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S. E. S#|SNAME |LCODE 25|CLAY |NJ5101 32|THAISZ|NJ5102 38|GOOD |FL6321 17|BAID |NY2091 57|BROWN |NY2092. SNAME |C# |GRADE. S#|C#|GR 32|8 |89 32|7 |91 25|7 |68 25|6 |76 32|6 |62. Result. S.S#=E.S# TRUE. S.S#=E.S# FALSE. S.S#=E.S# FALSE. S.S#=E.S# FALSE. S.S#=E.S# - PowerPoint PPT Presentation
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J1. NESTED LOOP
JOIN S on S.S#=E.S#
For each record in S, (the outer loop over records from the outer or driver relation),
retrieve every record from E, (the inner loops over the inner relation),
test join condition,
if it's true, concatenate the tuples (project off unwanted columns) and output,
else go to next E (inner-relation) record.SELECT SNAME,C#,GRADE FROM S=STUDENT,E=ENROLL WHERE S.S#=E.S#;
CODE GENERATION implements the operator, JOIN (equi-join, we will use for it.)
S#|C#|GR
32|8 |89
32|7 |91
25|7 |68
25|6 |76
32|6 |62
ES#|SNAME |LCODE
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
17|BAID |NY2091
57|BROWN |NY2092
S
S.S#=E.S#
FALSES.S#=E.S#FALSE
S.S#=E.S#TRUE
SNAME |C# |GRADE Result
CLAY | 7 | 68
S.S#=E.S#TRUE
CLAY | 6 | 76
S.S#=E.S#FALSE
Section 9 # 19
09_Queries_LECTURE2
J1. NESTED LOOP
Second inner loop pass:
SELECT SNAME,C#,GRADE FROM S=STUDENT,E=ENROLL WHERE S.S#=E.S#;
CODE GENERATION implements the operator, JOIN (equi-join, we will use for it.)
S#|C#|GR
32|8 |89
32|7 |91
25|7 |68
25|6 |76
32|6 |62
ES#|SNAME |LCODE
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
17|BAID |NY2091
57|BROWN |NY2092
S
S.S#=E.S
TRUES.S#=E.S#FALSE
S.S#=E.S#FALSE
SNAME |C# |GRADE res
CLAY | 7 | 68
S.S#=E.S#TRUE
CLAY | 6 | 76
THAISZ| 7 | 91 THAISZ| 6 | 62
S.S#=E.S
TRUETHAISZ| 8 | 89
Section 9 # 20
J1. NESTED LOOP
Third inner loop pass:
SELECT SNAME,C#,GRADE FROM S=STUDENT,E=ENROLL WHERE S.S#=E.S#;
CODE GENERATION implements the operator, JOIN (equi-join, we will use for it.)
S#|C#|GR
32|8 |89
32|7 |91
25|7 |68
25|6 |76
32|6 |62
ES#|SNAME |LCODE
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
17|BAID |NY2091
57|BROWN |NY2092
S
S.S#=E.S
FALSES.S#=E.S#FALSE
S.S#=E.S#FALSE
SNAME |C# |GRADE res
CLAY | 7 | 68 CLAY | 6 | 76
THAISZ| 7 | 91 THAISZ| 6 | 62
THAISZ| 8 | 89
S.S#=E.S
FALSE
S.S#=E.S
FALSE
Section 9 # 21
J1. NESTED LOOP
4th inner loop pass:
SELECT SNAME,C#,GRADE FROM S=STUDENT,E=ENROLL WHERE S.S#=E.S#;
CODE GENERATION implements the operator, JOIN (equi-join, we will use for it.)
S#|C#|GR
32|8 |89
32|7 |91
25|7 |68
25|6 |76
32|6 |62
ES#|SNAME |LCODE
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
17|BAID |NY2091
57|BROWN |NY2092
SSNAME |C# |GRADE res
CLAY | 7 | 68 CLAY | 6 | 76
THAISZ| 7 | 91 THAISZ| 6 | 62
THAISZ| 8 | 89
S.S#=E.S
FALSES.S#=E.S#FALSE
S.S#=E.S
FALSE
S.S#=E.S
FALSES.S#=E.S
FALSE
Section 9 # 9
J1. NESTED LOOP
R 5th and last inner loop pass:
SELECT SNAME,C#,GRADE FROM S=STUDENT,E=ENROLL WHERE S.S#=E.S#;
CODE GENERATION implements the operator, JOIN (equi-join, we will use for it.)
