DB2 Materialised Query Table performance problems

I'm comparing performance on a series of tables involved in insert/updates/deletes.

These tables are about to become the source tables for a Materialised Query Table so I thought getting some statistics on the performance impact of the MQT would be a good idea.

Following like for like loads with and without the MQT I can see that there is a 18% performance hit due to the MQT.

Question is, is 18% a normal figure? Is it very high? I'm not sure as I have no basis for comparison. At the end of the day the business teams will make the final decision if it's acceptable however some feedback on whether this seems normal would be useful.

On the MQT I've put an index on each of the source table primary key columns that have to exist on the MQT, I wasn't sure if that was necessary but figured as the MQT needs the source tables Primary key in its definition then an index on those columns must make sense. I've also added some further indexes to improve queries etc.

Below is my MQT and indexes.

create table CRODSDBA.M_SEARCH_SYNC as (SELECT 
   CRODS.PARTY_GRP_ROLE.PARTY_GRP_ID,  
   CRODS.PARTY_GRP_ROLE.PARTY_LINK_ID,
   CRODS.PARTY_GRP_ROLE.PARTY_GRP_ROLE_ID,
   CRODS.PARTY_GRP_ROLE.VERSION PGRV,
   CRODS.NAME.NAME_ID,
   CRODS.NAME.VERSION NV,
   CRODS.NAME.SURNAME,           
   CRODS.NAME.FIRST_NAME,       
   CRODS.NAME.MIDDLE_NAME_1,      
   CRODS.NAME.MIDDLE_NAME_2,       
   CRODS.NAME.MIDDLE_NAME_3,
   CRODS.NAME.TITLE_CDE,             
   CRODS.NAME.DATE_OF_BIRTH,     
   CRODS.NAME.GENDER_CDE,
   CRODS.NAME.FLL_NM_SRCH_KEY_TX,
   CRODS.NAME.SURNM_SRCH_KEY_TX,              
   CRODS.NAME.CMPNY_NM_TYP_CDE, 

   CRODS.ADDRESS.ADDRESS_id,
   CRODS.ADDRESS.VERSION AV,
   CRODS.ADDRESS.ADDR_SEARCH_KEY_TX,  
   CRODS.ADDRESS.ADDRESS_FORMAT_CDE,
   CRODS.ADDRESS.STREET_NO,
   CRODS.ADDRESS.STREETNAME,
   CRODS.ADDRESS.STREET_TYPE,          
   CRODS.ADDRESS.STREET_DIRECTION,     
   CRODS.ADDRESS.SUBDWELLING_1_TYPE,   
   CRODS.ADDRESS.SUBDWELLING_1_NO,     
   CRODS.ADDRESS.SUBDWELLING_2_TYPE,   
   CRODS.ADDRESS.SUBDWELLING_2_NO,     
   CRODS.ADDRESS.POSTAL_TYPE,
   CRODS.ADDRESS.POSTAL_NO,      
   CRODS.ADDRESS.SUBURB,
   CRODS.ADDRESS.POSTCODE,
   CRODS.ADDRESS.STATE,
   CRODS.ADDRESS.COUNTRY_CDE,
   CRODS.ADDRESS.ADDRESS_DETAIL_1,
   CRODS.ADDRESS.ADDRESS_DETAIL_2,
   CRODS.ADDRESS.ADDRESS_DETAIL_3,

   CRODS.ADDRESS_XREF.ADDRESS_XREF_ID,
   CRODS.ADDRESS_XREF.VERSION AXV,
   CRODS.ADDRESS_XREF.ATTENTION,

   CRODS.PARTY.party_link_id next_plid,
   CRODS.PARTY.VERSION PV,
   CRODS.PARTY.SRC_SYS_NAME_CDE,
   CRODS.PARTY.SRC_SYS_PARTY_ID,
   CRODS.PARTY.LEGAL_ENTITY_CDE,
   CRODS.PARTY.PARTY_TYPE_CDE,

   CRODS.PARTY_GROUP.PARTY_GRP_ID PGPGID,
   CRODS.PARTY_GROUP.VERSION PGV,
   CRODS.PARTY_GROUP.PARTY_GRP_TYPE_CDE

FROM   CRODS.NAME,
   CRODS.ADDRESS_XREF,
   CRODS.ADDRESS,
   CRODS.PARTY,
   CRODS.PARTY_GRP_ROLE, 
   CRODS.PARTY_GROUP

WHERE  CRODS.ADDRESS_XREF.REF_TYPE_CDE    = 'PARTY'
   AND  CRODS.ADDRESS_XREF.VERSION         = 99999999
   AND  CRODS.ADDRESS_XREF.END_DATE        = DATE('9999-12-31')

   AND  CRODS.ADDRESS.ADDRESS_ID           = CRODS.ADDRESS_XREF.ADDRESS_ID 
   AND  CRODS.ADDRESS.VERSION              = 99999999
   AND  CRODS.ADDRESS.END_DATE             = DATE('9999-12-31')

   AND  CRODS.PARTY_GRP_ROLE.PARTY_LINK_ID = CRODS.ADDRESS_XREF.REF_ID
   AND  CRODS.PARTY_GRP_ROLE.VERSION       = 99999999
   AND  CRODS.PARTY_GRP_ROLE.END_DATE      = DATE('9999-12-31')

