Database MonetDB—为什么加倍自联接会导致同一数据上的查询执行时间从毫秒变为小时？
我正在相当简单的表上运行Database MonetDB—为什么加倍自联接会导致同一数据上的查询执行时间从毫秒变为小时？,database,performance,join,self-join,monetdb,Database,Performance,Join,Self Join,Monetdb,我正在相当简单的表上运行SQL查询。这些表使用引入的“垂直分区”对RDF图进行建模。因此，它们都有以下模型，s是“主体”，而o是客体 CREATE TABLE a_table (BIGINT s, BIGINT o) 假设我在表prop\u eventpreventinask中存储了449669元组。以下查询（表prop\u eventpreventinask上有4个自联接）在353 ms中运行 SELECT t1.s AS event1, t2.o AS event2, t3.o AS ev
SQLsoCREATE TABLE a_table (BIGINT s, BIGINT o)
prop\u eventpreventinask449669prop\u eventpreventinask353 ms中运行
SELECT t1.s AS event1, t2.o AS event2, t3.o AS event3,
t4.o AS event4, t5.o AS event5, t6.o AS event6
FROM "prop_SystemCallIsExecutedDuringTask" t1,
"prop_eventPrecedeInTask" t2,
"prop_eventPrecedeInTask" t3,
"prop_eventPrecedeInTask" t4,
"prop_eventPrecedeInTask" t5,
"prop_eventPrecedeInTask" t6
WHERE t1.o = 15667
AND t1.s = t2.s
AND t2.o = t3.s
AND t3.o = t4.s
AND t4.o = t5.s
AND t5.o = t6.s;
但是，当我将同一个表上的自连接数增加一倍（有9个自连接）时，查询在一小时后没有完成
SELECT t1.s AS event1, t2.o AS event2, t3.o AS event3,
t4.o AS event4, t5.o AS event5, t6.o AS event6,
t7.o AS event7, t8.o AS event8, t9.o AS event9,
t10.o AS event10, t11.o AS event11
FROM "prop_SystemCallIsExecutedDuringTask" t1,
"prop_eventPrecedeInTask" t2,
"prop_eventPrecedeInTask" t3,
"prop_eventPrecedeInTask" t4,
"prop_eventPrecedeInTask" t5,
"prop_eventPrecedeInTask" t6,
"prop_eventPrecedeInTask" t7,
"prop_eventPrecedeInTask" t8,
"prop_eventPrecedeInTask" t9,
"prop_eventPrecedeInTask" t10,
"prop_eventPrecedeInTask" t11
WHERE t1.o = 15667
AND t1.s = t2.s
AND t2.o = t3.s
AND t3.o = t4.s
AND t4.o = t5.s
AND t5.o = t6.s
AND t6.o = t7.s
AND t7.o = t8.s
AND t8.o = t9.s
AND t9.o = t10.s
AND t10.o = t11.s;
性能缺陷的解释是什么？我可以改进查询吗
配置
我正在使用64G内存机器上的MonetDB数据库服务器v1.7（2014年1月）Ubuntu12.0.4+-------+------------------------------------------------------------------------------------------------------------+
| ticks | stmt |
+=======+================================================================= ===========================================+
| 16 | X_3 := sql.mvc(); |
| 28 | X_7=<tmp_1326>[3939] := sql.bind(X_3=0,"sys","prop_SystemCallIsExecutedDuringTask","o",0); |
| 36 | (X_59=<tmp_21>[0],r1_129=<tmp_33>[0]) := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","s",2); |
| 20 | X_72=<tmp_33>[0] := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","o",1); |
| 13 | X_62=<tmp_33>[0] := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","s",1); |
| 30 | X_55:bat[:oid,:oid] =<tmp_17710>[78450] := sql.tid(X_3=0,"sys","prop_eventPrecedeInTask"); |
