Commit graph

117 commits

Author SHA1 Message Date
Jesus Vazquez e934d0f011 Merge 'main' into sparsehistogram
Signed-off-by: Jesus Vazquez <jesus.vazquez@grafana.com>
2022-10-05 22:14:49 +02:00
Giedrius Statkevičius a1d6ba59ac
promql: pass down subquery interval (#11163)
If we are populating series for a subquery then set the interval
parameter accordingly so that downstream users could use that
information.

Signed-off-by: Giedrius Statkevičius <giedrius.statkevicius@vinted.com>
2022-09-30 20:13:38 +05:30
beorn7 a7c519930e histograms: Add Compact method to the normal integer Histogram
And use the new method to call to compact Histograms during
parsing. This happens for both `Histogram` and `FloatHistogram`. In
this way, if targets decide to optimize the exposition size by merging
spans with empty buckets in between, we still get a normalized
results. It will also normalize away any valid but weird
representations like empty spans, spans with offset zero, and empty
buckets at the start or end of a span.

The implementation seemed easy at first as it just turns the
`compactBuckets` helper into a generic function (which now got its own
file). However, the integer Histograms have delta buckets instead of
absolute buckets, which had to be treated specially in the generic
`compactBuckets` function. To make sure it works, I have added plenty
of explicit tests for `Histogram` in addition to the `FloatHistogram`
tests.

I have also updated the doc comment for the `Compact` method.

Based on the insights now expressed in the doc comment, compacting
with a maxEmptyBuckets > 0 is rarely useful. Therefore, this commit
also sets the value to 0 in the two cases we were using 3 so far. We
might still want to reconsider, so I don't want to remove the
maxEmptyBuckets parameter right now.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-09-27 13:04:16 +02:00
Bryan Boreham b01d29cf9e promql: in tests use labels.FromStrings
And a few cases of `EmptyLabels()`.
Replacing code which assumes the internal structure of `Labels`.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2022-09-09 13:34:49 +02:00
Ganesh Vernekar 71489d0e3d
Fix count() for histograms and add test case
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-08-29 19:57:29 +05:30
Ganesh Vernekar 9325caa41c
Remove a TODO that is no longer valid (#11186)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2022-08-18 22:47:12 +05:30
beorn7 c9fd3c235d Merge branch 'main' into sparsehistogram 2022-08-10 17:54:37 +02:00
Vilius Pranckaitis 4660656312
Allow setting custom lookback delta for instant queries (#9946)
* Allow setting custom lookback delta for instant queries

Signed-off-by: Vilius Pranckaitis <vpranckaitis@gmail.com>
2022-08-02 11:15:39 +02:00
Levi Harrison 77a7af4461
Add histogram validation (#11052)
* Add histogram validation

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Correct negative offset validation

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Address review comments

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Validation benchmark

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Add more checks

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Attempt to fix tests

Signed-off-by: Levi Harrison <git@leviharrison.dev>

* Fix stuff

Signed-off-by: Levi Harrison <git@leviharrison.dev>
2022-07-29 09:52:49 -05:00
Łukasz Mierzwa 54a3c3ba3f
Print query that caused a panic (#10995)
We print the stacktrace of a panic when query causes one, but there's no
information about the query itself, which makes it harder to debug and
reproduce the issue.
This adds the 'expr' string to the logged panic.

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-07-14 15:04:15 +05:30
beorn7 9eafed0f79 promql: Add histogram_count and histogram_sum
This follow a simple function-based approach to access the count and
sum fields of a native Histogram. It might be more elegant to
implement “accessors” via the dot operator, as considered in the
brainstorming doc [1]. However, that would require the introduction of
a whole new concept in PromQL. For the PoC, we should be fine with the
function-based approch. Even the obvious inefficiencies (rate'ing a
whole histogram twice when we only want to rate each the count and the
sum once) could be optimized behind the scenes.

Note that the function-based approach elegantly solves the problem of
detecting counter resets in the sum of observations in the case of
negative observations. (Since the whole native Histogram is rate'd,
the counter reset is detected for the Histogram as a whole.)

We will decide later if an “accessor” approach is really needed. It
would change the example expression for average duration in
functions.md from

      histogram_sum(rate(http_request_duration_seconds[10m]))
	/
      histogram_count(rate(http_request_duration_seconds[10m]))

to

      rate(http_request_duration_seconds.sum[10m])
	/
      rate(http_request_duration_seconds.count[10m])

[1]: https://docs.google.com/document/d/1ch6ru8GKg03N02jRjYriurt-CZqUVY09evPg6yKTA1s/edit

Signed-off-by: beorn7 <beorn@grafana.com>
2022-06-28 18:16:48 +02:00
beorn7 a3a8f58bb3 promql: Add histogram_fraction function
Signed-off-by: beorn7 <beorn@grafana.com>
2022-06-28 15:58:03 +02:00
beorn7 ffaabea91a promql: Refine zero bucket treatment in histogramQuantile
Essentially, this mirrors the existing behavior for negative buckets:
If a histogram has only negative buckets, the upper bound of the zero
bucket is assumed to be zero.

