prometheus

Commit Graph

Author	SHA1	Message	Date
beorn7	8cdced3850	Implement Gorilla-inspired chunk encoding This is not a verbatim implementation of the Gorilla encoding. First of all, it could not, even if we wanted, because Prometheus has a different chunking model (constant size, not constant time). Second, this adds a number of changes that improve the encoding in general or at least for the specific use case of Prometheus (and are partially only possible in the context of Prometheus). See comments in the code for details.	9 years ago
beorn7	47e3c90f9b	Clean up error propagation Only return an error where callers are doing something with it except simply logging and ignoring. All the errors touched in this commit flag the storage as dirty anyway, and that fact is logged anyway. So most of what is being removed here is just log spam. As discussed earlier, the class of errors that flags the storage as dirty signals fundamental corruption, no even bubbling up a one-time warning to the user (e.g. about incomplete results) isn't helping much because _anything_ happening in the storage has to be doubted from that point on (and in fact retroactively into the past, too). Flagging the storage dirty, and alerting on it (plus marking the state in the web UI) is the only way I can see right now. As a byproduct, I cleaned up the setDirty method a bit and improved the logged errors.	9 years ago
beorn7	32f280a3cd	Slim down the chunkIterator interface For one, remove unneeded methods. Then, instead of using a channel for all values, use a bufio.Scanner-like interface. This removes the need for creating a goroutine and avoids the (unnecessary) locking performed by channel sending and receiving. This will make it much easier to write new chunk implementations (like Gorilla-style encoding).	9 years ago
beorn7	0ea5801e47	Handle errors caused by data corruption more gracefully This requires all the panic calls upon unexpected data to be converted into errors returned. This pollute the function signatures quite lot. Well, this is Go... The ideas behind this are the following: - panic only if it's a programming error. Data corruptions happen, and they are not programming errors. - If we detect a data corruption, we "quarantine" the series, essentially removing it from the database and putting its data into a separate directory for forensics. - Failure during writing to a series file is not considered corruption automatically. It will call setDirty, though, so that a crashrecovery upon the next restart will commence and check for that. - Series quarantining and setDirty calls are logged and counted in metrics, but are hidden from the user of the interfaces in interface.go, whith the notable exception of Append(). The reasoning is that we treat corruption by removing the corrupted series, i.e. a query for it will return no results on its next call anyway, so return no results right now. In the case of Append(), we want to tell the user that no data has been appended, though. Minor side effects: - Now consistently using filepath.* instead of path.*. - Introduced structured logging where I touched it. This makes things less consistent, but a complete change to structured logging would be out of scope for this PR.	9 years ago
beorn7	28e9bbc15f	Populate chunkDesc.chunkLastTime during checkpoint loading, too	9 years ago
beorn7	4221c7de5c	Improve handling of series file truncation If only very few chunks are to be truncated from a very large series file, the rewrite of the file is a lorge overhead. With this change, a certain ratio of the file has to be dropped to make it happen. While only causing disk overhead at about the same ratio (by default 10%), it will cut down I/O by a lot in above scenario.	9 years ago
Fabian Reinartz	1535ef1457	Replace metric.SamplePair with model.SamplePair	9 years ago
Fabian Reinartz	c9d396f476	Replace metric.LabelPair with model.LabelPair	9 years ago
Fabian Reinartz	306e8468a0	Switch from client_golang/model to common/model	9 years ago
beorn7	699946bf32	Fix chunk desc loading. If all samples in consecutive chunks have the same timestamp, the way we used to load chunks will fail. With this change, the persist watermark is used to load the right amount of chunkDescs from disk. This bug is a possible reason for the rare storage corruption we have observed.	10 years ago
beorn7	ff08f0b6fe	storage: ensure timestamp monotonicity within series. Fixes https://github.com/prometheus/prometheus/issues/481 While doing so, clean up and fix a few other things: - Fix `go vet` warnings (@fabxc to blame ;). - Fix a racey problem with unarchiving: Whenever we unarchive a series, we essentially want to do something with it. However, until we have done something with it, it appears like a series that is ready to be archived or even purged. So e.g. it would be ignored during checkpointing. With this fix, we always load the chunkDescs upon unarchiving. This is wasteful if we only want to add a new sample to an archived time series, but the (presumably more common) case where we access an archived time series in a query doesn't become more expensive. - The change above streamlined the getOrCreateSeries ond newMemorySeries flow. Also, the modTime is now always set correctly. - Fix the leveldb-backed implementation of KeyValueStore.Delete. It had the wrong behavior of still returning true, nil if a non-existing key has been passed in.	10 years ago
