b4b775e..d2bee75d2 100644
--- a/database/sqlite/sqlite_functions.h
+++ b/database/sqlite/sqlite_functions.h
@@ -58,5 +58,6 @@ extern void add_migrated_file(char *path, uint64_t file_size);
 extern void db_unlock(void);
 extern void db_lock(void);
 extern void delete_dimension_uuid(uuid_t *dimension_uuid);
-
+extern void sql_store_chart_label(uuid_t *chart_uuid, int source_type, char *label, char *value);
+extern void sql_build_context_param_list(struct context_param **param_list, RRDHOST *host, char *context, char *chart);
 #endif //NETDATA_SQLITE_FUNCTIONS_H