db2 执行计划的解读 - myfriend2010的个人空间 - ITPUB个人空间 - powered by X-Space
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db2exfmt o Table Operators ITPUB个人空间TU3U&k5y0C@5_+A5O
db2exfmt TBSCAN - Table Scan ITPUB个人空间B)H u5D{Q,wi
db2exfmt IXSCAN - Index Scan
BaF M,hD#oB_0db2exfmt FETCH - Fetch from Table
d8etM2H*r~x.G9edq0db2exfmt ITPUB个人空间JT3] N/wz
db2exfmt o Joins
aeE-Y3w:R0db2exfmt MSJOIN - Merge Scan Join ITPUB个人空间ep3fsa;F
db2exfmt NLJOIN - Nested Loop Join ITPUB个人空间.c$P/t2o/U })i
db2exfmt HSJOIN - Hash Join
K(tjN?"h0db2exfmt
6k.DMbd/P0db2exfmt o Aggregation ITPUB个人空间:| F+j-P'l l8s,@7~Q
db2exfmt GRPBY - Group By ITPUB个人空间)H;G-G1L(W
db2exfmt SUM - Sum ITPUB个人空间5MO)c*y:~.}!rX
db2exfmt AVG - Average ITPUB个人空间.k%a }T,v'r|"ZP
db2exfmt MIN - Minimum ITPUB个人空间Uut#a1I
db2exfmt MAX - Maximun ITPUB个人空间Qw5\+oMM }
db2exfmt etc.
~ C'moOnJ0db2exfmt ITPUB个人空间 `)F5O(lO EDB
db2exfmt o Temp / Sort ITPUB个人空间8R\s{j'P8QD
db2exfmt TEMP - Insert into temp table ITPUB个人空间 a?vXk'~@+vS0H
db2exfmt SORT - Sort
:uxo&D n/sg/k }0db2exfmt ITPUB个人空间;TC2q8`)i'H5I|8]
db2exfmt o Special Operations
Q0[0V6n)e0db2exfmt IXAND - Index ANDing
3YE.R.V l B0db2exfmt RIDSCA - Index ORing or List Prefetch ITPUB个人空间*uGfjF5VO1X
db2exfmt IXA - Star Schema Bitmap Indexing ITPUB个人空间!vbB;{p z@;r)}
db2exfmt BTQ - Broadcast Table Queue
CG.T.@0NK9p0db2exfmt DTQ - Directed Table Queue ITPUB个人空间C Q }-f/`5F G_.d0x C!f
db2exfmt MBTQ - Merge Broadcast Table Queue ITPUB个人空间.I[/i&_R
db2exfmt MDTQ - Merge Directed Table Queue
#I nt*c&G0db2exfmt LTQ - Local Table Queue, for Intra-partition parallelism
+-------------------------------+-----------------------+-----------------------+ITPUB个人空间F[nJ2PMV
| Join Strategy | Inner Table | Outer Table |ITPUB个人空间PJ DV-fGO
+-------------------------------+-----------------------+-----------------------+ITPUB个人空间3^ V0T5h;Y&O(A#{f
| Collocated Join | Temporary Table | Temporary Table |
\9|"v*M _2vH'r0+-------------------------------+-----------------------+-----------------------+ITPUB个人空间 J,UpV;I:L0SJ9f
| Directed Inner Join | Temporary Table | Hashed Table Queue |
F2K"D F%O$X0| Directed Outer Join | Hashed Table Queue | Temporary Table |
V'R n \-}P_J,O;]&o0| Directed Inner and Outer Join | Hashed Table Queue | Hashed Table Queue |ITPUB个人空间c'X'o2}1Yj
+-------------------------------+-----------------------+-----------------------+
TK"_zI?l$pC1]0| Broadcast Inner Join | Temporary Table | Broadcast Table Queue |ITPUB个人空间[nbs#P'x9n
| Boradcast Outer Join | Broadcast Table Queue | Temporary Table |ITPUB个人空间x2vY2h~s,Z%_/iG
+-------------------------------+-----------------------+-----------------------+
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.