S#|C#|GR
32|8 |89
32|7 |91
25|7 |68
25|6 |76
32|6 |62
ES#|SNAME |LCODE
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
17|BAID |NY2091
57|BROWN |NY2092
SSNAME |C# |GRADE res
CLAY | 7 | 68 CLAY | 6 | 76
THAISZ| 7 | 91 THAISZ| 6 | 62
THAISZ| 8 | 89
S.S#=E.S
FALSE
S.S#=E.S#
FALSE
S.S#=E.S
FALSE
S.S#=E.S
FALSE
S.S#=E.S
FALSE
Section 9 # 23
J2. When there is an Index on one join attribute the join can be done in one pass (called Indexed Nested Loop.
If there is an index on E.S#, get r in S, get matching E-tuples using the index (need not scan entire inner relation, E, each time as was necessary with J1) .
R=SELECT SNAME,C#,GRADE FROM S=STUDENT,E=ENROLL WHERE S.S#=E.S#;
CODE GENERATION implements the operator, JOIN (equi-join, we will use for it.)
S#|SNAME |LCODE 25|CLAY |NJ510132|THAISZ|NJ510238|GOOD |FL632117|BAID |NY209157|BROWN |NY2092
RRN|S#|C#|GR 0 |32|8 |89 1 |32|7 |91 2 |25|7 |68 3 |25|6 |76 4 |32|6 |62
ES
RRN |S# 2,3 |250,1,4|32
Dense Index on E.S#
SNAME |C# |GRADE RCLAY | 7 | 68 CLAY | 6 | 76
THAISZ| 7 | 91 THAISZ| 6 | 62
THAISZ| 8 | 89
Section 9 # 24
J3. MERGE JOIN: If both S.S# and E.S# are clustered, then scan both S and E once in order, keeping in mind that S.S# is the primary key (uniqueness property), but E.S# is not.
R=SELECT SNAME,C#,GRADE FROM S=STUDENT,E=ENROLL WHERE S.S#=E.S#;
CODE GENERATION implements the operator, JOIN (equi-join, we will use for it.)
S#|SNAME |LCODE 17|BAID |NY209125|CLAY |NJ510132|THAISZ|NJ510238|GOOD |FL632157|BROWN |NY2092
S#|C#|GR 25|7 |68 25|6 |76 32|6 |6232|8 |89 32|7 |91
ESS.S#=E.S#
FALSE
SNAME |C# |GRADE R
S.S#=E.S#
TRUE
CLAY | 7 | 68 S.S#=E.S#
TRUE
CLAY | 6 | 76 S.S#=E.S#FALSE
S.S#=E.S#
TRUE
THAISZ| 6 | 62 S.S#=E.S#
TRUE
THAISZ| 8 | 89 S.S#=E.S#TRUETHAISZ| 7 | 91 S.S#=E.S#
FALSES.S#=E.S#
FALSE
J3'. SORT-MERGE JOIN: If R.A and S.B are not ordered, sort them first (into R' clustered on A and S' clustered on B), then apply MERGE (J2 above).
Section 9 # 25
J4. HASH-JOIN: RIDs hashed to buckets (pages). Corresponding buckets retrieved and scanned
GRACE JOIN: (first example of a hash-join technique): Allocate M pages of memory to the join process. Partition the M page frames as follows: One page frame for new pages as they are read from disk (called that page frame, IN), then the remaining B+1 become hash buckets R0,..,RB ( Note: B = M-2 ). Use hash function, h(S#)=MODB(S#)
Partial Sort (Build) Phase:
Partially-Sort-S: Read each S-page to IN, hash each record using h(S#) to R0,...,RB. If the bucket, say R i, is full (collision), flush it to temporary disk file named Si.
Partially-Sort-E: Read each E-page into IN, hash each record with h(S#). Upon collision in a bucket, say R j, flush its' contents to a temporary disk file, named Ej.
Probe Phase: With each pair of temporary files, S0 & E0, S1 & E2, S2 & E2, ... in turn, do as follows: Re-partition memory with two page frames called IN and OUT. With the rest, form one large hash area. For S i, construct an internal a hash table in the hash area using another hash function, k(S#) FOR E i, PROBE the hash table using k(S#) for matches, output the join of all matches to OUT.
