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a55602df4a
It is the case with the benchmark tool that we thought that we generated multiple series and saved them to the disk as such, when in reality, we overwrote the fields of the outgoing metrics via Go map reference behavior. This was accidental. In the course of diagnosing this, a few errors were found: 1. ``newSeriesFrontier`` should check to see if the candidate fingerprint is within the given domain of the ``diskFrontier``. If not, as the contract in the docstring stipulates, a ``nil`` ``seriesFrontier`` should be emitted. 2. In the interests of aiding debugging, the raw LevelDB ``levigoIterator`` type now includes a helpful forensics ``String()`` method. This work produced additional cleanups: 1. ``Close() error`` with the storage stack is technically incorrect, since nowhere in the bowels of it does an error actually occur. The interface has been simplified to remove this for now.
43 lines
1.7 KiB
Go
43 lines
1.7 KiB
Go
// Copyright 2013 Prometheus Team
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// Licensed under the Apache License, Version 2.0 (the "License");
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// you may not use this file except in compliance with the License.
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// You may obtain a copy of the License at
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//
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// http://www.apache.org/licenses/LICENSE-2.0
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//
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// Unless required by applicable law or agreed to in writing, software
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// distributed under the License is distributed on an "AS IS" BASIS,
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// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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// See the License for the specific language governing permissions and
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// limitations under the License.
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package leveldb
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// TODO: Evaluate whether to use coding.Encoder for the key and values instead
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// raw bytes for consistency reasons.
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// Iterator wraps Levigo and LevelDB's iterator behaviors in a manner that is
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// conducive to IO-free testing.
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//
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// It borrows some of the operational assumptions from goskiplist, which
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// functions very similarly, in that it uses no separate Valid method to
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// determine health. All methods that have a return signature of (ok bool)
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// assume in the real LevelDB case that if ok == false that the iterator
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// must be disposed of at this given instance and recreated if future
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// work is desired. This is a quirk of LevelDB itself!
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type Iterator interface {
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// GetError reports low-level errors, if available. This should not indicate
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// that the iterator is necessarily unhealthy but maybe that the underlying
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// table is corrupted itself. See the notes above for (ok bool) return
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// signatures to determine iterator health.
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GetError() error
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Key() []byte
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Next() (ok bool)
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Previous() (ok bool)
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Seek(key []byte) (ok bool)
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SeekToFirst() (ok bool)
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SeekToLast() (ok bool)
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Value() []byte
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Close()
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}
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