| 16 | X_37=<tmp_33>[0] := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","o",1); |
| 16 | (X_34=<tmp_21>[0],r1_40=<tmp_33>[0]) := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","o",2); |
| 14 | X_32=<tmp_2063>[78450] := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","o",0); |
| 15 | X_28=<tmp_33>[0] := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","s",1); |
| 13 | (X_26=<tmp_21>[0],r1_31=<tmp_33>[0]) := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","s",2); |
| 13 | X_25=<tmp_2055>[78450] := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","s",0); |
| 21 | X_23:bat[:oid,:oid] =<tmp_25746>[78450] := sql.tid(X_3=0,"sys","prop_eventPrecedeInTask"); |
| 30 | X_29=<tmp_33332>[78450] := sql.projectdelta(X_23=<tmp_25746>:bat[:oid,:oid][78450],X_25=<tmp_2055>[78450],
|
: : X_26=<tmp_21>[0],r1_31=<tmp_33>[0],X_28=<tmp_33>[0]); :
| 21 | (X_69=<tmp_21>[0],r1_140=<tmp_33>[0]) := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","o",2); |
| 21 | X_21=<tmp_33>[0] := sql.bind(X_3=0,"sys","prop_SystemCallIsExecutedDuringTask","s",1); |
| 14 | (X_19=<tmp_21>[0],r1_22=<tmp_33>[0]) := sql.bind(X_3=0,"sys","prop_SystemCallIsExecutedDuringTask","s",2); |
| 12 | X_17=<tmp_1320>[3939] := sql.bind(X_3=0,"sys","prop_SystemCallIsExecutedDuringTask","s",0); |
| 11 | X_13=<tmp_33>[0] := sql.bind(X_3=0,"sys","prop_SystemCallIsExecutedDuringTask","o",1); |
| 20 | (X_10=<tmp_21>[0],r1_10=<tmp_33>[0]) := sql.bind(X_3=0,"sys","prop_SystemCallIsExecutedDuringTask","o",2); |
| 24 | X_149=<tmp_34471>[0] := algebra.subselect(r1_10=<tmp_33> [0],A0=15667:lng,A0=15667:lng,true,true,false); |
| 18 | X_4:bat[:oid,:oid] =<tmp_4731>[3939] := sql.tid(X_3=0,"sys","prop_SystemCallIsExecutedDuringTask"); |
| 113 | X_148=<tmp_21746>[0] := algebra.subselect(X_7=<tmp_1326>[3939],X_4=<tmp_4731>:bat[:oid,:oid][3939],A0=1566 |
: : 7:lng,A0=15667:lng,true,true,false); :
| 24 | X_150=<tmp_6675>[0] := algebra.subselect(X_13=<tmp_33>[0],X_4=<tmp_4731>:bat[:oid,:oid][3939],A0=15667:lng |
: : ,A0=15667:lng,true,true,false); :
| 27 | X_38=<tmp_32620>[78450] := sql.projectdelta(X_23=<tmp_25746>:bat[:oid,:oid][78450],X_32=<tmp_2063>[78450], |
: : X_34=<tmp_21>[0],r1_40=<tmp_33>[0],X_37=<tmp_33>[0]); :
| 8 | language.pass(X_23=<tmp_25746>:bat[:oid,:oid][78450]); |
| 15 | X_56=<tmp_2055>[78450] := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","s",0); |
| 31 | X_65=<tmp_33344>[78450] := sql.projectdelta(X_55=<tmp_17710>:bat[:oid,:oid][78450],X_56=<tmp_2055>[78450], |
: : X_59=<tmp_21>[0],r1_129=<tmp_33>[0],X_62=<tmp_33>[0]); :
| 17 | X_68=<tmp_2063>[78450] := sql.bind(X_3=0,"sys","prop_eventPrecedeInTask","o",0); |
