netdata/database/sqlite/sqlite_functions.c

// SPDX-License-Identifier: GPL-3.0-or-later

#include "sqlite_functions.h"
#include "sqlite_db_migration.h"

#define DB_METADATA_VERSION 7

const char *database_config[] = {
    "CREATE TABLE IF NOT EXISTS host(host_id BLOB PRIMARY KEY, hostname TEXT NOT NULL, "
    "registry_hostname TEXT NOT NULL default 'unknown', update_every INT NOT NULL default 1, "
    "os TEXT NOT NULL default 'unknown', timezone TEXT NOT NULL default 'unknown', tags TEXT NOT NULL default '',"
    "hops INT NOT NULL DEFAULT 0,"
    "memory_mode INT DEFAULT 0, abbrev_timezone TEXT DEFAULT '', utc_offset INT NOT NULL DEFAULT 0,"
    "program_name TEXT NOT NULL DEFAULT 'unknown', program_version TEXT NOT NULL DEFAULT 'unknown', "
    "entries INT NOT NULL DEFAULT 0,"
    "health_enabled INT NOT NULL DEFAULT 0);",

    "CREATE TABLE IF NOT EXISTS chart(chart_id blob PRIMARY KEY, host_id blob, type text, id text, name text, "
    "family text, context text, title text, unit text, plugin text, module text, priority int, update_every int, "
    "chart_type int, memory_mode int, history_entries);",
    "CREATE TABLE IF NOT EXISTS dimension(dim_id blob PRIMARY KEY, chart_id blob, id text, name text, "
    "multiplier int, divisor int , algorithm int, options text);",

    "CREATE TABLE IF NOT EXISTS metadata_migration(filename text, file_size, date_created int);",
    "CREATE INDEX IF NOT EXISTS ind_d2 on dimension (chart_id);",
    "CREATE INDEX IF NOT EXISTS ind_c3 on chart (host_id);",
    "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));",
    "CREATE TABLE IF NOT EXISTS node_instance (host_id blob PRIMARY KEY, claim_id, node_id, date_created);",
    "CREATE TABLE IF NOT EXISTS alert_hash(hash_id blob PRIMARY KEY, date_updated int, alarm text, template text, "
    "on_key text, class text, component text, type text, os text, hosts text, lookup text, "
    "every text, units text, calc text, families text, plugin text, module text, charts text, green text, "
    "red text, warn text, crit text, exec text, to_key text, info text, delay text, options text, "
    "repeat text, host_labels text, p_db_lookup_dimensions text, p_db_lookup_method text, p_db_lookup_options int, "
    "p_db_lookup_after int, p_db_lookup_before int, p_update_every int);",

    "CREATE TABLE IF NOT EXISTS host_info(host_id blob, system_key text NOT NULL, system_value text NOT NULL, "
    "date_created INT, PRIMARY KEY(host_id, system_key));",

    "CREATE TABLE IF NOT EXISTS host_label(host_id blob, source_type int, label_key text NOT NULL, "
    "label_value text NOT NULL, date_created INT, PRIMARY KEY (host_id, label_key));",

    "CREATE TRIGGER IF NOT EXISTS ins_host AFTER INSERT ON host BEGIN INSERT INTO node_instance (host_id, date_created)"
      " SELECT new.host_id, unixepoch() WHERE new.host_id NOT IN (SELECT host_id FROM node_instance); END;",

    NULL
};

const char *database_cleanup[] = {
    "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 node_instance WHERE host_id NOT IN (SELECT host_id FROM host);",
    "DELETE FROM host_info WHERE host_id NOT IN (SELECT host_id FROM host);",
    "DELETE FROM host_label WHERE host_id NOT IN (SELECT host_id FROM host);",
    "DROP TRIGGER IF EXISTS tr_dim_del;",
    "DROP INDEX IF EXISTS ind_d1;",
    "DROP INDEX IF EXISTS ind_c1;",
    "DROP INDEX IF EXISTS ind_c2;",
    NULL
};

sqlite3 *db_meta = NULL;

#define MAX_PREPARED_STATEMENTS (32)
pthread_key_t key_pool[MAX_PREPARED_STATEMENTS];

