Two postgres functions to retrieve param values from OpenNMS events.eventparms column. Tested on postgres 9.4

opennms_event_param_functions.sql

CREATE OR REPLACE FUNCTION event_pval_num(p_eventparams text, p_param text) RETURNS integer AS $$
        BEGIN
                RETURN (regexp_matches(p_eventparams,p_param||'=(\d+)'))[1];
        END;
$$ LANGUAGE plpgsql;

CREATE OR REPLACE FUNCTION event_pval_txt(p_eventparams text, p_param text) RETURNS text AS $$
        BEGIN
                RETURN (regexp_matches(p_eventparams,p_param||'=(.*?)\(string'))[1];
        END;
$$ LANGUAGE plpgsql;

-- example:
-- select event_pval_txt(eventparms,'nodelabel') from events where eventuei='uei.opennms.org/nodes/nodeUp';