The LevelDB stochastic tests could take a long time.
Original:
```
Matt:prometheus mtp$ make test
make -C model
protoc --go_out=generated/ data.proto
go build ./...
go test ./...
warning: building out-of-date packages:
github.com/matttproud/golang_instrumentation/maths
github.com/matttproud/golang_instrumentation/utility
github.com/matttproud/golang_instrumentation/metrics
github.com/matttproud/golang_instrumentation
installing these packages with 'go test -i ./...' will speed future tests.
? github.com/matttproud/prometheus [no test files]
? github.com/matttproud/prometheus/coding [no test files]
ok github.com/matttproud/prometheus/coding/indexable 0.012s
? github.com/matttproud/prometheus/model [no test files]
? github.com/matttproud/prometheus/model/generated [no test files]
? github.com/matttproud/prometheus/retrieval [no test files]
? github.com/matttproud/prometheus/storage/metric [no test files]
ok github.com/matttproud/prometheus/storage/metric/leveldb 70.800s
? github.com/matttproud/prometheus/storage/raw [no test files]
? github.com/matttproud/prometheus/storage/raw/index [no test files]
ok github.com/matttproud/prometheus/storage/raw/index/leveldb 0.012s
ok github.com/matttproud/prometheus/storage/raw/leveldb 0.016s
ok github.com/matttproud/prometheus/utility 0.012s
? github.com/matttproud/prometheus/utility/test [no test files]
```
to
```
Matt:prometheus mtp$ make test
make -C model
protoc --go_out=generated/ data.proto
go build ./...
go test ./...
warning: building out-of-date packages:
github.com/matttproud/golang_instrumentation/maths
github.com/matttproud/golang_instrumentation/utility
github.com/matttproud/golang_instrumentation/metrics
github.com/matttproud/golang_instrumentation
installing these packages with 'go test -i ./...' will speed future tests.
? github.com/matttproud/prometheus [no test files]
? github.com/matttproud/prometheus/coding [no test files]
ok github.com/matttproud/prometheus/coding/indexable 0.011s
? github.com/matttproud/prometheus/model [no test files]
? github.com/matttproud/prometheus/model/generated [no test files]
? github.com/matttproud/prometheus/retrieval [no test files]
? github.com/matttproud/prometheus/storage/metric [no test files]
ok github.com/matttproud/prometheus/storage/metric/leveldb 2.158s
? github.com/matttproud/prometheus/storage/raw [no test files]
? github.com/matttproud/prometheus/storage/raw/index [no test files]
ok github.com/matttproud/prometheus/storage/raw/index/leveldb 0.013s
ok github.com/matttproud/prometheus/storage/raw/leveldb 0.013s
ok github.com/matttproud/prometheus/utility 0.013s
? github.com/matttproud/prometheus/utility/test [no test files]
```
``TargetPool`` is a pool of targets pending scraping. For now, it
uses the ``heap.Interface`` from ``container/heap`` to provide a
priority queue for the system to scrape from the next target.
It is my supposition that we'll use a model whereby we create a
``TargetPool`` for each scrape interval, into which ``Target``
instances are registered.
Kill LevelDB watermarks due to redundancy.
General interface documentation has begun.
Creating custom types for the model to prevent errors down the
road.
Renaming of components for easier comprehension.
Exposition of interface in LevelDB.
Slew of simple refactorings.
