
PgQ trigger function `pgq.logutriga()` sends table change event into
queue in following format:

  ev_type::
    `(op || ":" || pkey_fields)`.  Where op is either "I", "U" or "D",
    corresponging to insert, update or delete.  And `pkey_fields`
    is comma-separated list of primary key fields for table.
    Operation type is always present but pkey_fields list can be empty,
    if table has no primary keys.  Example: `I:col1,col2`

  ev_data::
    Urlencoded record of data.  It uses db-specific urlecoding where
    existence of '=' is meaningful - missing '=' means NULL, present
    '=' means literal value.  Example: `id=3&name=str&nullvalue&emptyvalue=`

  ev_extra1::
    Fully qualified table name.

