grails/hibernate: add pessimistic locking on using creteria -

i tried add pessimistic locking in creteria shown in doc http://grails.org/doc/latest/guide/gorm.html#locking had exception:

"error util.jdbcexceptionreporter - feature not supported: "for update && join"; sql statement: ... org.hibernate.exception.genericjdbcexception: not execute query"

i tried add lock in 2 places:

def parentinstance = parent.createcriteria().get {     childs {             ideq(childinstance.id)             lock true     } 

and

def parentinstance = parent.createcriteria().get {     childs {             ideq(childinstance.id)           }     lock true                } 

additional question: right way use pessimistic locking association?

thank you

domain

class parent{         static hasmany = [childs:child]     }  class child{  } 

datasource.groovy

        datasource {             pooled = true             driverclassname = "org.h2.driver"             username = "sa"             password = ""         }         hibernate {             cache.use_second_level_cache = true             cache.use_query_cache = false             cache.region.factory_class = 'net.sf.ehcache.hibernate.ehcacheregionfactory'         }         // environment specific settings         environments {             development {                 datasource {                     dbcreate = "update" // 1 of 'create', 'create-drop', 'update', 'validate', ''                     url = "jdbc:h2:myapp_proddb;mvcc=true"                 }             }             test {                 datasource {                     dbcreate = "update"                     url = "jdbc:h2:mem:myapp_testdb;mvcc=true"                 }             }             production {                 datasource {                     dbcreate = "update"                     url = "jdbc:h2:myapp_proddb;mvcc=true"                     pooled = true                     properties {                        maxactive = -1                        minevictableidletimemillis=1800000                        timebetweenevictionrunsmillis=1800000                        numtestsperevictionrun=3                        testonborrow=true                        testwhileidle=true                        testonreturn=true                        validationquery="select 1"                     }                 }             }         } 

depending on how form query, hibernate execute different queries. way query written hibernate perform join - can performance because means joined entities pre-fetched in 1 query. locking bad every joined table have locked , can have quite effect on deep hierarchies. database not allow (i'm not sure if other does).

you have perform query without joins. depending on domain class implementation simple child.parent.id done without touching database , query becomes simple parent.lock(child.parent.id). it's hard without seeing actual domain classes.

what can parent in non-locking query , call lock() method on returned instance. suggest take @ excellent article on locking things in gorm more information.