With a very simple test, I get the 'mkey.bulk_rotate_xor_hash' exception. After this error, the only way I have found to recover is to drop the table, re-create and repopulate it. * System parameters: o MonetDB-11.3.1 o x86-64 ( note: build was missing a shared library that was subsequently ) o Solaris 10. o 96 GB memory * I create a simple table. create table fluid ( fluid bigint not null, userID int not null default 0, relativeUser bigint not null, typeID tinyint default 127, updateTime timestamp(0) default now(), constraint fluid_pk primary key( fluid, userID ), constraint user_fk1 foreign key ( userID ) references fuser ( userID ) ); create index rel_user_idx1 on fluid ( relativeUser ); create index userID_idx2 on fluid ( userID ); create index rel_user_user_idx1 on fluid ( relativeUser, userID ); create index update_idx1 on fluid ( updateTime ); * Populate it with records ( Note: the number of records does not seem to matter ). * Delete records. It does not appear to matter how many records I delete. Deleting 1 record or deleting all records seems to have the same effect. * Drop the primary key * Do "set optimizer='nov2009_pipe';" * Add the primary key. I always get the mkey.bulk_rotate_xor_hash exception. Here is a snapshot including a trace of a successful 'alter table drop constraint ...' command after NO records have been deleted. When I delete 1 ( or more records ), I get the exception with no trace output. sql>alter table fluid drop constraint fluid_pk; operation successful sql>set optimizer='nov2009_pipe'; sql>trace alter table fluid add constraint fluid_pk primary key( fluid, userID ); operation successful +------+--------------------------------------------------------------------------------------------------------------+ | tick | stmt | : s : : +======+==============================================================================================================+ | 7 | _2 := sql.mvc(); | | 451 | sql.catalog(29,"FLDB",42302696,0); | | 32 | _16:bat[:oid,:lng] [52] := sql.bind(_2=48362568,"FLDB","fluid","fluid",0); | | 22 | _13:bat[:oid,:int] [52] := sql.bind(_2=48362568,"FLDB","fluid","userID",0); | | 15 | _10:bat[:oid,:oid] [0] := sql.bind_dbat(_2=48362568,"FLDB","fluid",1); | | 10 | _12[0] := bat.reverse(_10=nil:bat[:oid,:oid]); | | 20 | _15[52] := algebra.kdifference(_13=nil:bat[:oid,:int],_12=[0]); | | 22 | _17[52] := algebra.kdifference(_16=nil:bat[:oid,:lng],_12=nil); | | 11 | _19:bat[:oid,:wrd] [52] := batcalc.hash(_17=[52]); | | 29 | _22[52] := bat.mirror(_17=[52]); | | 16 | _21:bat[:oid,:wrd] [52] := mkey.bulk_rotate_xor_hash(_19=nil:bat[:oid,:wrd],22,_15=[52]); : | 8 | _23[52] := bat.reverse(_22=nil); | | 52 | _24[52] := algebra.join(_23=nil,_21=nil:bat[:oid,:wrd]); | | 15 | (ext60[52],grp58[52]) := group.new(_24=[52]); | | 19 | (ext63[52],grp61[52]) := group.derive(ext60=nil,grp58=nil,_17=nil); | | 10 | (ext66[52],grp64[52]) := group.done(ext63=nil,grp61=nil,_15=nil); | | 9 | _31[52] := bat.mirror(ext66=nil); | | 10 | _32:bat[:oid,:wrd] [52] := aggr.count(grp64=nil,grp64=nil,_31=nil); | | 17 | return sum := aggr.sum(b=[52],true); | | 44 | _33:wrd := aggr.sum(_32=:bat[:oid,:wrd][52]); | | 5 | _34 := calc.isnil(_33=52:wrd); | | 7 | _37 := aggr.count(_32=nil:bat[:oid,:wrd]); | | 6 | _36 := calc.ifthenelse(_34=false,0:wrd,_33=52:wrd); | | 5 | _38 := calc.!=(_37=52:wrd,_36=52:wrd); | | 2827 | barrier _53 := language.dataflow(); | | 6 | sql.assert(_38=false,"UPDATE: PRIMARY KEY constraint 'fluid.fluid_pk' violated"); | | 27 | sql.update(_2=48362568,"FLDB","fluid","fluid_pk",_24=nil); | | 5 | sql.exportOperation(""); | | 3724 | user.s1_1(); | +------+--------------------------------------------------------------------------------------------------------------+ 29 tuples (50.262ms) sql>set optimizer='default_pipe'; sql>alter table fluid drop constraint fluid_pk; operation successful sql>delete from fluid where relativeUser = 11111; 1 affected row (1.557ms) sql>trace alter table fluid add constraint fluid_pk primary key( fluid, userID ); MALException:mkey.bulk_rotate_xor_hash:operation failed Operands not synced on head I need to periodically do bulk loads ( 'copy into' ), but also need to be able to periodically delete records from the same table. Is there a resolution to this problem? Thanks Steve