SQLITE_API int sqlite3_exec_monitored(
    sqlite3 *db,                               /* An open database */
    const char *sql,                           /* SQL to be evaluated */
    int (*callback)(void*,int,char**,char**),  /* Callback function */
    void *data,                                /* 1st argument to callback */
    char **errmsg                              /* Error msg written here */
) {
    int rc = sqlite3_exec(db, sql, callback, data, errmsg);
    global_statistics_sqlite3_query_completed(rc == SQLITE_OK, rc == SQLITE_BUSY, rc == SQLITE_LOCKED);
    return rc;
}

SQLITE_API int sqlite3_step_monitored(sqlite3_stmt *stmt) {
    int rc;
    int cnt = 0;

    while (cnt++ < SQL_MAX_RETRY) {
        rc = sqlite3_step(stmt);
        switch (rc) {
            case SQLITE_DONE:
                global_statistics_sqlite3_query_completed(1, 0, 0);
                break;
            case SQLITE_ROW:
                global_statistics_sqlite3_row_completed();
                break;
            case SQLITE_BUSY:
            case SQLITE_LOCKED:
                global_statistics_sqlite3_query_completed(rc == SQLITE_DONE, rc == SQLITE_BUSY, rc == SQLITE_LOCKED);
                usleep(SQLITE_INSERT_DELAY * USEC_PER_MS);
                continue;
            default:
                break;
        }
        break;
    }
    return rc;
}

int execute_insert(sqlite3_stmt *res)
{
    int rc;
    int cnt = 0;
    while ((rc = sqlite3_step_monitored(res)) != SQLITE_DONE && ++cnt < SQL_MAX_RETRY && likely(!netdata_exit)) {
        if (likely(rc == SQLITE_BUSY || rc == SQLITE_LOCKED)) {
            usleep(SQLITE_INSERT_DELAY * USEC_PER_MS);
            error_report("Failed to insert/update, rc = %d -- attempt %d", rc, cnt);
        }
        else {
            error_report("SQLite error %d", rc);
            break;
        }
    }
    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)) {
        if (idx)
            info("Finilizing %d statements", idx);
        else
            info("No statements pending to finalize");
        while (idx > 0) {
            int rc;
            rc = sqlite3_finalize(statements[--idx]);
            if (unlikely(rc != SQLITE_OK))
                error_report("Failed to finalize statement during shutdown, rc = %d", rc);
        }
        return;
    }

    if (unlikely(idx == MAX_OPEN_STATEMENTS))
        return;
}

static void release_statement(void *statement)
{
    int rc;
#ifdef NETDATA_DEV_MODE
    info("Thread %d: Cleaning prepared statement on %p", gettid(), statement);
#endif
    if (unlikely(rc = sqlite3_finalize((sqlite3_stmt *) statement) != SQLITE_OK))
        error_report("Failed to finalize statement, rc = %d", rc);
}

void initialize_thread_key_pool(void)
{
    for (int i = 0; i < MAX_PREPARED_STATEMENTS; i++)
        (void)pthread_key_create(&key_pool[i], release_statement);
}

int prepare_statement(sqlite3 *database, const char *query, sqlite3_stmt **statement)
{
    static __thread uint32_t keys_used = 0;

    pthread_key_t *key = NULL;
    int ret = 1;

    if (likely(keys_used < MAX_PREPARED_STATEMENTS))
        key = &key_pool[keys_used++];

    int rc = sqlite3_prepare_v2(database, query, -1, statement, 0);
    if (likely(rc == SQLITE_OK)) {
        if (likely(key)) {
            ret = pthread_setspecific(*key, *statement);
#ifdef NETDATA_DEV_MODE
            info("Thread %d: Using key %u on statement %p", gettid(), keys_used, *statement);
#endif
        }
        if (ret)
            add_stmt_to_list(*statement);
    }
    return rc;
}

static int check_table_integrity_cb(void *data, int argc, char **argv, char **column)
{
    int *status = data;
    UNUSED(argc);
    UNUSED(column);
    info("---> %s", argv[0]);
    *status = (strcmp(argv[0], "ok") != 0);
    return 0;
}


static int check_table_integrity(char *table)
{
    int status = 0;
    char *err_msg = NULL;
    char wstr[255];

