history_str


CREATE TABLE lastvalue_str(
itemid bigint primary key,
clock integer NOT NULL DEFAULT 0,
value character varying(255) NOT NULL DEFAULT ''::character varying);

CREATE OR REPLACE FUNCTION lastvalue_str_func() RETURNS TRIGGER AS $BODY$
  DECLARE
  BEGIN
    IF (TG_OP = 'INSERT' OR TG_OP = 'UPDATE' ) THEN
       INSERT INTO lastvalue_str(itemid, clock, value)
       VALUES(NEW.itemid, NEW.clock, NEW.value)
       ON CONFLICT (itemid) DO
        UPDATE SET
          clock = NEW.clock, 
          value = NEW.value;
    END IF;
  RETURN NEW;
  END;
$BODY$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_insert_lastvalue_str
BEFORE INSERT OR UPDATE ON history_str
FOR EACH ROW EXECUTE 
PROCEDURE lastvalue_str_func();

CREATE OR REPLACE FUNCTION lastvalue_str_func_delete() RETURNS TRIGGER AS $BODY$
  DECLARE
  BEGIN
    IF (TG_OP = 'DELETE') THEN
       DELETE FROM lastvalue_str WHERE itemid = OLD.itemid;
    END IF;
  RETURN OLD;
  END;
$BODY$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_delete_lastvalue_str
BEFORE DELETE ON items 
FOR EACH ROW EXECUTE 
PROCEDURE lastvalue_str_func_delete();

**************************************************************************

history


CREATE TABLE lastvalue(
itemid bigint primary key,
clock integer NOT NULL DEFAULT 0,
value numeric(16,4) NOT NULL DEFAULT 0);

CREATE OR REPLACE FUNCTION lastvalue_func() RETURNS TRIGGER AS $BODY$
  DECLARE
  BEGIN
    IF (TG_OP = 'INSERT' OR TG_OP = 'UPDATE' ) THEN
       INSERT INTO lastvalue(itemid, clock, value)
       VALUES(NEW.itemid, NEW.clock, NEW.value)
       ON CONFLICT (itemid) DO
        UPDATE SET
          clock = NEW.clock, 
          value = NEW.value;
    END IF;
  RETURN NEW;
  END;
$BODY$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_insert_lastvalue
BEFORE INSERT OR UPDATE ON history
FOR EACH ROW EXECUTE 
PROCEDURE lastvalue_func();

CREATE OR REPLACE FUNCTION lastvalue_func_delete() RETURNS TRIGGER AS $BODY$
  DECLARE
  BEGIN
    IF (TG_OP = 'DELETE') THEN
       DELETE FROM lastvalue WHERE itemid = OLD.itemid;
    END IF;
  RETURN OLD;
  END;
$BODY$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_delete_lastvalue
BEFORE DELETE ON items 
FOR EACH ROW EXECUTE 
PROCEDURE lastvalue_func_delete();

**************************************************************************

history_text


CREATE TABLE lastvalue_text(
itemid bigint primary key,
clock integer NOT NULL DEFAULT 0,
value text NOT NULL DEFAULT ''::text);

CREATE OR REPLACE FUNCTION lastvalue_text_func() RETURNS TRIGGER AS $BODY$
  DECLARE
  BEGIN
    IF (TG_OP = 'INSERT' OR TG_OP = 'UPDATE' ) THEN
       INSERT INTO lastvalue_text(itemid, clock, value)
       VALUES(NEW.itemid, NEW.clock, NEW.value)
       ON CONFLICT (itemid) DO
        UPDATE SET
          clock = NEW.clock, 
          value = NEW.value;
    END IF;
  RETURN NEW;
  END;
$BODY$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_insert_lastvalue_text
BEFORE INSERT OR UPDATE ON history_text
FOR EACH ROW EXECUTE 
PROCEDURE lastvalue_text_func();

CREATE OR REPLACE FUNCTION lastvalue_text_func_delete() RETURNS TRIGGER AS $BODY$
  DECLARE
  BEGIN
    IF (TG_OP = 'DELETE') THEN
       DELETE FROM lastvalue_text WHERE itemid = OLD.itemid;
    END IF;
  RETURN OLD;
  END;
$BODY$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_delete_lastvalue_text
BEFORE DELETE ON items 
FOR EACH ROW EXECUTE 
PROCEDURE lastvalue_text_func_delete();

**************************************************************************

history_uint


CREATE TABLE lastvalue_uint(
itemid bigint primary key,
clock integer NOT NULL,
value numeric(20,0) NOT NULL);

CREATE OR REPLACE FUNCTION lastvalue_uint_func() RETURNS TRIGGER AS $BODY$
  DECLARE
  BEGIN
    IF (TG_OP = 'INSERT' OR TG_OP = 'UPDATE' ) THEN
       INSERT INTO lastvalue_uint(itemid, clock, value)
       VALUES(NEW.itemid, NEW.clock, NEW.value)
       ON CONFLICT (itemid) DO
        UPDATE SET
          clock = NEW.clock, 
          value = NEW.value;
    END IF;
  RETURN NEW;
  END;
$BODY$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_insert_lastvalue_uint
BEFORE INSERT OR UPDATE ON history_uint 
FOR EACH ROW EXECUTE 
PROCEDURE lastvalue_uint_func();

CREATE OR REPLACE FUNCTION lastvalue_uint_func_delete() RETURNS TRIGGER AS $BODY$
  DECLARE
  BEGIN
    IF (TG_OP = 'DELETE') THEN
       DELETE FROM lastvalue_uint WHERE itemid = OLD.itemid;
    END IF;
  RETURN OLD;
  END;
$BODY$ LANGUAGE plpgsql;

CREATE TRIGGER trigger_delete_lastvalue_uint
BEFORE DELETE ON items 
FOR EACH ROW EXECUTE 
PROCEDURE lastvalue_uint_func_delete();


**************************************************************************

Update permissions on the DB to zabbix and grafana_user (in case you are using Grafana to query directly the DB):

GRANT ALL PRIVILEGES ON ALL TABLES IN SCHEMA public TO zabbix;
GRANT USAGE ON SCHEMA public TO grafana_user;
GRANT SELECT ON all tables in schema public TO grafana_user;