Fabian Reinartz	b105e26f4d	storage: remove global flags	10 years ago
Fabian Reinartz	0de6edbdfc	Move pkg/ to util/	10 years ago
Fabian Reinartz	3c8fbf1e15	Move test package to pkg/testutil	10 years ago
beorn7	3b9c421a69	Weed out all the [Gg]et* method names. The only exception is getNumChunksToPersist to avoid naming the struct member numChunksToPersist in a weird way.	10 years ago
beorn7	cd5574bf8a	Make chunk and series iterators more efficient.	10 years ago
Fabian Reinartz	d8440d75f1	Do not start storage processing before Start() is called.	10 years ago
beorn7	2235cec175	Handle fingerprint collisions.	10 years ago
beorn7	9820e5fe99	Use FastFingerprint where appropriate.	10 years ago
beorn7	66fc61f9b7	Make bufPool a member of the persistence struct.	10 years ago
beorn7	fbc44d8f95	Add benchmark for loading chunks and chunk descs.	10 years ago
beorn7	12ae6e9203	Increase resilience of the storage against data corruption - step 4. Step 4: Add a configurable sync'ing of series files after modification.	10 years ago
beorn7	e25cca823c	Increase resilience of the storage against data corruption - step 2. Step 2: Add a flag -storage.local.pedantic-checks to check every series file. Also, remove countPersistedHeadChunks channel, which is unused.	10 years ago
beorn7	0056eaeb4f	Redesign series maintenance and chunk persistence.	10 years ago
beorn7	5bea942d8e	Improve various things around chunk encoding. A number of mostly minor things: - Rename chunk type -> chunk encoding. - After all, do not carry around the chunk encoding to all parts of the system, but just have one place where the encoding for new chunks is set based on the flag. The new approach has caveats as well, but the polution of so many method signatures is worse. - Use the default chunk encoding for new chunks of existing series. (Previously, only new _series_ would get chunks with the default encoding.) - Use an enum for chunk encoding. (But keep the version number for the flag, for reasons discussed previously.) - Add encoding() to the chunk interface (so that a chunk knows its own encoding - no need to have that in a different top-level function). - Got rid of newFollowUpChunk (which would keep the existing encoding for all chunks of a time series). Now only use newChunk(), which will create a chunk encoding according to the flag. - Simplified transcodeAndAdd. - Reordered methods of deltaEncodedChunk and doubleDeltaEncoded chunk to match the order in the chunk interface. - Only transcode if the chunk is not yet half full. If more than half full, add a new chunk instead.	10 years ago
beorn7	a8d4f8af9a	Improve minor things after review. The problem of float precision will be addressed in the next commit.	10 years ago
beorn7	13fcf1ddbc	Implement double-delta encoded chunks.	10 years ago
beorn7	edd716e63c	Fix the embarrassing bug introduced in commit `0851945`. In that commit, the 'maintainSeries' call was accidentally removed. This commit refactors things a bit so that there is now a clean 'maintainMemorySeries' and a 'maintainArchivedSeries' call. Straighten the nomenclature a bit (consistently use 'drop' for chunks and 'purge' for series/metrics). Remove the annoying 'Completed maintenance sweep through archived fingerprints' message if there were no archived fingerprints to do maintenance on.	10 years ago
beorn7	af91fb8e31	Improve persisting chunks to disk. This is done by bucketing chunks by fingerprint. If the persisting to disk falls behind, more and more chunks are in the queue. As soon as there are "double hits", we will now persist both chunks in one go, doubling the disk throughput (assuming it is limited by disk seeks). Should even more pile up so that we end wit "triple hits", we will persist those first, and so on. Even if we have millions of time series, this will still help, assuming not all of them are growing with the same speed. Series that get many samples and/or are not very compressable will accumulate chunks faster, and they will soon get double- or triple-writes. To improve the chance of double writes, -storage.local.persistence-queue-capacity could be set to a higher value. However, that will slow down shutdown a lot (as the queue has to be worked through). So we leave it to the user to set it to a really high value. A more fundamental solution would be to checkpoint not only head chunks, but also chunks still in the persist queue. That would be quite complicated for a rather limited use-case (running many time series with high ingestion rate on slow spinning disks).	10 years ago