    if (table) {
        info("Checking table %s", table);
        snprintfz(wstr, 254, "PRAGMA integrity_check(%s);", table);
    }
    else {
        info("Checking entire database");
        strcpy(wstr,"PRAGMA integrity_check;");
    }

    int rc = sqlite3_exec_monitored(db_meta, wstr, check_table_integrity_cb, (void *) &status, &err_msg);
    if (rc != SQLITE_OK) {
        error_report("SQLite error during database integrity check for %s, rc = %d (%s)",
                     table ? table : "the entire database", rc, err_msg);
        sqlite3_free(err_msg);
    }

    return status;
}

const char *rebuild_chart_commands[] = {
    "BEGIN TRANSACTION; ",
    "DROP INDEX IF EXISTS ind_c1;" ,
    "DROP TABLE IF EXISTS chart_backup; " ,
    "CREATE TABLE chart_backup AS SELECT * FROM chart; " ,
    "DROP TABLE chart;  ",
    "CREATE TABLE IF NOT EXISTS chart(chart_id blob PRIMARY KEY, host_id blob, type text, id text, "
       "name text, family text, context text, title text, unit text, plugin text, "
       "module text, priority int, update_every int, chart_type int, memory_mode int, history_entries); ",
    "INSERT INTO chart SELECT DISTINCT * FROM chart_backup; ",
    "DROP TABLE chart_backup;  " ,
    "CREATE INDEX IF NOT EXISTS ind_c1 on chart (host_id, id, type, name);",
    "COMMIT TRANSACTION;",
    NULL
};

static void rebuild_chart()
{
    int rc;
    char *err_msg = NULL;
    info("Rebuilding chart table");
    for (int i = 0; rebuild_chart_commands[i]; i++) {
        info("Executing %s", rebuild_chart_commands[i]);
        rc = sqlite3_exec_monitored(db_meta, rebuild_chart_commands[i], 0, 0, &err_msg);
        if (rc != SQLITE_OK) {
            error_report("SQLite error during database setup, rc = %d (%s)", rc, err_msg);
            error_report("SQLite failed statement %s", rebuild_chart_commands[i]);
            sqlite3_free(err_msg);
        }
    }
}

const char *rebuild_dimension_commands[] = {
    "BEGIN TRANSACTION; ",
    "DROP INDEX IF EXISTS ind_d1;" ,
    "DROP TABLE IF EXISTS dimension_backup; " ,
    "CREATE TABLE dimension_backup AS SELECT * FROM dimension; " ,
    "DROP TABLE dimension; " ,
    "CREATE TABLE IF NOT EXISTS dimension(dim_id blob PRIMARY KEY, chart_id blob, id text, name text, "
        "multiplier int, divisor int , algorithm int, options text);" ,
    "INSERT INTO dimension SELECT distinct * FROM dimension_backup; " ,
    "DROP TABLE dimension_backup;  " ,
    "CREATE INDEX IF NOT EXISTS ind_d1 on dimension (chart_id, id, name);",
    "COMMIT TRANSACTION;",
    NULL
};

void rebuild_dimension()
{
    int rc;
    char *err_msg = NULL;

    info("Rebuilding dimension table");
    for (int i = 0; rebuild_dimension_commands[i]; i++) {
        info("Executing %s", rebuild_dimension_commands[i]);
        rc = sqlite3_exec_monitored(db_meta, rebuild_dimension_commands[i], 0, 0, &err_msg);
        if (rc != SQLITE_OK) {
            error_report("SQLite error during database setup, rc = %d (%s)", rc, err_msg);
            error_report("SQLite failed statement %s", rebuild_dimension_commands[i]);
            sqlite3_free(err_msg);
        }
    }
}

static int attempt_database_fix()
{
    info("Closing database and attempting to fix it");
    int rc = sqlite3_close(db_meta);
    if (rc != SQLITE_OK)
        error_report("Failed to close database, rc = %d", rc);
    info("Attempting to fix database");
    db_meta = NULL;
    return sql_init_database(DB_CHECK_FIX_DB | DB_CHECK_CONT, 0);
}