Furthermore, it makes sure that the zero bucket boundaries are not
modified if a histogram that has no buckets at all but samples in the
zero bucket.

Also, add an TODO to vet if we really want this behavior.

Signed-off-by: beorn7 <beorn@grafana.com>
2022-06-19 15:06:51 +02:00
beorn7 40ad5e284a Merge branch 'main' into beorn7/sparsehistogram 2022-06-09 20:50:30 +02:00
Łukasz Mierzwa 08262454a3
Preallocate Labels in labels.Builder (#10749)
This tries to avoid re-allocations of labels slice since we know possible max size

Signed-off-by: Łukasz Mierzwa <l.mierzwa@gmail.com>
2022-05-25 16:22:47 +02:00
beorn7 3bc711e333 Merge branch 'main' into sparsehistogram 2022-05-04 13:37:13 +02:00
Matthieu MOREL e2ede285a2
refactor: move from io/ioutil to io and os packages (#10528)
* refactor: move from io/ioutil to io and os packages
* use fs.DirEntry instead of os.FileInfo after os.ReadDir

Signed-off-by: MOREL Matthieu <matthieu.morel@cnp.fr>
2022-04-27 11:24:36 +02:00
Alan Protasio ce6a643ee8
Changing TotalQueryableSamples from int to int64 (#10549)
* Changing TotalQueryableSamples from int to int64

Signed-off-by: Alan Protasio <approtas@amazon.com>
2022-04-12 01:22:25 +02:00
beorn7 4210aac74a Merge branch 'main' into sparsehistogram 2022-03-22 14:47:42 +01:00
Andrew Bloomgarden a64b9fe323 Report PeakSamples in query statistics
This exactly corresponds to the statistic compared against MaxSamples
during the course of query execution, so users can see how close their
queries are to a limit.

Co-authored-by: Harkishen Singh <harkishensingh@hotmail.com>
Co-authored-by: Andrew Bloomgarden <blmgrdn@amazon.com>
Signed-off-by: Andrew Bloomgarden <blmgrdn@amazon.com>
2022-03-21 23:49:17 +01:00
Alan Protasio 606ef33d91 Track and report Samples Queried per query
We always track total samples queried and add those to the standard set
of stats queries can report.

We also allow optionally tracking per-step samples queried. This must be
enabled both at the engine and query level to be tracked and rendered.
The engine flag is exposed via a Prometheus feature flag, while the
query flag is set when stats=all.

Co-authored-by: Alan Protasio <approtas@amazon.com>
Co-authored-by: Andrew Bloomgarden <blmgrdn@amazon.com>
Co-authored-by: Harkishen Singh <harkishensingh@hotmail.com>
Signed-off-by: Andrew Bloomgarden <blmgrdn@amazon.com>
2022-03-21 23:49:17 +01:00
Björn Rabenstein ec80745884
Merge pull request #10075 from prometheus/beorn7/histogram
model: Implement FloatHistogram.Compact
2022-01-05 16:09:39 +01:00
beorn7 3b4d6c3fdb model: Implement FloatHistogram.Compact
Signed-off-by: beorn7 <beorn@grafana.com>
2022-01-05 14:34:03 +01:00
beorn7 e7592fe353 sparsehistogram: Address two TODOs
Signed-off-by: beorn7 <beorn@grafana.com>
2022-01-04 12:48:59 +01:00
beorn7 a6acdfe346 histograms: Doc comment and naming improvements
Signed-off-by: beorn7 <beorn@grafana.com>
2021-12-15 16:50:37 +01:00
Ganesh Vernekar f580248759
Support + operator for sparse histograms (#9949)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-12-06 23:06:58 +05:30
Ganesh Vernekar 187a767292
Implement sum() for sparse histograms (#9948)
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-12-06 21:38:10 +05:30
Ganesh Vernekar 4a43349aca
histogram_quantile for sparse histograms (#9935)
* MergeFloatBucketIterator for []FloatBucketIterator

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* histogram_quantile for histograms

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix histogram_quantile

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Unit test and enhancements

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Iterators to iterate buckets in reverse and all buckets together including zero bucket

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Consider all buckets for histogram_quantile and fix the implementation