| 11 | X_15=<tmp_21746>[0] := sql.subdelta(X_148=<tmp_21746>[0],X_4=<tmp_4731>:bat[:oid,:oid][3939],X_10=<tmp_21> |
: : [0],X_149=<tmp_34471>[0],X_150=<tmp_6675>[0]); :
| 13 | language.pass(X_4=<tmp_4731>:bat[:oid,:oid][3939]); |
| 43 | X_22=<tmp_25746>[0] := sql.projectdelta(X_15=<tmp_21746>[0],X_17=<tmp_1320>[3939],X_19=<tmp_21>[0],r1_22=< |
: : tmp_33>[0],X_21=<tmp_33>[0]); :
| 33 | (X_30=<tmp_21746>[0],r1_36=<tmp_12754>[0]) := algebra.join(X_22=<tmp_25746>[0],X_29=<tmp_33332>[78450]); |
| 38 | X_39=<tmp_23566>[0] := algebra.leftfetchjoin(r1_36=<tmp_12754>[0],X_38=<tmp_32620>[78450]); |
| 28 | (X_40=<tmp_12754>[0],r1_58=<tmp_4661>[0]) := algebra.join(X_39=<tmp_23566>[0],X_29=<tmp_33332>[78450]); |
| 29 | X_42=<tmp_10412>[0] := algebra.leftfetchjoin(r1_58=<tmp_4661>[0],X_38=<tmp_32620>[78450]); |
| 18 | (X_43=<tmp_4661>[0],r1_76=<tmp_4056>[0]) := algebra.join(X_42=<tmp_10412>[0],X_29=<tmp_33332>[78450]); |
| 18 | X_45=<tmp_11601>[0] := algebra.leftfetchjoin(r1_76=<tmp_4056>[0],X_38=<tmp_32620>[78450]); |
| 14 | (X_46=<tmp_4056>[0],r1_97=<tmp_14043>[0]) := algebra.join(X_45=<tmp_11601>[0],X_29=<tmp_33332>[78450]); |
| 26 | X_73=<tmp_33524>[78450] := sql.projectdelta(X_55=<tmp_17710>:bat[:oid,:oid][78450],X_68=<tmp_2063>[78450], |
: : X_69=<tmp_21>[0],r1_140=<tmp_33>[0],X_72=<tmp_33>[0]); :
| 10 | language.pass(X_55=<tmp_17710>:bat[:oid,:oid][78450]); |
| 9434 | X_49=<tmp_13521>[0] := algebra.leftfetchjoin(r1_97=<tmp_14043>[0],X_38=<tmp_32620>[78450]); |
| 47 | (X_51=<tmp_14043>[0],r1_115=<tmp_36607>[0]) := algebra.join(X_49=<tmp_13521>[0],X_29=<tmp_33332>[78450]); |
| 6 | language.pass(X_29=<tmp_33332>[78450]); |
| 23 | X_54=<tmp_33332>[0] := algebra.leftfetchjoin(r1_115=<tmp_36607>[0],X_38=<tmp_32620>[78450]); |
| 7 | language.pass(X_38=<tmp_32620>[78450]); |
| 30 | (X_66=<tmp_4731>[0],r1_137=<tmp_6675>[0]) := algebra.join(X_54=<tmp_33332>[0],X_65=<tmp_33344>[78450]); |
| 19 | X_74=<tmp_34471>[0] := algebra.leftfetchjoin(r1_137=<tmp_6675>[0],X_73=<tmp_33524>[78450]); |
| 17 | (X_75=<tmp_6675>[0],r1_154=<tmp_4677>[0]) := algebra.join(X_74=<tmp_34471>[0],X_65=<tmp_33344>[78450]); |
| 14 | X_77=<tmp_11503>[0] := algebra.leftfetchjoin(r1_154=<tmp_4677>[0],X_73=<tmp_33524>[78450]); |
| 13 | (X_78=<tmp_4677>[0],r1_176=<tmp_6501>[0]) := algebra.join(X_77=<tmp_11503>[0],X_65=<tmp_33344>[78450]); |
| 15 | X_80=<tmp_24055>[0] := algebra.leftfetchjoin(r1_176=<tmp_6501>[0],X_73=<tmp_33524>[78450]); |
| 14 | (X_81=<tmp_6501>[0],r1_193=<tmp_7616>[0]) := algebra.join(X_80=<tmp_24055>[0],X_65=<tmp_33344>[78450]); |
| 16 | X_83=<tmp_25373>[0] := algebra.leftfetchjoin(r1_193=<tmp_7616>[0],X_73=<tmp_33524>[78450]); |