db2exfmt TBSCAN - Table Scan ITPUB个人空间B)H u5D{Q,wi
db2exfmt IXSCAN - Index Scan
BaF M,hD#oB_0db2exfmt FETCH - Fetch from Table
d8etM2H*r~x.G9edq0db2exfmt ITPUB个人空间JT3] N/wz
db2exfmt o Joins
aeE-Y3w:R0db2exfmt MSJOIN - Merge Scan Join ITPUB个人空间ep3fsa;F
db2exfmt NLJOIN - Nested Loop Join ITPUB个人空间.c$P/t2o/U })i
db2exfmt HSJOIN - Hash Join
K(tjN?"h0db2exfmt
6k.DMbd/P0db2exfmt o Aggregation ITPUB个人空间:| F+j-P'l l8s,@7~Q
db2exfmt GRPBY - Group By ITPUB个人空间)H;G-G1L(W
db2exfmt SUM - Sum ITPUB个人空间5MO)c*y:~.}!rX
db2exfmt AVG - Average ITPUB个人空间.k%a }T,v'r|"ZP
db2exfmt MIN - Minimum ITPUB个人空间Uut#a1I
db2exfmt MAX - Maximun ITPUB个人空间Qw5\+oMM }
db2exfmt etc.
~ C'moOnJ0db2exfmt ITPUB个人空间 `)F5O(lO EDB
db2exfmt o Temp / Sort ITPUB个人空间8R\s{j'P8QD
db2exfmt TEMP - Insert into temp table ITPUB个人空间 a?vXk'~@+vS0H
db2exfmt SORT - Sort
:uxo&D n/sg/k }0db2exfmt ITPUB个人空间;TC2q8`)i'H5I|8]
db2exfmt o Special Operations
Q0[0V6n)e0db2exfmt IXAND - Index ANDing
3YE.R.V l B0db2exfmt RIDSCA - Index ORing or List Prefetch ITPUB个人空间*uGfjF5VO1X
db2exfmt IXA - Star Schema Bitmap Indexing ITPUB个人空间!vbB;{p z@;r)}
db2exfmt BTQ - Broadcast Table Queue
CG.T.@0NK9p0db2exfmt DTQ - Directed Table Queue ITPUB个人空间C Q }-f/`5F G_.d0x C!f
db2exfmt MBTQ - Merge Broadcast Table Queue ITPUB个人空间.I[/i&_R
db2exfmt MDTQ - Merge Directed Table Queue
#I nt*c&G0db2exfmt LTQ - Local Table Queue, for Intra-partition parallelism
+-------------------------------+-----------------------+-----------------------+ITPUB个人空间F[nJ2PMV
| Join Strategy | Inner Table | Outer Table |ITPUB个人空间PJ DV-fGO
+-------------------------------+-----------------------+-----------------------+ITPUB个人空间3^ V0T5h;Y&O(A#{f
| Collocated Join | Temporary Table | Temporary Table |
\9|"v*M _2vH'r0+-------------------------------+-----------------------+-----------------------+ITPUB个人空间 J,UpV;I:L0SJ9f
| Directed Inner Join | Temporary Table | Hashed Table Queue |
F2K"D F%O$X0| Directed Outer Join | Hashed Table Queue | Temporary Table |
V'R n \-}P_J,O;]&o0| Directed Inner and Outer Join | Hashed Table Queue | Hashed Table Queue |ITPUB个人空间c'X'o2}1Yj
+-------------------------------+-----------------------+-----------------------+
TK"_zI?l$pC1]0| Broadcast Inner Join | Temporary Table | Broadcast Table Queue |ITPUB个人空间[nbs#P'x9n
| Boradcast Outer Join | Broadcast Table Queue | Temporary Table |ITPUB个人空间x2vY2h~s,Z%_/iG
+-------------------------------+-----------------------+-----------------------+
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.