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Remove unneeded code

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>

* Fix lint

Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-12-06 19:17:22 +05:30
Björn Rabenstein 0e1b9dd308
Promql: Initial rate implementation for sparse histograms (#9926)
Signed-off-by: beorn7 <beorn@grafana.com>
2021-12-06 18:19:18 +05:30
beorn7 e4e24453fa Merge branch 'main' into beorn7/merge2 2021-11-30 17:19:06 +01:00
Shihao Xia 0e82a96e2f
fix potential deadlock in test (#9010)
* fix potential deadlock

Signed-off-by: Shihao Xia <charlesxsh@hotmail.com>

* fix deadlock

Signed-off-by: Shihao Xia <charlesxsh@hotmail.com>

* Update promql/engine_test.go

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Shihao Xia <charlesxsh@hotmail.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2021-11-27 12:45:06 +00:00
beorn7 5d4db805ac Merge branch 'main' into sparsehistogram 2021-11-17 19:57:31 +01:00
beorn7 9de3ab60df promql: improve histogram support in engine.go
Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-16 13:20:24 +01:00
beorn7 73858d7f82 storage: histogram support in memoized_iterator
Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-15 21:55:58 +01:00
beorn7 9b30ca2598 promql: Support histogram in value string representation
Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-15 20:36:44 +01:00
beorn7 4c28d9fac7 Move to histogram.Histogram pointers
This is to avoid copying the many fields of a histogram.Histogram all
the time.

This also fixes a bunch of formerly broken tests.

Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-12 23:17:35 +01:00
beorn7 f1065e44a4 model: String method for histogram.Histogram
This includes a regular bucket iterator and a string method for
histogram.Bucket.

Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-11 17:29:22 +01:00
Thomas Jackson f0003bc0ba
Don't drop ParenExpr when creating StepInvariantExpr (#9591)
* Add test case to showcase the problem in #9590

Signed-off-by: Thomas Jackson <jacksontj.89@gmail.com>

* Don't unwrap ParenExpr in newStepInvariantExpr

Fixes #9590

Signed-off-by: Thomas Jackson <jacksontj.89@gmail.com>
2021-11-10 20:16:24 +05:30
beorn7 c954cd9d1d Move packages out of deprecated pkg directory
This creates a new `model` directory and moves all data-model related
packages over there:
  exemplar labels relabel rulefmt textparse timestamp value

All the others are more or less utilities and have been moved to `util`:
  gate logging modetimevfs pool runtime

Signed-off-by: beorn7 <beorn@grafana.com>
2021-11-09 08:03:10 +01:00
Ganesh Vernekar c8b267efd6
Get histograms from TSDB to the rate() function implementation
Signed-off-by: Ganesh Vernekar <ganeshvern@gmail.com>
2021-11-03 19:04:18 +05:30
Mateusz Gozdek 1a6c2283a3 Format Go source files using 'gofumpt -w -s -extra'
Part of #9557

Signed-off-by: Mateusz Gozdek <mgozdekof@gmail.com>
2021-11-02 19:52:34 +01:00
Bryan Boreham a278ea4b58
promql: copy data when short-circuiting (#9552)
* promql: copy data when short-circuiting

Because the range query loop re-uses the output buffer each time round,
we must copy results into the buffer rather than using input as output.

Signed-off-by: Bryan Boreham <bjboreham@gmail.com>
2021-10-20 16:03:02 +02:00
Paweł Szulik f5563bfe95
tests: Move from t.Errorf and others. (Part 2) (#9309)
* Refactor util tests.

Signed-off-by: Paweł Szulik <paul.szulik@gmail.com>
2021-09-13 21:19:20 +02:00
Oleg Zaytsev b1ed4a0a66
LabelNames API with matchers (#9083)
* Push the matchers for LabelNames all the way into the index.

NB This doesn't actually implement it in the index, just plumbs it through for now...

Signed-off-by: Tom Wilkie <tom@grafana.com>

* Hack it up.  Does not work.

Signed-off-by: Tom Wilkie <tom@grafana.com>

* Revert changes I don't understand

Can't see why do we need to hold a mutex on symbols, and the purpose of
the LabelNamesFor method.

Maybe I'll need to re-add this later.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Implement LabelNamesFor

This method provides the label names that appear in the postings
provided. We do that deeper than the label values because we know
beforehand that most of the label names we'll be the same across
different postings, and we don't want to go down an up looking up the
same symbols for all different series.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Mutex on symbols should be unlocked

However, I still don't understand why do we need a mutex here.

