When the db2exfmt utility formats explain tables, the output sometimes
contains symbols around operators.
The following tables list the various symbols that are
used with the operators of the ASCII explain graph.
Table 1. Symbols used with JOIN operator
| Character before operator |
Character after operator |
Equivalent Explain argument |
Argument value |
Description |
| > |
|
OUTERJN |
LEFT |
Left outer join |
| |
< |
OUTERJN |
RIGHT |
Right outer join |
| > |
< |
OUTERJN |
FULL |
Full outer join |
| x |
|
OUTERJN |
LEFT (ANTI) |
Left outer anti-join |
| |
x |
OUTERJN |
RIGHT (ANTI) |
Right outer anti-join |
| ^ |
|
EARLYOUT |
LEFT |
Left early out |
| |
^ |
EARLYOUT |
RIGHT |
Right early out |
Table 2. Symbols used with TQ operator
| Character before operator |
Character after operator |
Equivalent Explain argument |
Argument value |
Description |
| A |
|
TQORIGIN |
ASYNCHRONY |
Table queue that is used for asynchrony |
| B |
|
TQSEND |
BROADCAST |
All rows sent to all receiving database partitions |
| C |
|
TQORIGIN |
'COLUMN-ORGANIZED DATA' or 'ROW-ORGANIZED DATA' |
Represents
the transition between column-organized data
processing and row-organized data
processing |
| D |
|
TQSEND |
DIRECTED |
Rows are hashed to each of the receiving database
partitions by using the table queue 's partitioning key |
| L |
|
TQTYPE |
LOCAL |
Intra-partition parallelism |
| M |
|
TQMERGE |
TRUE |
Merging (sorted) table queue |
| X |
|
TQORIGIN |
XML AGG TQ |
Table queue that is used for XML aggregation |
| S |
|
TQSEND |
SCATTER |
Rows are scattered to receiving database partitions
without using a partitioning key |
| |
* |
LISTENER |
TRUE |
Table queue waits to receive values from other
database partitions |
Table 3. Unique symbols per key
| Character before operator |
Operator |
Equivalent Explain argument |
Argument value |
Description |
| p |
UNIQUE |
UNIQUE |
HASHED PARTIAL |
Partial early aggregation |
| p |
GRPBY |
AGGMODE |
HASHED PARTIAL |
Per group aggregation |
| g |
<many> |
GROUPS |
|
Multiple distinct processing |