Neoview Query Guide (R2.2)

Data TypeToken DescriptionToken
expr(text)Expression of the end key predicates on the indexindex_end_key
textCheck constraint on the delete tablecheck_constraint
Scan Operators
FILE_SCAN Operator
The FILE_SCAN operator contains details about how a certain access path is scanned, such as
lock_mode and scan_direction.
The FILE_SCAN operator has no child operators. The description field for this operator contains:
Data TypeToken DescriptionToken
integerA sequential number assigned to the fragment. 0 is always master executor
and 1 is reserved for the Explain plan. Numbers 2 to n will be ESP or DAM
fragments.
fragment_id
integerThe fragment_id for the parent fragment of the current fragment. Value is
(none) for master executor.
parent_frag
textmaster, ESP, or DAMfragment_type
textIndicates whether an optimization for short, simple operations is used. Value
is used if this optimization is used.
olt_optimization
textIndicates for short, simple operations whether a further optimization that
reduces the physical size of the plan is used.
olt_opt_lean
text{full scan | subset scan | unique access} of {index
index-name(table-name)| table}table-name
scan_type
text
Value volatile is present only if the scan is to a volatile table.
object_type
textDirection in which table is scanned: forward or reversescan_direction
text
Present if MDAM is used for the scan. Value used .
mdam
textThe lock mode specified: shared, exclusive, not specified, or unknownlock_mode
textThe access specified: read committed, read uncommitted, stable, skip conflict,
serializable, not specified, or unknown
access_mode
integerEstimate of the number of columns to be returnedcolumns_retrieved
textIndication of whether an optimization for a simple scan operation is used.
The value used is returned if this optimization is used.
fast_scan
textIndication of whether an optimization for returning data from DAM is used.
The value used is returned if this optimization is used.
fast_replydata_move
textPresent only if partition name is specified in the statement. Returns the name
of the partition.
partition_name
expr(text)Columns used as the primary keykey_columns
expr(text)Any predicate expression that is not a key predicate evaluated by the executor
in DAM
executor_predicates
expr(text)Disjunct key predicates used by MDAMmdam_disjunct
expr(text)Predicate expression specified on partitioning key. It is displayed only if
partitioning key differs from clustering key.
part_key_predicate
expr(text)Expression of the begin key predicatebegin_key
expr(text)Expression of the end key predicateend_key
Understanding Joins 53