int init_database_batch(sqlite3 *database, int rebuild, int init_type, const char *batch[])
{
    int rc;
    char *err_msg = NULL;
    for (int i = 0; batch[i]; i++) {
        debug(D_METADATALOG, "Executing %s", batch[i]);
        rc = sqlite3_exec_monitored(database, batch[i], 0, 0, &err_msg);
        if (rc != SQLITE_OK) {
            error_report("SQLite error during database %s, rc = %d (%s)", init_type ? "cleanup" : "setup", rc, err_msg);
            error_report("SQLite failed statement %s", batch[i]);
            sqlite3_free(err_msg);
            if (SQLITE_CORRUPT == rc) {
                if (!rebuild)
                    return attempt_database_fix();
                rc = check_table_integrity(NULL);
                if (rc)
                    error_report("Databse integrity errors reported");
            }
            return 1;
        }
    }
    return 0;
}

static void sqlite_uuid_parse(sqlite3_context *context, int argc, sqlite3_value **argv)
{
    uuid_t  uuid;

    if ( argc != 1 ){
        sqlite3_result_null(context);
        return ;
    }
    int rc = uuid_parse((const char *) sqlite3_value_text(argv[0]), uuid);
    if (rc == -1)  {
        sqlite3_result_null(context);
        return ;
    }

    sqlite3_result_blob(context, &uuid, sizeof(uuid_t), SQLITE_TRANSIENT);
}


/*
 * Initialize the SQLite database
 * Return 0 on success
 */
int sql_init_database(db_check_action_type_t rebuild, int memory)
{
    char *err_msg = NULL;
    char sqlite_database[FILENAME_MAX + 1];
    int rc;

    if (likely(!memory))
        snprintfz(sqlite_database, FILENAME_MAX, "%s/netdata-meta.db", netdata_configured_cache_dir);
    else
        strcpy(sqlite_database, ":memory:");

    rc = sqlite3_open(sqlite_database, &db_meta);
    if (rc != SQLITE_OK) {
        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;
    }

    if (rebuild & (DB_CHECK_INTEGRITY | DB_CHECK_FIX_DB)) {
        int errors_detected = 0;
        if (!(rebuild & DB_CHECK_CONT))
            info("Running database check on %s", sqlite_database);

        if (check_table_integrity("chart")) {
            errors_detected++;
            if (rebuild & DB_CHECK_FIX_DB)
                rebuild_chart();
            else
                error_report("Errors reported -- run with -W sqlite-fix");
        }

        if (check_table_integrity("dimension")) {
            errors_detected++;
            if (rebuild & DB_CHECK_FIX_DB)
                rebuild_dimension();
            else
                error_report("Errors reported -- run with -W sqlite-fix");
        }

        if (!errors_detected) {
            if (check_table_integrity(NULL))
                error_report("Errors reported");
        }
    }

    if (rebuild & DB_CHECK_RECLAIM_SPACE) {
        if (!(rebuild & DB_CHECK_CONT))
            info("Reclaiming space of %s", sqlite_database);
        rc = sqlite3_exec_monitored(db_meta, "VACUUM;", 0, 0, &err_msg);
        if (rc != SQLITE_OK) {
            error_report("Failed to execute VACUUM rc = %d (%s)", rc, err_msg);
            sqlite3_free(err_msg);
        }
    }

    if (rebuild && !(rebuild & DB_CHECK_CONT))
        return 1;

    info("SQLite database %s initialization", sqlite_database);

    char buf[1024 + 1] = "";
    const char *list[2] = { buf, NULL };

    int target_version = DB_METADATA_VERSION;

    if (likely(!memory))
        target_version = perform_database_migration(db_meta, DB_METADATA_VERSION);

    // https://www.sqlite.org/pragma.html#pragma_auto_vacuum
    // PRAGMA schema.auto_vacuum = 0 | NONE | 1 | FULL | 2 | INCREMENTAL;
    snprintfz(buf, 1024, "PRAGMA auto_vacuum=%s;", config_get(CONFIG_SECTION_SQLITE, "auto vacuum", "INCREMENTAL"));
    if(init_database_batch(db_meta, rebuild, 0, list)) return 1;

    // https://www.sqlite.org/pragma.html#pragma_synchronous
    // PRAGMA schema.synchronous = 0 | OFF | 1 | NORMAL | 2 | FULL | 3 | EXTRA;
    snprintfz(buf, 1024, "PRAGMA synchronous=%s;", config_get(CONFIG_SECTION_SQLITE, "synchronous", "NORMAL"));
    if(init_database_batch(db_meta, rebuild, 0, list)) return 1;