Bjoern Rabenstein	5859b74f1b	Clean up license issues. - Move CONTRIBUTORS.md to the more common AUTHORS. - Added the required NOTICE file. - Changed "Prometheus Team" to "The Prometheus Authors". - Reverted the erroneous changes to the Apache License.	10 years ago
Bjoern Rabenstein	7af42eda65	Optimize purging. Now only purge if there is something to purge. Also, set savedFirstTime and archived time range appropriately. (Which is needed for the optimization.) Change-Id: Idcd33319a84def3ce0318d886f10c6800369e7f9	10 years ago
Bjoern Rabenstein	904acd43da	Add crash recovery. Fix the behavior if preload for non-existent series is requested. Instead of returning an error (which triggers a panic further up), simply count those incidents. They can happen regularly, we just want to know if they happen too frequently because that would mean the indexing is behind or broken. Change-Id: I4b2d1b93c4146eeea897d188063cb9574a270f8b	10 years ago
Bjoern Rabenstein	5f8e9617ef	Add more tests. Add an end-to-end fuzz and race test. Fix a race exposed by the above. Change-Id: Ifaa39a90cefbde8d4c29bda197cc92592ded21bb	10 years ago
Bjoern Rabenstein	d215e013b7	Fix the weird chunkDesc shuffling bug. The root cause was that after chunkDesc eviction, the offset between memory representation of chunk layout (via chunkDescs in memory) was shiftet against chunks as layed out on disk. Keeping the offset up to date is by no means trivial, so this commit is pretty involved. Also, found a race that for some reason didn't bite us so far: Persisting chunks was completel unlocked, so if chunks were purged on disk at the same time, disaster would strike. However, locking the persisting of chunk revealed interesting dead locks. Basically, never queue under the fp lock. Change-Id: I1ea9e4e71024cabbc1f9601b28e74db0c5c55db8	10 years ago
Bjoern Rabenstein	096fa0f8b2	Squash a number of TODOs. - Staleness delta is no a proper function parameter and not replicated from package ast. - Named type 'chunks' replaced by explicit '[]chunk' to avoid confusion. - For the same reason, replaced 'chunkDescs' by '[]*chunkDescs'. - Verified that math.Modf is not a speed enhancement over conversion (actually 5x slower). - Renamed firstTimeField, lastTimeField into chunkFirstTime and chunkLastTime. - Verified unpin() is sufficiently goroutine-safe. - Decided not to update archivedFingerprintToTimeRange upon series truncation and added a rationale why. Change-Id: I863b8d785e5ad9f71eb63e229845eacf1bed8534	10 years ago
Bjoern Rabenstein	8fba3302bc	Bold changes to concurrency. (WIP. Probably doesn't work yet.) Change-Id: Id1537dfcca53831a1d428078a5863ece7bdf4875	10 years ago
Bjoern Rabenstein	0031a448e2	Add WaitForIndexing. Change-Id: I5a5c975c4246632f937413322c855bbe63d00802	10 years ago
Bjoern Rabenstein	c7aad110fb	Add an indexing queue and batch the ops. Some other improvements on the way, in particular codec -> codable renaming and addition of LookupSet methods. Change-Id: I978f8f3f84ca8e4d39a9d9f152ae0ad274bbf4e2	10 years ago
Bjoern Rabenstein	71206dbc06	More code cleanups. Add license text everywhere. And others.... Change-Id: I11ccde267a2ef7eb366c4788ba7aeae14ba7545c	10 years ago
Bjoern Rabenstein	f5f9f3514a	Major code cleanup. - Make it go-vet and golint clean. - Add comments, TODOs, etc. Change-Id: If1392d96f3d5b4cdde597b10c8dff1769fcfabe2	10 years ago
Bjoern Rabenstein	bbf49200ab	Implement methods in persistence.go. Change-Id: I804cdd0b30420e171825fd86fe1281eca0d5e638	10 years ago
Julius Volz	7e85711df0	Beginnings of a tiered index implementation. This reintroduces a LevelDB-based metrics index. Change-Id: I4111540301c52255a07b2f570761707a32f72c05	10 years ago
Bjoern Rabenstein	d742edfe0d	Fix precision loss. Large delta values often imply a difference between a large base value and the large delta value, potentially resulting in small numbers with a huge precision error. Since large delta values need 8 bytes anyway, we are not even saving memory. As a solution, always save the absoluto value rather than a delta once 8 bytes would be needed for the delta. Timestamps are then saved as 8 byte integers, while values are always saved as float64 in that case. Change-Id: I01100d600515e16df58ce508b50982ffd762cc49	10 years ago
Bjoern Rabenstein	52c9dc43a3	Improve testing. In particular, create a fuzz test for time series. Change-Id: I523a17912405a0b6b46bd395c781d201dfe55036	10 years ago
Julius Volz	3b25867d61	Add chunk persistence tests, fix storage tests. Change-Id: Id0b8f5382e99efa839cc0f826e92bbda985fe9a9	10 years ago
Bjoern Rabenstein	ecdf5ab14f	Index-persistence switched from gob to a hand-coded solution. Change-Id: Ib4ec42535bd08df16d34d4774bb638e35c5a1841	10 years ago
Julius Volz	e7ed39c9a6	Initial experimental snapshot of next-gen storage. Change-Id: Ifb8709960dbedd1d9f5efd88cdd359ee9fa9d26d	10 years ago

47 Commits (8ec10ae7a5c3ec7a0b6e54c326a09d9afc9d39e8)