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feat(operator): read a timestamp cast over the years the engine reaches - #8597

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@kz930 kz930 commented Sep 18, 2026 •

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What changes were proposed in this PR?

Type Casting to a timestamp read text with pd.to_datetime(col, errors="coerce") in the exported script. That is wrong in two ways, and both empty a cell the run itself filled.

pandas parses into nanoseconds, which reach only 1677-09-21 to 2262-04-11. The engine holds a java.sql.Timestamp, where 2500-01-01 00:00:00 is an ordinary moment: it reads it, and the exported script answered with an empty cell. The same for 1500-06-15 08:30:00 and 9999-12-31 23:59:59.

pandas also infers one format for the whole column and coerces every row that does not match it. The engine hands DateParserUtils one field at a time, so a row states its own format. A column holding 2024-03-05 14:09:07 and March 5, 2024 kept the first and emptied the second.

The text branch now reads the column cell by cell and holds the result at microsecond resolution, which covers the years the engine covers. It still coerces: the engine accepts a set of formats no single pandas call states, so text neither side can read leaves an empty cell rather than ending an exported run halfway. That part is unchanged, and a test now says so.

Review and the verification's edge values found more places where the cast parted from the engine:

  • A reading that states an offset, such as Z or +05:30, stopped the cast. The engine moves it to the machine's zone and keeps that wall clock, and the script now does the same.
  • A column that already held timestamps went through the text parse and lost its nanoseconds. parseField returns a java.sql.Timestamp untouched, so the script now hands such a column back at the resolution it arrived in.
  • Text with digits past the millisecond kept them. DateParserUtils reads into a java.util.Date, which counts milliseconds, so the script now cuts there too.
  • Casting to text wrote a value the way Python's str() does. Java writes a double past 1e7 or under 1e-3 in E notation, a boolean in lower case, and a timestamp with its nanoseconds and at least .0. A shared _texera_java_text now writes each one as Java's toString does.
  • A double column holding a NaN as a value, as an Arrow or Parquet source hands one over, lost it. The casts asked each cell whether it was empty, and pandas hands an empty cell over as NaN too, so a stored NaN came out null where the engine writes NaN as text, 0 as an integer and true as a boolean. The casts now read empty cells from the column's own mask, and the double cast builds a nullable Float64, so a NaN read from text stays one through the next cast. A double past an integer's bounds now saturates as toInt and toLong do, where int() raised on an infinity.
  • A moment was read with dateutil's tzlocal(), which knows only today's two offsets, so an instant from before a zone changed its rules came out an hour or more off on every platform. The script now reads the machine's zone by its IANA name and, before 1900, keeps today's standard offset as java.util.Date does.
  • On Windows, localtime refuses an instant before 1970, which stopped the cast. The same helper now falls back to the zone's standard offset there.

That Float64 column changed what a Python operator after this cast is handed. pyamber hands a Python operator a DOUBLE column as float64, where a NaN and a null are one value, and writes a NaN out as null. Given Float64 instead, Sort ordered a NaN apart from the nulls, a chart drew points the engine dropped, and a passed-through NaN stayed NaN. StandaloneCodeGenerator gains standaloneInputAdapter(), and for a Python operator the translator feeds the fragment a float64 copy of each input, leaving the upstream frame as it was.

The number branch is left alone. A LONG is read as epoch milliseconds and has the same window, but it also disagrees about the calendar before 1582-10-15, where new Timestamp(long) is Julian and pandas is proleptic Gregorian. Widening the window there would answer with a moment eight days off instead of an empty cell, so what that branch should do is a separate decision. The issue records it.

Any related issues, documentation, discussions?

Closes #8595. #8480 closed the same nanosecond gap for Extract Date/Time Fields, which parses strictly and could take the one-line form this operator cannot.

#8341, #8704, #8705 and #8709 call the timestamp and text helpers this adds, so this PR merges before them.

How was this PR tested?

Eight tests in TypeCastingOpDescSpec run the generated Python and compare it cell by cell against AttributeTypeUtils.parseField. They are tagged to run in the integration job, which has pandas.