CODE GENERATION implements the operator, JOIN
Section 9 # 26
2,0|25|6 |76|NY2091
J4. HASH-JOIN: RIDs hashed to buckets (pages). Matching buckets are retrieved and scanned.
R=SELECT SNAME,C#,GRADE FROM S=STUDENT,E=ENROLL WHERE S.S#=E.S#;
GRACE JOIN: (first example of a hash-join technique): Allocate M=4 pages of memory to the join process. Partition the M pages as follows: - One page for IN (putting new pages as they are read from disk), M-1=3 pages for buckets R 0,..,R2.
Build Phase.
Use hash function, h(S#)=MOD3(S#)
CODE GENERATION implements the operator, JOIN
SRID|S#|SNAME | LCODE1,0|17|BAID |NY2091
3,0|38|GOOD |FL6321
1,1|25|CLAY |NJ5101
2,0|32|THAISZ|NJ5102
2,1|57|BROWN |NY2092
ERID|S#|C#|GR| LCODE 1,0|17|5 |96|NJ5101
1,1|25|7 |68|ND4456
2,1|32|8 |89|NY2091
3,0|32|7 |91|FL6320
3,1|34|6 |62|ND4456
R0
R1
R2
IN
Partial-Sort-S:
Read each S-page to IN, hash
each record using h(S#) to R0,R1,R2.
Upon collision in any of the buckets,
flush to temporary disk file,
called S0,S1,S2.
S0
S1
S2
1,0|17|BAID |NY2091
1,1|25|CLAY |NJ5101
2,0|32|THAISZ|NJ5102
2,1|57|BROWN |NY2092
3,0|38|GOOD |FL6321
Collision! Dump R2 Then flush all.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
Do the same with E.E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
Section 9 # 27
CODE GENERATION implements the operator, GRACE JOIN
S0
S1
S2
Hash Phase: With each pair of temporary files, S0 & E0, S1 & E2, S2 & E2,... in turn, do as follows:
Re-partition memory into IN, OUT and one large hash area.
Probe Phase: For Si, BUILD internal a hash table in the hash area using another hash function, k(S#)=MOD4
(open addr for collisions)
FOR Ei, PROBE hash table using k for matches,
output join of matches to OUT.
Start with S0 and E0. But E0 empty (no output will be produced) so skip.
PROBE S1 and E1: 1. Read S1 page-1 to IN. 2. Hash IN to HASH.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
25|CLAY |NJ5101
25|CLAY |NJ5101
0
OUT
IN
123
Hash
Section 9 # 28
25|7 |68|ND4456
CODE GENERATION implements GRACE JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 page-1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
25|CLAY |NJ5101
CLAY|7 |68
25|6 |76|NY2091
CLAY|6 |76
0
OUT
IN
123
Hash
Section 9 # 29
CODE GENERATION implements GRACE JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT (Since OUT is full, flush OUT first.). But no match!8. Flush HASH and IN when done with S1, E1 Probe (before starting Probe S2, E2).
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
25|CLAY |NJ5101
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
34|6 |62|ND4456
Section 9 # 30
CODE GENERATION implements GRACE JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).
17|BAID |NY2091
32|THAISZ|NJ5102
Section 9 # 31
CODE GENERATION implements GRACE JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).3. Read S2 pg2 to IN 4. MOD3 hash IN to HASH (open addressing for collisions).
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
Section 9 # 32
CODE GENERATION implements GRACE JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).3. Read S2 pg2 to IN 4. MOD3 hash IN to HASH (open addressing for collisions).5.Read E2 to IN. 6.Hash to HASH. 7. If match, Concatenate to OUT...
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
17|5 |96|NJ5101 32|8 |89|NY2091
BAID |5|96
Section 9 # 33
CODE GENERATION implements GRACE JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).3. Read S2 pg2 to IN 4. MOD3 hash IN to HASH (open addressing for collisions).5.Read E2 to IN. 6.Hash to HASH. 7. If match, Concatenate to OUT...