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Fix head.LabelNamesFor

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Implement mockIndex LabelNames with matchers

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Nitpick on slice initialisation

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Add tests for LabelNamesWithMatchers

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Fix the mutex mess on head.LabelValues/LabelNames

I still don't see why we need to grab that unrelated mutex, but at least
now we're grabbing it consistently

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Check error after iterating postings

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Use the error from posting when there was en error in postings

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Update storage/interface.go comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go wrapped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go wrapped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Update tsdb/index/index.go warpped error msg

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* Remove unneeded comment

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Add testcases for LabelNames w/matchers in api.go

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

* Use t.Cleanup() instead of defer in tests

Signed-off-by: Oleg Zaytsev <mail@olegzaytsev.com>

Co-authored-by: Tom Wilkie <tom@grafana.com>
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2021-07-20 18:08:08 +05:30
Levi Harrison b5f6f8fb36 Switched to go-kit/log
Signed-off-by: Levi Harrison <git@leviharrison.dev>
2021-06-11 12:28:36 -04:00
Fiona Liao 9b83d8330a
Fix memSafeIterator.Seek() (#8748)
* Add range query test cases

This includes a couple of failing ones that double count some points due
to the iterator seek bug.

Co-authored-by: Oleg Zaytsev <mail@olegzaytsev.com>
Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com>

* Add Seek() implementation for memSafeIterator

Previously, calling memSafeIterator.Seek() would call the Seek() method
on its embedded iterator. This was causing the embedded iterator and the
memSafeIterator to get out of sync because when the embedded Seek()
moved to the next element of the embedded iterator, memSafeIterator
didn't "know" about it. memSafeIterator has to "know" when the embedded
iterator has moved to be able to work out when it should be reading from
its buffer rather than the embedded iterator.

Used same logic as for xorIterator.Seek() (which in runtime is used as
the embedded iterator) - return false if the iterator has an error and
try to move to next element if the required time hasn't been reached, or
if no elements have been read yet. The memSafeIterator.Next() method is
being called so memSafeIterator.i is always accurate.

Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com>

* Add tsdb package test

Signed-off-by: Fiona Liao <fiona.y.liao@gmail.com>

Co-authored-by: Oleg Zaytsev <mail@olegzaytsev.com>
2021-04-27 00:43:22 +02:00
schou 22cd48868a adding feature flag, promql-negative-offset
Signed-off-by: schou <pschou@users.noreply.github.com>
2021-02-23 20:25:56 -05:00
Tom Wilkie 7369561305
Combine Appender.Add and AddFast into a single Append method. (#8489)
This moves the label lookup into TSDB, whilst still keeping the cached-ref optimisation for repeated Appends.

This makes the API easier to consume and implement.  In particular this change is motivated by the scrape-time-aggregation work, which I don't think is possible to implement without it as it needs access to label values.

Signed-off-by: Tom Wilkie <tom.wilkie@gmail.com>
2021-02-18 17:37:00 +05:30
Mauro Stettler 7715fe3219
Add matchers to LabelValues() call (#8400)
* Accept matchers in querier LabelValues()

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* create matcher to only select metrics which have searched label

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* test case for merge querier with matchers

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* test LabelValues with matchers on head

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* add test for LabelValues on block

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* formatting fix

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* Add comments

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* add missing lock release

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* remove unused parameter

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* Benchmarks for LabelValues() methods on block/head

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* Better comment

Co-authored-by: Julien Pivotto <roidelapluie@gmail.com>
Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* update comment

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* minor refactor make code cleaner

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* better comments

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* fix expected errors in test

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* Deleting parameter which can only be empty

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* fix comments

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* remove unnecessary lock

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* only lookup label value if label name was looked up

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* Return error when there is one

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* Call .Get() on decoder before checking errors

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* only lock head.symMtx when necessary

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* remove unnecessary delete()

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* re-use code instead of duplicating it

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* Consistently return error from LabelValueFor()

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* move helper func from util.go to querier.go

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* Fix test expectation

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>

* ensure result de-duplication and sorting works

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

* return named error from LabelValueFor()

Signed-off-by: Mauro Stettler <mauro.stettler@gmail.com>

Co-authored-by: Julien Pivotto <roidelapluie@gmail.com>
Co-authored-by: Ganesh Vernekar <15064823+codesome@users.noreply.github.com>
2021-02-09 23:08:35 +05:30
Ganesh Vernekar 86c71856e8
Add start() and end() pre-processors for @ modifier (#8425)
* Add start() and end() pre-processors for @ modifier

Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>

* Fix reviews

Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>

* Fix review comments

Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>

* Fix review comments

Signed-off-by: Ganesh Vernekar <cs15btech11018@iith.ac.in>
2021-02-09 21:33:16 +05:30