    // https://www.sqlite.org/pragma.html#pragma_journal_mode
    // PRAGMA schema.journal_mode = DELETE | TRUNCATE | PERSIST | MEMORY | WAL | OFF
    snprintfz(buf, 1024, "PRAGMA journal_mode=%s;", config_get(CONFIG_SECTION_SQLITE, "journal mode", "WAL"));
    if(init_database_batch(db_meta, rebuild, 0, list)) return 1;

    // https://www.sqlite.org/pragma.html#pragma_temp_store
    // PRAGMA temp_store = 0 | DEFAULT | 1 | FILE | 2 | MEMORY;
    snprintfz(buf, 1024, "PRAGMA temp_store=%s;", config_get(CONFIG_SECTION_SQLITE, "temp store", "MEMORY"));
    if(init_database_batch(db_meta, rebuild, 0, list)) return 1;

    // https://www.sqlite.org/pragma.html#pragma_journal_size_limit
    // PRAGMA schema.journal_size_limit = N ;
    snprintfz(buf, 1024, "PRAGMA journal_size_limit=%lld;", config_get_number(CONFIG_SECTION_SQLITE, "journal size limit", 16777216));
    if(init_database_batch(db_meta, rebuild, 0, list)) return 1;

    // https://www.sqlite.org/pragma.html#pragma_cache_size
    // PRAGMA schema.cache_size = pages;
    // PRAGMA schema.cache_size = -kibibytes;
    snprintfz(buf, 1024, "PRAGMA cache_size=%lld;", config_get_number(CONFIG_SECTION_SQLITE, "cache size", -2000));
    if(init_database_batch(db_meta, rebuild, 0, list)) return 1;

    snprintfz(buf, 1024, "PRAGMA user_version=%d;", target_version);
    if(init_database_batch(db_meta, rebuild, 0, list)) return 1;

    if (init_database_batch(db_meta, rebuild, 0, &database_config[0]))
        return 1;

    if (init_database_batch(db_meta, rebuild, 0, &database_cleanup[0]))
        return 1;

    info("SQLite database initialization completed");

    initialize_thread_key_pool();

    rc = sqlite3_create_function(db_meta, "u2h", 1, SQLITE_ANY | SQLITE_DETERMINISTIC, 0, sqlite_uuid_parse, 0, 0);
    if (unlikely(rc != SQLITE_OK))
        error_report("Failed to register internal u2h function");
    return 0;
}

/*
 * Close the sqlite database
 */

void sql_close_database(void)
{
    int rc;
    if (unlikely(!db_meta))
        return;

    info("Closing SQLite database");

    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, %s", rc, sqlite3_errstr(rc));
}

int exec_statement_with_uuid(const char *sql, uuid_t *uuid)
{
    int rc, result = 1;
    sqlite3_stmt *res = NULL;

    rc = sqlite3_prepare_v2(db_meta, sql, -1, &res, 0);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to prepare statement %s, rc = %d", sql, rc);
        return 1;
    }

    rc = sqlite3_bind_blob(res, 1, uuid, sizeof(*uuid), SQLITE_STATIC);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind host parameter to %s, rc = %d", sql, rc);
        goto skip;
    }

    rc = execute_insert(res);
    if (likely(rc == SQLITE_DONE))
        result = SQLITE_OK;
    else
        error_report("Failed to execute %s, rc = %d", sql, rc);

skip:
    rc = sqlite3_finalize(res);
    if (unlikely(rc != SQLITE_OK))
        error_report("Failed to finalize statement %s, rc = %d", sql, rc);
    return result;
}
// Return 0 OK
// Return 1 Failed
int db_execute(sqlite3 *db, const char *cmd)
{
    int rc;
    int cnt = 0;
    while (cnt < SQL_MAX_RETRY) {
        char *err_msg;
        rc = sqlite3_exec_monitored(db, cmd, 0, 0, &err_msg);
        if (rc != SQLITE_OK) {
            error_report("Failed to execute '%s', rc = %d (%s) -- attempt %d", cmd, rc, err_msg, cnt);
            sqlite3_free(err_msg);
            if (likely(rc == SQLITE_BUSY || rc == SQLITE_LOCKED)) {
                usleep(SQLITE_INSERT_DELAY * USEC_PER_MS);
            }
            else
                break;
        }
        else
            break;