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
32|8 |89|NY2091
BAID |5|96 THAISZ|8|89
Section 9 # 34
CODE GENERATION implements GRACE JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY |7|68
CLAY |6|76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).3. Read S2 pg2 to IN 4. MOD3 hash IN to HASH (open addressing for collisions).5.Read E2 to IN. 6.Hash to HASH. 7. If match, Concatenate to OUT...(repeat until E2 empty)8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
32|7 |91|FL6320
BAID |5|96 THAISZ|8|89
THAISZ|7|91
Section 9 # 35
J4. HASH-JOIN: (a better way than GRACE JOIN):
HYBRID HASH JOIN of SS#E (developed by former chair of NDSU CS Dept., Dr. L. Shapiro):
Partition the M pages of main memory allocated to the join process as follows: One page for the IN, 0ne page for the OUT, B pages for hash buckets, R1..RB, Leave the rest for a large internal hash table, R0.
PARTIAL SORT S: Read each S page to IN, hash each record using h(S#)=MODB(S#) to R0..RB. If a record hashes to R0, apply an internal hash function, k(S#) which hashes the record to a slot in R0. Use open addressing for k-collisions. When an h-collision occurs in any page R i i=1..B, flush that page to a disk file, called Si i=1..B.
PARTIALLY SORT E: Read each E page into IN, hash each record with h(S#) to R0..RB If record hashes to R0, apply internal hash function k(S#), and concatenate records that match to OUT. If a collision occurs in any page, Ri i=1..B, flush to temporary disk file, Ei i=1..B.
PROBE PHASE for pairs, Si and Ei i=1..B, do the same as in Grace Join.
Hybrid Hash Join can be done with Bit Filtering to eliminate non-participating tuples early and avoid wasted processing of non-participating tuples Much more detail and example walkthroughs can be found in the HTML version of these notes (also available from "Other Materials" http://www.cs.ndsu.nodak.edu/~perrizo/classes/765/09query.html
CODE GENERATION implements the operator, HYBRID HASH JOIN
Section 9 # 36
2,0|25|6 |76|NY2091
h=MOD3 k=MOD4 SELECT SNAME,C#,GRADE FROM S,E WHERE S.S#=E.S#;CODE GENERATION implements the operator, HYBRID HASH JOIN
SRID|S#|SNAME | LCODE1,0|17|BAID |NY2091
3,0|38|GOOD |FL6321
1,1|25|CLAY |NJ5101
2,0|32|THAISZ|NJ5102
2,1|57|BROWN |NY2092
ERID|S#|C#|GR| LCODE 1,0|17|5 |96|NJ5101
1,1|25|7 |68|ND4456
2,1|32|8 |89|NY2091
3,0|32|7 |91|FL6320
3,1|34|6 |62|ND4456
R1
R2
IN
Read each S-page to IN, hash each record using h(S#)=MOD3(S#) to R0,R1,R2. If h(S#)=0, k(S#) determines R0 slot (open addressing for collisions in R0). h collisions in R1, R2 flush to file, S1, S2 resp.
Similarly (note all h hashes goes to R1 or R2, So all E records flush to E1 and E2 and R0 is flushed too.
S0
S1
S2
1,0|17|BAID |NY2091
1,1|25|CLAY |NJ5101
2,0|32|THAISZ|NJ5102
2,1|57|BROWN |NY2092
3,0|38|GOOD |FL6321
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
57|BROWN |NY2092
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
R0
0123
OUT
Section 9 # 37
25|7 |68|ND4456
CODE GENERATION implements HYBRID JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 page-1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
25|CLAY |NJ5101
CLAY|7 |68
25|6 |76|NY2091
CLAY|6 |76
0
OUT
IN
123
Hash
Section 9 # 38
CODE GENERATION implements HYBRID JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT (Since OUT is full, flush OUT first.). But no match!8. Flush HASH and IN when done with S1, E1 Probe (before starting Probe S2, E2).
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
25|CLAY |NJ5101
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
34|6 |62|ND4456
Section 9 # 39
CODE GENERATION implements HYBRID JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).
17|BAID |NY2091
32|THAISZ|NJ5102
Section 9 # 40
CODE GENERATION implements HYBRID JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).3. Read S2 pg2 to IN 4. MOD3 hash IN to HASH (open addressing for collisions).
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
Section 9 # 41
CODE GENERATION implements HYBRID JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).3. Read S2 pg2 to IN 4. MOD3 hash IN to HASH (open addressing for collisions).5.Read E2 to IN. 6.Hash to HASH. 7. If match, Concatenate to OUT...
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
17|5 |96|NJ5101 32|8 |89|NY2091
BAID |5|96
Section 9 # 42
CODE GENERATION implements HYBRID JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY|7 |68
CLAY|6 |76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).3. Read S2 pg2 to IN 4. MOD3 hash IN to HASH (open addressing for collisions).5.Read E2 to IN. 6.Hash to HASH. 7. If match, Concatenate to OUT...