| 29 | (X_84=<tmp_7616>[0],r1_216=<tmp_7215>[0]) := algebra.join(X_83=<tmp_25373>[0],X_65=<tmp_33344>[78450]); |
| 7 | language.pass(X_65=<tmp_33344>[78450]); |
| 67 | X_98=<tmp_17710>[0] := algebra.leftfetchjoin(r1_216=<tmp_7215>[0],X_73=<tmp_33524>[78450]); |
| 2 | language.pass(X_73=<tmp_33524>[78450]); |
| 1129 | X_151=<tmp_26246>[0] := algebra.leftfetchjoin(X_84=<tmp_7616>[0],X_81=<tmp_6501>[0]); |
| 85 | X_86:bat[:oid,:lng] =<tmp_6501>[0] := algebra.leftfetchjoinPath(X_151=<tmp_26246>[0],X_78=<tmp_4677>[0],X_ |
: : 75=<tmp_6675>[0],X_66=<tmp_4731>[0],X_51=<tmp_14043>[0],X_46=<tmp_4056>[0],X_43=<tmp_4661>[0],X_40=<tmp_12 :
: : 754>[0],X_30=<tmp_21746>[0],X_22=<tmp_25746>[0]); :
| 67 | X_95=<tmp_32620>[0] := algebra.leftfetchjoin(X_84=<tmp_7616>[0],X_83=<tmp_25373>[0]); |
| 3 | language.pass(X_84=<tmp_7616>[0]); |
| 2 | language.pass(X_83=<tmp_25373>[0]); |
| 14 | X_89:bat[:oid,:lng] =<tmp_7616>[0] := algebra.leftfetchjoinPath(X_151=<tmp_26246>[0],X_78=<tmp_4677>[0],X_ |
: : 75=<tmp_6675>[0],X_66=<tmp_4731>[0],X_51=<tmp_14043>[0],X_46=<tmp_4056>[0],X_45=<tmp_11601>[0]); :
| 2 | language.pass(X_45=<tmp_11601>[0]); |
| 79 | X_87:bat[:oid,:lng] =<tmp_10432>[0] := algebra.leftfetchjoinPath(X_151=<tmp_26246>[0],X_78=<tmp_4677>[0],X |
: : _75=<tmp_6675>[0],X_66=<tmp_4731>[0],X_51=<tmp_14043>[0],X_46=<tmp_4056>[0],X_43=<tmp_4661>[0],X_40=<tmp_1 :
: : 2754>[0],X_39=<tmp_23566>[0]); :
| 2 | language.pass(X_40=<tmp_12754>[0]); |
| 7 | language.pass(X_22=<tmp_25746>[0]); |
| 6902 | X_88:bat[:oid,:lng] =<tmp_33524>[0] := algebra.leftfetchjoinPath(X_151=<tmp_26246>[0],X_78=<tmp_4677>[0],X |
: : _75=<tmp_6675>[0],X_66=<tmp_4731>[0],X_51=<tmp_14043>[0],X_46=<tmp_4056>[0],X_43=<tmp_4661>[0],X_42=<tmp_1 :
: : 0412>[0]); :
| 2 | language.pass(X_46=<tmp_4056>[0]); |
| 27091 | X_90:bat[:oid,:lng] =<tmp_11601>[0] := algebra.leftfetchjoinPath(X_151=<tmp_26246>[0],X_78=<tmp_4677>[0],X |
: : _75=<tmp_6675>[0],X_66=<tmp_4731>[0],X_51=<tmp_14043>[0],X_49=<tmp_13521>[0]); :
| 5 | language.pass(X_43=<tmp_4661>[0]); |
| 3 | language.pass(X_51=<tmp_14043>[0]); |
| 2 | language.pass(X_49=<tmp_13521>[0]); |
| 26 | X_91:bat[:oid,:lng] =<tmp_25746>[0] := algebra.leftfetchjoinPath(X_151=<tmp_26246>[0],X_78=<tmp_4677>[0],X |
: : _75=<tmp_6675>[0],X_66=<tmp_4731>[0],X_54=<tmp_33332>[0]); :
| 24 | X_92:bat[:oid,:lng] =<tmp_13521>[0] := algebra.leftfetchjoinPath(X_151=<tmp_26246>[0],X_78=<tmp_4677>[0],X |
: : _75=<tmp_6675>[0],X_74=<tmp_34471>[0]); :
| 2 | language.pass(X_75=<tmp_6675>[0]); |
| 1 | language.pass(X_54=<tmp_33332>[0]); |