        ++cnt;
    }
    return (rc != SQLITE_OK);
}

static inline void set_host_node_id(RRDHOST *host, uuid_t *node_id)
{
    if (unlikely(!host))
        return;

    if (unlikely(!node_id)) {
        freez(host->node_id);
        host->node_id = NULL;
        return;
    }

    struct aclk_sync_host_config *wc = host->aclk_sync_host_config;

    if (unlikely(!host->node_id))
        host->node_id = mallocz(sizeof(*host->node_id));
    uuid_copy(*(host->node_id), *node_id);

    if (unlikely(!wc))
        sql_create_aclk_table(host, &host->host_uuid, node_id);
    else
        uuid_unparse_lower(*node_id, wc->node_id);
}

#define SQL_UPDATE_NODE_ID  "update node_instance set node_id = @node_id where host_id = @host_id;"

int update_node_id(uuid_t *host_id, uuid_t *node_id)
{
    sqlite3_stmt *res = NULL;
    RRDHOST *host = NULL;
    int rc = 2;

    if (unlikely(!db_meta)) {
        if (default_rrd_memory_mode == RRD_MEMORY_MODE_DBENGINE)
            error_report("Database has not been initialized");
        return 1;
    }

    rc = sqlite3_prepare_v2(db_meta, SQL_UPDATE_NODE_ID, -1, &res, 0);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to prepare statement to store node instance information");
        return 1;
    }

    rc = sqlite3_bind_blob(res, 1, node_id, sizeof(*node_id), SQLITE_STATIC);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind host_id parameter to store node instance information");
        goto failed;
    }

    rc = sqlite3_bind_blob(res, 2, host_id, sizeof(*host_id), SQLITE_STATIC);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind host_id parameter to store node instance information");
        goto failed;
    }

    rc = execute_insert(res);
    if (unlikely(rc != SQLITE_DONE))
        error_report("Failed to store node instance information, rc = %d", rc);
    rc = sqlite3_changes(db_meta);

    char host_guid[GUID_LEN + 1];
    uuid_unparse_lower(*host_id, host_guid);
    rrd_wrlock();
    host = rrdhost_find_by_guid(host_guid);
    if (likely(host))
        set_host_node_id(host, node_id);
    rrd_unlock();

failed:
    if (unlikely(sqlite3_finalize(res) != SQLITE_OK))
        error_report("Failed to finalize the prepared statement when storing node instance information");

    return rc - 1;
}

#define SQL_SELECT_HOST_BY_NODE_ID  "select host_id from node_instance where node_id = @node_id;"

int get_host_id(uuid_t *node_id, uuid_t *host_id)
{
    static __thread 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 1;
    }

    if (unlikely(!res)) {
        rc = prepare_statement(db_meta, SQL_SELECT_HOST_BY_NODE_ID, &res);
        if (unlikely(rc != SQLITE_OK)) {
            error_report("Failed to prepare statement to select node instance information for a node");
            return 1;
        }
    }

    rc = sqlite3_bind_blob(res, 1, node_id, sizeof(*node_id), SQLITE_STATIC);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind host_id parameter to select node instance information");
        goto failed;
    }

    rc = sqlite3_step_monitored(res);
    if (likely(rc == SQLITE_ROW && host_id))
        uuid_copy(*host_id, *((uuid_t *) sqlite3_column_blob(res, 0)));

failed:
    if (unlikely(sqlite3_reset(res) != SQLITE_OK))
        error_report("Failed to reset the prepared statement when selecting node instance information");

    return (rc == SQLITE_ROW) ? 0 : -1;
}

#define SQL_SELECT_NODE_ID  "SELECT node_id FROM node_instance WHERE host_id = @host_id AND node_id IS NOT NULL;"

int get_node_id(uuid_t *host_id, uuid_t *node_id)
{
    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 1;
    }

    rc = sqlite3_prepare_v2(db_meta, SQL_SELECT_NODE_ID, -1, &res, 0);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to prepare statement to select node instance information for a host");
        return 1;
    }

