db2 执行计划的解读

db2exfmt o Table Operators                                             ITPUB个人空间\.u0H*MJO:P.WO~!U
db2exfmt     TBSCAN - Table Scan
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N/A-F96990db2exfmt     IXSCAN - Index Scan                                       ITPUB个人空间jAMJ4L3n6\ H
db2exfmt     FETCH  - Fetch from Table
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h;Xb^k96990db2exfmt o Joins
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Fz8Z96990db2exfmt     MSJOIN - Merge Scan Join                                  ITPUB个人空间2F$[K+r3V7[#xp,bq"R
db2exfmt     NLJOIN - Nested Loop Join
&b(fhPKiW96990db2exfmt     HSJOIN - Hash Join
OS:^M1D bY)Ez(@+pF96990db2exfmt                                                               ITPUB个人空间Yc$k9S4Xv3? {w
db2exfmt o Aggregation                                                 ITPUB个人空间2M$k0T:T~.WVf7a-J
db2exfmt     GRPBY  - Group By
al(m4[$S2w w4{U96990db2exfmt     SUM    - Sum
IwD~^96990db2exfmt     AVG    - Average
6\6dl4csb96990db2exfmt     MIN    - Minimum
wMm(w]O96990db2exfmt     MAX    - Maximun
,z8Q\7}U3ddy96990db2exfmt     etc.
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zv ql`}F[)U96990db2exfmt o Temp / Sort
dbEfci6[-E96990db2exfmt     TEMP   - Insert into temp table                           ITPUB个人空间;q5K~s~)r1aw c-tD
db2exfmt     SORT   - Sort                                             ITPUB个人空间#eD6N#H,Nd
db2exfmt                                                               ITPUB个人空间 F7X:U'E:XA.bH u
db2exfmt o Special Operations
;}'M_ Wv-z(x.W4f96990db2exfmt     IXAND  - Index ANDing                                     ITPUB个人空间V T,U*fTW
db2exfmt     RIDSCA - Index ORing or List Prefetch
h*F kA i+J;e96990db2exfmt     IXA    - Star Schema Bitmap Indexing                      ITPUB个人空间,HzFjP
db2exfmt     BTQ    - Broadcast Table Queue
,f"SX8h2K E96990db2exfmt     DTQ    - Directed Table Queue
J.H}9[%a-S"E!|96990db2exfmt     MBTQ   - Merge Broadcast Table Queue
^o~/c!X96990db2exfmt     MDTQ   - Merge Directed Table Queue                       ITPUB个人空间`m:^ `b|
db2exfmt     LTQ    - Local Table Queue, for Intra-partition parallelism
+-------------------------------+-----------------------+-----------------------+ITPUB个人空间0s`t#K-G^*~-N
| Join Strategy                 | Inner Table           | Outer Table           |ITPUB个人空间X d,b,w {;eu
+-------------------------------+-----------------------+-----------------------+ITPUB个人空间A p,mbr
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| Collocated Join               | Temporary Table       | Temporary Table       |
;] ]S\p.S&r96990+-------------------------------+-----------------------+-----------------------+ITPUB个人空间+SA9N-`h{
| Directed Inner Join           | Temporary Table       | Hashed Table Queue    |ITPUB个人空间*S!@'n&C&YT i
| Directed Outer Join           | Hashed Table Queue    | Temporary Table       |ITPUB个人空间iqt
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| Directed Inner and Outer Join | Hashed Table Queue    | Hashed Table Queue    |
]3`$|,pp1kV~6TV96990+-------------------------------+-----------------------+-----------------------+
? t/NBIx96990| Broadcast Inner Join          | Temporary Table       | Broadcast Table Queue |
*s[J?/\[{A2A.y96990| Boradcast Outer Join          | Broadcast Table Queue | Temporary Table       |ITPUB个人空间Hr Ck^"^
+-------------------------------+-----------------------+-----------------------+
附:
BTQ   Broadcast Table Queue broadcasts data to several partitions.
DELETE   Deletes rows from a table.
DTQ   Directed Table Queue transfers data to a specific partition.
EISCAN   Scans a user-defined index to produce a reduced stream of rows.
FETCH   Fetches columns from a table using spe-cific record identifier.
FILTER   Represents the application of residual predicates.
GRPBY   Groups rows by common values of desig-nated columns or functions.
HSJOIN   Represents a hash join, where two or more tables are hashed on join columns.
INSERT   Inserts rows into a table.
IXAND   ANDs together the row identifiers (RIDs) from two or more index scans.
IXSCAN   Scans an index of a table with optional start/stop conditions, producing an ordered stream of rows.
LTQ   Local Table Queue. Transfers data between local agents.
LMTQ   Local Merge Table Queue. Merges data transferred between local agents.
MBTQ   Merging Broadcast Table Queue.
MDTQ   Merging Directed Table queue.
MSJOIN   Represents a merge join, where both outer and inner tables must be in join-predicate order.
NLJOIN   Represents a nested loop join that accesses an inner table once for each row of the outer table.
RETURN   Represents the return of data from the query to the user.
RIDSCAN   Scans a list of row identifiers (RIDs) obtained from one or more indexes.
RPD   For nonrelational wrappers, it shows the simulatedSQL operation that the nonrela-tional wrapper will be asked to perform.
SHIP   Retrieves data from a remote database source. Used in federated systems.
SORT   Sorts rows in the order of specified col-umns, and optionally eliminates duplicate entries.
TBSCAN   Retrieves rows by reading all required data directly from the data pages.
TEMP   Stores data in a temporary table to be read back out (possibly multiple times).
TQUEUE   Transfers table data between agents.
UNION   Concatenates streams of rows from multi-ple tables.
UNIQUE   Eliminates rows with duplicate values, for specified columns.
UPDATE   Updates rows in a table.