| 10 | X_93:bat[:oid,:lng] =<tmp_6675>[0] := algebra.leftfetchjoinPath(X_151=<tmp_26246>[0],X_78=<tmp_4677>[0],X_ |
: : 77=<tmp_11503>[0]); :
| 1 | language.pass(X_78=<tmp_4677>[0]); |
| 1 | language.pass(X_74=<tmp_34471>[0]); |
| 7 | X_94:bat[:oid,:lng] =<tmp_34471>[0] := algebra.leftfetchjoin(X_151=<tmp_26246>[0],X_80=<tmp_24055>[0]); |
| 1 | language.pass(X_151=<tmp_26246>[0]); |
| 2 | language.pass(X_77=<tmp_11503>[0]); |
| 2 | language.pass(X_80=<tmp_24055>[0]); |
| 9 | language.pass(X_42=<tmp_10412>[0]); |
| 3 | language.pass(X_66=<tmp_4731>[0]); |
| 4 | language.pass(X_39=<tmp_23566>[0]); |
| 65664 | barrier X_178 := language.dataflow(); |
| 9 | X_99 := sql.resultSet(11,1,X_86=<tmp_6501>:bat[:oid,:lng][0]); |
| 6 | sql.rsColumn(X_99=4,"sys.L","event1","bigint",64,0,X_86=<tmp_6501>:bat[:oid,:lng][0]); |
| 4 | sql.rsColumn(X_99=4,"sys.L","event2","bigint",64,0,X_87=<tmp_10432>:bat[:oid,:lng][0]); |
| 4 | sql.rsColumn(X_99=4,"sys.L","event3","bigint",64,0,X_88=<tmp_33524>:bat[:oid,:lng][0]); |
| 3 | sql.rsColumn(X_99=4,"sys.L","event4","bigint",64,0,X_89=<tmp_7616>:bat[:oid,:lng][0]); |
| 3 | sql.rsColumn(X_99=4,"sys.L","event5","bigint",64,0,X_90=<tmp_11601>:bat[:oid,:lng][0]); |
| 3 | sql.rsColumn(X_99=4,"sys.L","event6","bigint",64,0,X_91=<tmp_25746>:bat[:oid,:lng][0]); |
| 2 | sql.rsColumn(X_99=4,"sys.L","event7","bigint",64,0,X_92=<tmp_13521>:bat[:oid,:lng][0]); |
| 3 | sql.rsColumn(X_99=4,"sys.L","event8","bigint",64,0,X_93=<tmp_6675>:bat[:oid,:lng][0]); |
| 5 | sql.rsColumn(X_99=4,"sys.L","event9","bigint",64,0,X_94=<tmp_34471>:bat[:oid,:lng][0]); |
| 5 | sql.rsColumn(X_99=4,"sys.L","event10","bigint",64,0,X_95=<tmp_32620>[0]); |
| 5 | sql.rsColumn(X_99=4,"sys.L","event11","bigint",64,0,X_98=<tmp_17710>[0]); |
| 2 | X_127 := io.stdout(); |
| 30 | sql.exportResult(X_127=="104d2":streams,X_99=4); |
| 1 | end s3_3; |
| 66047 | function user.s3_3(A0=15667:lng); |
| 66145 | X_5:void := user.s3_3(15667:lng); |
+-------+------------------------------------------------------------------------------------------------------------+
+-------+------------------------------------------------------------------------------------------------------------+
|滴答声| stmt|
+=======+================================================================= ===========================================+
|16 | X_3:=sql.mvc（）|
|28 | X_7=[3939]：=sql.bind（X_3=0，“sys”，“prop_systemcallisecutedduringtask”，“o”，0）|
|36 |（X_59=[0]，r1_129=[0]）：=sql.bind（X_3=0，“sys”，“prop_eventpreventintask”，“s”，2）|
|20 | X_72=[0]：=sql.bind（X_3=0，“sys”，“prop_eventpreventinask”，“o”，1）|
|13 | X_62=[0]：=sql.bind（X_3=0，“sys”，“prop_eventpreventinask”，“s”，1）|
