This library provides tools intended to be used at the interactive
toplevel for inspecting tables, table dependencies and table statistics.
- [nondet]table_statistics(?Stat,
-Value)
- [nondet]table_statistics(?Variant,
?Stat, -Value)
- Give summary statistics for the tables associated with all subgoals of Variant.
The table_statistics/2
version considers all tables.
The values for Stat are:
- tables
- Total number of answer tries
- answers
- Total number of answers in the combined tries
- duplicate_ratio
- Ratio of generated (and thus ignored) duplicate answers.
1 means no duplicates. 2 means for every
answer there was (on everage) a duplicate generated.
- space_ratio
- Number of nodes with a value divided by the total number of nodes in a
trie. The maximum is
1. A low number implies that a large
amount of differently shaped data is included in the answer tries.
- complete_call
- Number of times answers are generated from a completed table, i.e.,
times answers are reused.
- invalidated
- Number of times an incremental table was invalidated.
- reevaluated
- Number of times an invalidated table wa reevaluated. If lower than
invalidated
this implies that dependent nodes of the IDG were reevaluated to the
same answer set.
- space
- Summed memory usage of the answer tries in bytes.
- compiled_space
- Summed size for the compiled representation of completed tables.
- table_statistics
- Print a summary of statistics relevant to tabling.
- See also
- table_statistics/2
for an explanation
- table_statistics(:Variant)
- Print a summary for the statistics of all tables for subgoals of
Variant. See table_statistics/2
for an explanation.
- [det]table_statistics_by_predicate
- [det]table_statistics_by_predicate(+Options)
- Print statistics on memory usage and lookups per predicate. The version
without options dumps all predicates without ordering.
Options:
- order_by(+Key)
- Order the predicates according to Key. Default is
tables,
the number of answer tables. See table_statistics/2
for a list of values for Key.
- top(N)
- Only show the top N predicates.
- module(Module)
- Limit the results to predicates of the given module.
- tstat(?Value,
?Top)
- tstat(?Variant,
?Value, ?Top)
- Print the top-N (for positive Top) or bottom-N (for negative Top)
for Stat for all tabled subgoals of Variant (or
all tabled subgoals for tstat/2).
Stat is one of
- answers
- duplicate_ratio
- space_ratio
- gen(call)
- space
- compiled_space
- See table_statistics/2.
- deadlock
- Times this table was involved in a deadlock (cycle of threads waiting
for each others table to complete)
- wait
- Times a thread waited for this table.
- variables
- The number of variables in the variant. The tabling logic adds a term
ret(...)
to the table for each answer, where each variable is an argument of the ret(...)
term. The arguments are placed in depth-first lef-right order they
appear in the variant. Optimal behaviour of the trie is achieved if the
variance is as much as possible to the rightmost arguments. Poor
allocation shows up as a low space_ratio statistics.
Below are some examples
- [det]tdump
- [det]tdump(:Goal)
- [det]tdump(:Goal,
+Options)
- Dump all tables and their status that unify with Goal. Options:
- scope(Scope)
- Limit displayed tables to
local or global.
- limit(Count)
- Limit the number of answers displayed to Count
- reset(Boolean)
- If
true, also show reset (fresh) global tables. These are
tables that have been abolished.
- [det]tidg
- [det]tidg(:Goal)
- Dump the incremental dependency graph. idg/1
dumps the graph around a given node
- [det]summarize_idg
- [det]summarize_idg(+TopN)
- Implements XSB's
statistics(summarize_idg)