    rc = sqlite3_bind_blob(res, 1, host_id, sizeof(*host_id), SQLITE_STATIC);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind host_id parameter to select node instance information");
        goto failed;
    }

    rc = sqlite3_step_monitored(res);
    if (likely(rc == SQLITE_ROW && node_id))
        uuid_copy(*node_id, *((uuid_t *) sqlite3_column_blob(res, 0)));

failed:
    if (unlikely(sqlite3_finalize(res) != SQLITE_OK))
        error_report("Failed to finalize the prepared statement when selecting node instance information");

    return (rc == SQLITE_ROW) ? 0 : -1;
}

#define SQL_INVALIDATE_NODE_INSTANCES "UPDATE node_instance SET node_id = NULL WHERE EXISTS " \
    "(SELECT host_id FROM node_instance WHERE host_id = @host_id AND (@claim_id IS NULL OR claim_id <> @claim_id));"

void invalidate_node_instances(uuid_t *host_id, uuid_t *claim_id)
{
    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_INVALIDATE_NODE_INSTANCES, -1, &res, 0);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to prepare statement to invalidate node instance ids");
        return;
    }

    rc = sqlite3_bind_blob(res, 1, host_id, sizeof(*host_id), SQLITE_STATIC);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind host_id parameter to invalidate node instance information");
        goto failed;
    }

    if (claim_id)
        rc = sqlite3_bind_blob(res, 2, claim_id, sizeof(*claim_id), SQLITE_STATIC);
    else
        rc = sqlite3_bind_null(res, 2);

    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind claim_id parameter to invalidate node instance information");
        goto failed;
    }

    rc = execute_insert(res);
    if (unlikely(rc != SQLITE_DONE))
        error_report("Failed to invalidate node instance information, rc = %d", rc);

failed:
    if (unlikely(sqlite3_finalize(res) != SQLITE_OK))
        error_report("Failed to finalize the prepared statement when invalidating node instance information");
}

#define SQL_GET_NODE_INSTANCE_LIST "SELECT ni.node_id, ni.host_id, h.hostname " \
    "FROM node_instance ni, host h WHERE ni.host_id = h.host_id AND h.hops >=0;"

struct node_instance_list *get_node_list(void)
{
    struct node_instance_list *node_list = NULL;
    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 NULL;
    }

    rc = sqlite3_prepare_v2(db_meta, SQL_GET_NODE_INSTANCE_LIST, -1, &res, 0);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to prepare statement to get node instance information");
        return NULL;
    };

    int row = 0;
    char host_guid[37];
    while (sqlite3_step_monitored(res) == SQLITE_ROW)
        row++;

    if (sqlite3_reset(res) != SQLITE_OK) {
        error_report("Failed to reset the prepared statement while fetching node instance information");
        goto failed;
    }
    node_list = callocz(row + 1, sizeof(*node_list));
    int max_rows = row;
    row = 0;
    // TODO: Check to remove lock
    rrd_rdlock();
    while (sqlite3_step_monitored(res) == SQLITE_ROW) {
        if (sqlite3_column_bytes(res, 0) == sizeof(uuid_t))
            uuid_copy(node_list[row].node_id, *((uuid_t *)sqlite3_column_blob(res, 0)));
        if (sqlite3_column_bytes(res, 1) == sizeof(uuid_t)) {
            uuid_t *host_id = (uuid_t *)sqlite3_column_blob(res, 1);
            uuid_unparse_lower(*host_id, host_guid);
            RRDHOST *host = rrdhost_find_by_guid(host_guid);
            if (rrdhost_flag_check(host, RRDHOST_FLAG_PENDING_CONTEXT_LOAD)) {
                info("ACLK: 'host:%s' skipping get node list because context is initializing", rrdhost_hostname(host));
                continue;
            }
            uuid_copy(node_list[row].host_id, *host_id);
            node_list[row].queryable = 1;
            node_list[row].live = (host && (host == localhost || host->receiver
                                            || !(rrdhost_flag_check(host, RRDHOST_FLAG_ORPHAN)))) ? 1 : 0;
            node_list[row].hops = (host && host->system_info) ? host->system_info->hops :
                                  uuid_memcmp(host_id, &localhost->host_uuid) ? 1 : 0;
            node_list[row].hostname =
                sqlite3_column_bytes(res, 2) ? strdupz((char *)sqlite3_column_text(res, 2)) : NULL;
        }
        row++;
        if (row == max_rows)
            break;
    }
    rrd_unlock();

failed:
    if (unlikely(sqlite3_finalize(res) != SQLITE_OK))
        error_report("Failed to finalize the prepared statement when fetching node instance information");

    return node_list;
};