|30|X_55:bat[：oid，：oid]=[78450]：=sql.tid（X_3=0，“sys”，“prop_eventpreventinask”）|
|16 | X_37=[0]：=sql.bind（X_3=0，“sys”，“prop_eventpreventinask”，“o”，1）|
|16 |（X_34=[0]，r1_40=[0]）：=sql.bind（X_3=0，“sys”，“prop_eventpreventintask”，“o”，2）|
|14 | X_32=[78450]：=sql.bind（X_3=0，“sys”，“prop_eventpreventinask”，“o”，0）|
|15 | X_28=[0]：=sql.bind（X_3=0，“sys”，“prop_eventpreventinask”，“s”，1）|
|13 |（X_26=[0]，r1_31=[0]）：=sql.bind（X_3=0，“sys”，“prop_eventpreventintask”，“s”，2）|
|13 | X_25=[78450]：=sql.bind（X_3=0，“sys”，“prop_eventpreventinask”，“s”，0）|
|21 | X|u 23:bat[：oid，：oid]=[78450]：=sql.tid（X|u 3=0，“sys”，“prop_eventpreventintask”）|
|30 | X_29=[78450]：=sql.projectdelta（X_23=:bat[:oid，:oid][78450]，X_25=[78450]，
|
：：X_26=[0]，r1_31=[0]，X_28=[0]）；：
|21 |（X_69=[0]，r1_140=[0]）：=sql.bind（X_3=0，“sys”，“prop_eventpreventintask”，“o”，2）|
|21 | X_21=[0]：=sql.bind（X_3=0，“sys”，“prop_systemcallisecutedduringtask”，“s”，1）|
|14 |（X_19=[0]，r1_22=[0]）：=sql.bind（X_3=0，“sys”，“prop_systemcallisecutedduringtask”，“s”，2）|
|12 | X_17=[3939]：=sql.bind（X_3=0，“sys”，“prop_systemcallisecutedduringtask”，“s”，0）|
|11 | X_13=[0]：=sql.bind（X_3=0，“sys”，“prop_systemcallisecutedduringtask”，“o”，1）|
|20 |（X_10=[0]，r1_10=[0]）：=sql.bind（X_3=0，“sys”，“prop_systemcallisecutedduringtask”，“o”，2）|
|24 | X_149=[0]：=代数。子选择（r1_10=[0]，A0=15667:lng，A0=15667:lng，真，真，假）|
|18 | X|u 4:bat[：oid，：oid]=[3939]：=sql.tid（X|u 3=0，“sys”，“prop_systemcallisecutedduringtask”）|
|113 | X_148=[0]：=代数。子选择（X_7=[3939]，X_4=:bat[：oid，：oid][3939]，A0=1566|
：7:lng，A0=15667:lng，真，真，假）；：
|24 | X_150=[0]：=代数。子选择（X_13=[0]，X_4=:bat[：oid，：oid][3939]，A0=15667:lng|
：，A0=15667:lng，对，对，错）
|27 | X_38=[78450]：=sql.projectdelta（X_23=:bat[:oid，:oid][78450]，X_32=[78450]|
：：X_34=[0]，r1_40=[0]，X_37=[0]）；：
|8 |语言。通过（X_23=：bat[：oid，：oid][78450]）|
|15 | X_56=[78450]：=sql.bind（X_3=0，“sys”，“prop_eventpreventinask”，“s”，0）|
|31 | X_65=[78450]：=sql.projectdelta（X_55=:bat[:oid，:oid][78450]，X_56=[78450]|
：：X_59=[0]，r1_129=[0]，X_62=[0]）；：
|17 | X_68=[78450]：=sql.bind（X_3=0，“sys”，“prop_eventpreventinask”，“o”，0）|
|11 | X_15=[0]：=sql.subdelta（X_148=[0]，X_4=:bat[：oid，：oid][3939]，X_10=|
：：[0]，X_149=[0]，X_150=[0]）；：
|13 |语言。通过（X_4=：bat[：oid，：oid][3939]）|
|43|X_22=[0]：=sql.projectdelta（X_15=[0]，X_17=[3939]，X_19=[0]，r1_22=<|
：：tmp_33>[0]，X_21=[0]）；：
|33 |（X_30=[0]，r1_36=[0]）：=代数。连接（X_22=[0]，X_29=[78450]）|
|38 | X_39=[0]：=代数。leftfetchjoin（r1_36=[0]，X_38=[78450]）|
|28 |（X_40=[0]，r1_58=[0]）：=代数.连接（X_39=[0]，X_29=[78450]）|
|29 | X_42=[0]：=代数。leftfetchjoin（r1_58=[0]，X_38=[78450]）|
|18 |（X_43=[0]，r1_76=[0]）：=代数.连接（X_42=[0]，X_29=[78450]）|
|18 | X_45=[0]：=代数。leftfetchjoin（r1_76=[0]，X_38=[78450]）；