EXPLAIN_OPERATOR table
The EXPLAIN_OPERATOR table contains all the operators needed to satisfy the query statement by the query compiler.
| Column Name | Data Type | Nullable? | Key? | Description |
|---|---|---|---|---|
| EXPLAIN_REQUESTER | VARCHAR(128) | No | PK | Authorization ID of initiator of this Explain request. |
| EXPLAIN_TIME | TIMESTAMP | No | PK | Time of initiation for Explain request. |
| SOURCE_NAME | VARCHAR(128) | No | PK | Name of the package running when the dynamic statement was explained or name of the source file when the static SQL was explained. |
| SOURCE_SCHEMA | VARCHAR(128) | No | PK | Schema, or qualifier, of source of Explain request. |
| SOURCE_VERSION | VARCHAR(64) | No | PK | Version of the source of the Explain request. |
| EXPLAIN_LEVEL | CHAR(1) | No | PK | Level of Explain information for which this row is relevant. |
| STMTNO | INTEGER | No | PK | Statement number within package to which this explain information is related. |
| SECTNO | INTEGER | No | PK | Section number within package to which this explain information is related. |
| OPERATOR_ID | INTEGER | No | PK | Unique ID for this operator within this query. |
| OPERATOR_TYPE | CHAR(6) | No | No | Descriptive label for the type of operator. |
| TOTAL_COST | DOUBLE | No | No | Estimated cumulative total cost (in timerons) of executing the chosen access plan up to and including this operator. |
| IO_COST | DOUBLE | No | No | Estimated cumulative I/O cost (in data page I/Os) of executing the chosen access plan up to and including this operator. |
| CPU_COST | DOUBLE | No | No | Estimated cumulative CPU cost (in instructions) of executing the chosen access plan up to and including this operator. |
| FIRST_ROW_COST | DOUBLE | No | No | Estimated cumulative cost (in timerons) of fetching the first row for the access plan up to and including this operator. This value includes any initial overhead required. |
| RE_TOTAL_COST | DOUBLE | No | No | Estimated cumulative cost (in timerons) of fetching the next row for the chosen access plan up to and including this operator. |
| RE_IO_COST | DOUBLE | No | No | Estimated cumulative I/O cost (in data page I/Os) of fetching the next row for the chosen access plan up to and including this operator. |
| RE_CPU_COST | DOUBLE | No | No | Estimated cumulative CPU cost (in instructions) of fetching the next row for the chosen access plan up to and including this operator. |
| COMM_COST | DOUBLE | No | No | Estimated cumulative communication cost (in TCP/IP frames) of network traffic flowing across a single network adapter when executing the chosen access plan up to and including this operator. (See notes 1 and 2.) |
| FIRST_COMM_COST | DOUBLE | No | No | Estimated cumulative communications cost (in TCP/IP frames) of network traffic flowing across a single network adapter when fetching the first row for the chosen access plan up to and including this operator. This value includes any initial overhead required. (See notes 1 and 2.) |
| BUFFERS | DOUBLE | No | No | Estimated buffer requirements for this operator and its inputs. |
| REMOTE_TOTAL_COST | DOUBLE | No | No | Estimated cumulative total cost (in timerons) of performing operation(s) on remote database(s). |
| REMOTE_COMM_COST | DOUBLE | No | No | Estimated cumulative communication cost of executing the chosen remote access plan up to and including this operator. |
Note:
- If there is more than one network adapter involved, the cumulative communication cost for the adapter with the highest value is returned.
- This value only includes the costs of network traffic between physical machines. It does not include the virtual communication costs between node partitions on the same physical machine in a partitioned database environment.
| Value | Description |
|---|---|
| DELETE | Delete |
| EISCAN | Extended Index Scan |
| FETCH | Fetch |
| FILTER | Filter rows |
| GENROW | Generate Row |
| GRPBY | Group By |
| HSJOIN | Hash Join |
| INSERT | Insert |
| IXAND | Dynamic Bitmap Index ANDing |
| IXSCAN | Relational index scan |
| MSJOIN | Merge Scan Join |
| NLJOIN | Nested loop Join |
| REBAL | Rebalance rows between SMP subagents |
| RETURN | Result |
| RIDSCN | Row Identifier (RID) Scan |
| RPD | Remote PushDown |
| SHIP | Ship query to remote system |
| SORT | Sort |
| TBFUNC | In-stream table function operator |
| TBSCAN | Table Scan |
| TEMP | Temporary Table Construction |
| TQ | Table Queue |
| UNION | Union |
| UNIQUE | Duplicate Elimination |
| UPDATE | Update |
| XISCAN | Index scan over XML data |
| XSCAN | XML document navigation scan |
| XANDOR | Index ANDing and ORing over XML data |
| ZZJOIN | Zigzag join |