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
32|8 |89|NY2091
BAID |5|96 THAISZ|8|89
Section 9 # 43
CODE GENERATION implements HYBRID JOIN
S0
S1
S2
PROBE S1, E1: 1. Read S1 pg1 to IN. 2. Hash IN to HASH. 3. Read E1 to IN 4. Concatenate to OUT.5. Read (next page of) E1 to IN. 6. Hash to HASH. 7. If match, Concatenate to OUT... 8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
25|CLAY |NJ5101
32|THAISZ|NJ5102
38|GOOD |FL6321
E0
E1
E2
25|6 |76|NY2091
17|5 |96|NJ5101
25|7 |68|ND4456
32|8 |89|NY2091
32|7 |91|FL6320
34|6 |62|ND4456
CLAY |7|68
CLAY |6|76
0
OUT
IN
123
Hash
PROBE S2, E2: 1. Read S2 pg1 to IN 2. MOD3 hash IN to HASH (open addressing for collisions).3. Read S2 pg2 to IN 4. MOD3 hash IN to HASH (open addressing for collisions).5.Read E2 to IN. 6.Hash to HASH. 7. If match, Concatenate to OUT...(repeat until E2 empty)8. Flush HASH and IN when done Probing E1.
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
32|7 |91|FL6320
BAID |5|96 THAISZ|8|89
THAISZ|7|91
Section 9 # 44
2,0|32|THAISZ|NJ51021,0|17|BAID |NY2091
2,1|57|BROWN |NY20921,1|25|CLAY |NJ5101
3,0|38|GOOD |FL6321
2,0|25|6 |76|NY2091
h=MOD3 k=MOD4 SELECT SNAME,C#,GRADE FROM S,E WHERE S.S#=E.S#;
CODE generation of HYBRID HASH JOIN using R2 as internal hash bucket!
SRID|S#|SNAME | LCODE1,0|17|BAID |NY2091
3,0|38|GOOD |FL6321
1,1|25|CLAY |NJ5101
2,0|32|THAISZ|NJ5102
2,1|57|BROWN |NY2092
ERID|S#|C#|GR| LCODE 1,0|17|5 |96|NJ5101
1,1|25|7 |68|ND4456
2,1|32|8 |89|NY2091
3,0|32|7 |91|FL6320
3,1|34|6 |62|ND4456
IN
BUILD S: Read each S-page to IN, hash each record using h(S#)=MOD3(S#) to R0,R1,R2. If h(S#)=2, k(S#) determines R2 slot (open addressing for R2). h collisions in R1, R0 flush to file, S1, S0 resp.
S0
25|CLAY |NJ5101
57|BROWN |NY2092
E0R1
R0
R2
0123
OUT
E1
S1
Section 9 # 45
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
2,0|25|6 |76|NY2091
h=MOD3 k=MOD4 SELECT SNAME,C#,GRADE FROM S,E WHERE S.S#=E.S#; CODE generation implements HYBRID HASH JOIN using R2 as internal hash bucket!
SRID|S#|SNAME | LCODE1,0|17|BAID |NY2091
3,0|38|GOOD |FL6321
1,1|25|CLAY |NJ5101
2,0|32|THAISZ|NJ5102
2,1|57|BROWN |NY2092
ERID|S#|C#|GR| LCODE 1,0|17|5 |96|NJ5101
1,1|25|7 |68|ND4456
2,1|32|8 |89|NY2091
3,0|32|7 |91|FL6320
3,1|34|6 |62|ND4456
IN
BUILD E: Read first E-page to IN, hash each record using h(S#)=MOD3(S#) to R0,R1,R2. If h(S#)=2, k(S#) determines R2 slot (open addressing for R2). If match, concatenate to OUT. h collisions in R1, R0 flush to file, E1, E0 respectively.