#define SQL_GET_HOST_NODE_ID "select node_id from node_instance where host_id = @host_id;"

void sql_load_node_id(RRDHOST *host)
{
    static __thread 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;
    }

    if (unlikely(!res)) {
        rc = prepare_statement(db_meta, SQL_GET_HOST_NODE_ID, &res);
        if (unlikely(rc != SQLITE_OK)) {
            error_report("Failed to prepare statement to fetch node id");
            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_id parameter to load node instance information");
        goto failed;
    }

    rc = sqlite3_step_monitored(res);
    if (likely(rc == SQLITE_ROW)) {
        if (likely(sqlite3_column_bytes(res, 0) == sizeof(uuid_t)))
            set_host_node_id(host, (uuid_t *)sqlite3_column_blob(res, 0));
        else
            set_host_node_id(host, NULL);
    }

failed:
    if (unlikely(sqlite3_reset(res) != SQLITE_OK))
        error_report("Failed to reset the prepared statement when loading node instance information");
};


#define SELECT_HOST_INFO "SELECT system_key, system_value FROM host_info WHERE host_id = @host_id;"

void sql_build_host_system_info(uuid_t *host_id, struct rrdhost_system_info *system_info)
{
    int rc;

    sqlite3_stmt *res = NULL;

    rc = sqlite3_prepare_v2(db_meta, SELECT_HOST_INFO, -1, &res, 0);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to prepare statement to read host information");
        return;
    }

    rc = sqlite3_bind_blob(res, 1, host_id, sizeof(*host_id), SQLITE_STATIC);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind host parameter host information");
        goto skip;
    }

    while (sqlite3_step_monitored(res) == SQLITE_ROW) {
        rrdhost_set_system_info_variable(system_info, (char *) sqlite3_column_text(res, 0),
                                         (char *) sqlite3_column_text(res, 1));
    }

skip:
    if (unlikely(sqlite3_finalize(res) != SQLITE_OK))
        error_report("Failed to finalize the prepared statement when reading host information");
}

#define SELECT_HOST_LABELS "SELECT label_key, label_value, source_type FROM host_label WHERE host_id = @host_id " \
    "AND label_key IS NOT NULL AND label_value IS NOT NULL;"

DICTIONARY *sql_load_host_labels(uuid_t *host_id)
{
    int rc;

    DICTIONARY *labels = NULL;
    sqlite3_stmt *res = NULL;

    rc = sqlite3_prepare_v2(db_meta, SELECT_HOST_LABELS, -1, &res, 0);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to prepare statement to read host information");
        return NULL;
    }

    rc = sqlite3_bind_blob(res, 1, host_id, sizeof(*host_id), SQLITE_STATIC);
    if (unlikely(rc != SQLITE_OK)) {
        error_report("Failed to bind host parameter host information");
        goto skip;
    }

    labels = rrdlabels_create();

    while (sqlite3_step_monitored(res) == SQLITE_ROW) {
        rrdlabels_add(
            labels,
            (const char *)sqlite3_column_text(res, 0),
            (const char *)sqlite3_column_text(res, 1),
            sqlite3_column_int(res, 2));
    }

skip:
    if (unlikely(sqlite3_finalize(res) != SQLITE_OK))
        error_report("Failed to finalize the prepared statement when reading host information");
    return labels;
}

// Utils
int bind_text_null(sqlite3_stmt *res, int position, const char *text, bool can_be_null)
{
    if (likely(text))
        return sqlite3_bind_text(res, position, text, -1, SQLITE_STATIC);
    if (!can_be_null)
        return 1;
    return sqlite3_bind_null(res, position);
}

int sql_metadata_cache_stats(int op)
{
    int count, dummy;

    if (unlikely(!db_meta))
        return 0;

    netdata_thread_disable_cancelability();
    sqlite3_db_status(db_meta, op, &count, &dummy, 0);
    netdata_thread_enable_cancelability();
    return count;
}