   AND  CRODS.PARTY_GRP_ROLE.PARTY_GRP_ID  = CRODS.PARTY_GROUP.PARTY_GRP_ID
   AND  CRODS.PARTY_GROUP.PARTY_GRP_ID    = CRODS.PARTY_GRP_ROLE.PARTY_GRP_ID
   AND  CRODS.PARTY_GRP_ROLE.PRIMARY_FLAG_CDE = 'Y'

   AND  CRODS.PARTY_GROUP.PARTY_GRP_TYPE_CDE IN ('CUSTOMER', 'USER', 'AGENT')
   AND  CRODS.PARTY_GROUP.VERSION = 99999999
   AND  CRODS.PARTY_GROUP.END_DATE = DATE('9999-12-31') 


   AND  CRODS.NAME.PARTY_LINK_ID           = CRODS.PARTY_GRP_ROLE.PARTY_LINK_ID 
   AND  CRODS.NAME.VERSION                 = 99999999
   AND  CRODS.NAME.END_DATE                = DATE('9999-12-31')

   AND  CRODS.PARTY.PARTY_LINK_ID          = CRODS.PARTY_GRP_ROLE.PARTY_LINK_ID
   AND  CRODS.PARTY.VERSION                = 99999999
   AND  CRODS.PARTY.END_DATE               = DATE('9999-12-31')
   AND  CRODS.PARTY.PARTY_STATUS_CDE       <>  'RESTRICTED'
   )
data initially deferred refresh immediate;

set integrity for CRODSDBA.M_SEARCH_SYNC immediate checked not incremental;

--BUILD THE INDEXES
DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_1;

CREATE  INDEX CRODSDBA.IDX_M_SEARCH_SYNC_1
    ON CRODSDBA.M_SEARCH_SYNC
    (PARTY_GRP_ROLE_ID      ASC,
      PGRV      DESC) PCTFREE 10
ALLOW REVERSE SCANS;

DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_2;

CREATE  INDEX CRODSDBA.IDX_M_SEARCH_SYNC_2
    ON CRODSDBA.M_SEARCH_SYNC
    (NAME_ID        ASC,
      NV        DESC) PCTFREE 10
ALLOW REVERSE SCANS;

DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_3;

CREATE INDEX CRODSDBA.IDX_M_SEARCH_SYNC_3   --PROCS USING: SEARCH_FULL_NAME_3_PERF, SEARCH_FULL_NAME_2_PERF, SEARCH_FULL_NAME_4_PERF, SEARCH_FULL_NAME_2_PERF
    ON CRODSDBA.M_SEARCH_SYNC
    (   FLL_NM_SRCH_KEY_TX      ASC,
        DATE_OF_BIRTH       ASC ,
        SUBURB      ASC,
        POSTCODE        ASC,
        LEGAL_ENTITY_CDE,   
        GENDER_CDE      ASC,        
        PARTY_GRP_TYPE_CDE ASC,
        PARTY_TYPE_CDE ASC


      )   CLUSTER   PCTFREE 10
ALLOW REVERSE SCANS;

DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_4;

CREATE INDEX CRODSDBA.IDX_M_SEARCH_SYNC_4  --PROCS USING: SEARCH_COMP_NAME_PERF.FILTER_EXACT
                    ON CRODSDBA.M_SEARCH_SYNC
                    (SURNAME        ASC,
                    POSTCODE,
                    PARTY_GRP_TYPE_CDE,
                    PARTY_TYPE_CDE
                    ) PCTFREE 10
                ALLOW REVERSE SCANS;

DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_5;

CREATE  INDEX CRODSDBA.IDX_M_SEARCH_SYNC_5
    ON CRODSDBA.M_SEARCH_SYNC
    (ADDRESS_ID     ASC,
      AV        DESC) PCTFREE 10
ALLOW REVERSE SCANS;

DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_6;

CREATE INDEX CRODSDBA.IDX_M_SEARCH_SYNC_6 --PROCS USING: SEARCH_COMP_NAME_PERF.FILTER_STD
                    ON CRODSDBA.M_SEARCH_SYNC
                    (DATE_OF_BIRTH ASC,
                    SURNM_SRCH_KEY_TX ASC,
                    SUBURB      ASC ,
                    POSTCODE        ASC , 
                    GENDER_CDE ASC,                     
                    PARTY_TYPE_CDE
                      )  PCTFREE 10
                ALLOW REVERSE SCANS;

DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_7;

CREATE INDEX CRODSDBA.IDX_M_SEARCH_SYNC_7
    ON CRODSDBA.M_SEARCH_SYNC
    (ADDRESS_XREF_ID        ASC,
      AXV       DESC) PCTFREE 10
ALLOW REVERSE SCANS;

DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_8;
CREATE  INDEX CRODSDBA.IDX_M_SEARCH_SYNC_8
    ON CRODSDBA.M_SEARCH_SYNC
    (next_plid  ASC,
      PV    DESC,
      LEGAL_ENTITY_CDE ASC, 
      PARTY_TYPE_CDE ASC)
   PCTFREE 10
ALLOW REVERSE SCANS;

DROP INDEX CRODSDBA.IDX_M_SEARCH_SYNC_9;
CREATE  INDEX CRODSDBA.IDX_M_SEARCH_SYNC_9
    ON CRODSDBA.M_SEARCH_SYNC
    (PARTY_GRP_ID       ASC,
      PGV       DESC
    )
   PCTFREE 10
ALLOW REVERSE SCANS;

--reorg table
reorg table crodsdba.M_SEARCH_SYNC;