S0
S1
S2
25|CLAY |NJ5101
57|BROWN |NY2092
E0R1
R0
R2
0123
OUT
E1
S1
1,0|17|5 |96|NJ5101
1,1|25|7 |68|ND4456
BAID |5 |96
Section 9 # 46
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
2,0|25|6 |76|NY2091
h=MOD3 k=MOD4 SELECT SNAME,C#,GRADE FROM S,E WHERE S.S#=E.S#;
SRID|S#|SNAME | LCODE1,0|17|BAID |NY2091
3,0|38|GOOD |FL6321
1,1|25|CLAY |NJ5101
2,0|32|THAISZ|NJ5102
2,1|57|BROWN |NY2092
ERID|S#|C#|GR| LCODE 1,0|17|5 |96|NJ5101
1,1|25|7 |68|ND4456
2,1|32|8 |89|NY2091
3,0|32|7 |91|FL6320
3,1|34|6 |62|ND4456
IN
BUILD E: Read second E-page to IN, hash each record using h(S#)=MOD3(S#) to R0,R1,R2. If h(S#)=2, k(S#) determines R2 slot (open addressing for R2). If match, concatenate to OUT. h collisions in R1, R0 flush to file, E1, E0 respectively.
S0
S1
S2
25|CLAY |NJ5101
57|BROWN |NY2092
E0R1
R0
R2
0123
OUT
E1
S1
25|7 |68|ND4456
BAID |5 |96
2,0|25|6 |76|NY2091
2,1|32|8 |89|NY2091
THAISZ|8 |89
CODE GEN implements HYBRID HASH JOIN using R2 as internal hash bucket!
Section 9 # 47
17|BAID |NY2091
32|THAISZ|NJ5102
38|GOOD |FL6321
2,0|25|6 |76|NY2091
h=MOD3 k=MOD4 SELECT SNAME,C#,GRADE FROM S,E WHERE S.S#=E.S#;
SRID|S#|SNAME | LCODE1,0|17|BAID |NY2091
3,0|38|GOOD |FL6321
1,1|25|CLAY |NJ5101
2,0|32|THAISZ|NJ5102
2,1|57|BROWN |NY2092
ERID|S#|C#|GR| LCODE 1,0|17|5 |96|NJ5101
1,1|25|7 |68|ND4456
2,1|32|8 |89|NY2091
3,0|32|7 |91|FL6320
3,1|34|6 |62|ND4456
IN
BUILD E: Read third E-page to IN, hash each record using h(S#)=MOD3(S#) to R0,R1,R2. If h(S#)=2, k(S#) determines R2 slot (open addressing for R2). If match, concatenate to OUT. h collisions in R1, R0 flush to file, E1, E0 respectively. When done building E, flush R2.
S0
S1
S2
25|CLAY |NJ5101
57|BROWN |NY2092
E0R1
R0
R2
0123
OUT
E1
S1
25|7 |68|ND4456
BAID |5 |96
25|6 |76|NY2091
THAISZ|8 |89
3,0|32|7 |91|FL6320
3,1|34|6 |62|ND4456
THAISZ|7 |91
25|7 |68|ND4456
25|6 |76|NY2091
34|6 |62|ND4456
CODE GEN implements HYBRID HASH JOIN using R2 as internal hash bucket!
Section 9 # 48
Note: If memory allocation is static, use all Ri pages for internal hash function! So k=MOD8
CODE GEN implements HYBRID HASH JOIN using R2 as internal hash bucket probe:
PROBE S:
S0
S1
S2
25|CLAY |NJ5101
57|BROWN |NY2092
E0
E1
S1
THAISZ|7 |91
25|7 |68|ND4456
25|6 |76|NY2091
34|6 |62|ND4456
IN
R2
0123
OUT
4567
25|CLAY |NJ5101
25|7 |68|ND4456
25|6 |76|NY2091
CLAY |7 |68
BAID |5 |96
THAISZ|8 |89
THAISZ|6 |76
h=MOD3 k=MOD4 SELECT SNAME,C#,GRADE FROM S,E WHERE S.S#=E.S#;
Notice how much more efficient the probe phase of HH JOIN is than Grace JOIN when the internal Hash table is chosen to apply to the right bucket!
(And how it may not be faster, if that decision is badly made!)
Section 9 # 49
![[XLS] y... · Web viewGRIFO MATILDE E.S PEGASO E.S SUPER REPSOL E.S TARAPACA GRIFO FLOR DE AMANCAES E.S SAN CRISTOBAL GRIFOS PERU SERVICENTRO PIZARRO GRIFO LOLESA ESTACION SOL DE](https://img.pdfslide.net/doc/110x75/5aaaeee27f8b9a81188ea491/xls-yweb-viewgrifo-matilde-es-pegaso-es-super-repsol-es-tarapaca-grifo-flor.jpg)