  • The text-to-timestamp test reads moments in three formats, the rows either side of the nanosecond edge, 2500-01-01, 1500-06-15, 9999-12-31, readings with Z and +05:30, and readings past the millisecond. It fails on the old generator.
  • One test gives a column that already holds timestamps and checks its nanoseconds are kept.
  • The cast-to-string test covers a double at 1e7 and 1e-4.
  • One test checks that unreadable text still leaves an empty cell, where the engine refuses it.
  • Two tests cast a column holding a stored NaN, both infinities and an empty cell to each type and compare against AttributeTypeUtils, and check that a NaN read from text survives a second cast.
  • Two tests read moments from America/Mexico_City in 1899, 1921, 1931 and 2021, at the offset the zone had then, and the same moments with localtime refusing those before 1970.
  • Three tests in WorkflowToPythonTranslatorSpec check that a Python operator reads a converted copy of its input and an operator the engine runs on the JVM reads its upstream as it is. Two of them fail without the change.

Was this PR authored or co-authored using generative AI tooling?

Generated-by: Claude Code (Claude Opus 5)

pandas parses into nanoseconds, which reach only 1677 to 2262, so the exported
script emptied every moment outside that window where the engine holds a
java.sql.Timestamp and reads it like any other. It also inferred one format for
the whole column, so a row written differently from the first one was emptied
too, where the engine hands DateParserUtils a field at a time.

The text branch now reads the column cell by cell at microsecond resolution.
Text neither side can read still leaves an empty cell rather than ending the
run, which is what the cast has always promised.

Closes apache#8595

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
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github-actions Bot commented Sep 18, 2026 •

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⚠️ Benchmark changes need a look

🟢 2 better · 🔴 9 worse · ⚪ 4 noise (<±5%) · 0 without baseline

Compared against main 5264df2 benchmarked on this same runner, so the delta is largely free of cross-runner hardware noise. The "7d avg" column still reflects the gh-pages dashboard. Treat <±5% as noise unless repeated.

Dashboard · Run

config throughput MB/s latency max Δ latest / 7d
🔴 bs=10 sw=10 sl=64 363 0.222 26,741/37,261/37,261 us 🔴 +18.2% / 🔴 +155.1%
🔴 bs=100 sw=10 sl=64 767 0.468 126,909/163,976/163,976 us 🔴 +13.4% / 🔴 +63.7%
🟢 bs=1000 sw=10 sl=64 908 0.554 1,102,901/1,199,715/1,199,715 us 🟢 -7.8% / 🔴 +29.8%
Baseline details

Latest main 5264df2 from same runner

config metric PR latest main 7d avg Δ latest Δ 7d
bs=10 sw=10 sl=64 throughput 363 tuples/sec 411 tuples/sec 912.36 tuples/sec -11.7% -60.2%
bs=10 sw=10 sl=64 MB/s 0.222 MB/s 0.251 MB/s 0.557 MB/s -11.6% -60.1%
bs=10 sw=10 sl=64 p50 26,741 us 22,628 us 11,391 us +18.2% +134.7%
bs=10 sw=10 sl=64 p95 37,261 us 34,187 us 14,608 us +9.0% +155.1%
bs=10 sw=10 sl=64 p99 37,261 us 34,187 us 17,250 us +9.0% +116.0%
bs=100 sw=10 sl=64 throughput 767 tuples/sec 811 tuples/sec 1,161 tuples/sec -5.4% -34.0%
bs=100 sw=10 sl=64 MB/s 0.468 MB/s 0.495 MB/s 0.709 MB/s -5.5% -34.0%
bs=100 sw=10 sl=64 p50 126,909 us 122,407 us 91,471 us +3.7% +38.7%
bs=100 sw=10 sl=64 p95 163,976 us 144,572 us 100,192 us +13.4% +63.7%
bs=100 sw=10 sl=64 p99 163,976 us 144,572 us 119,565 us +13.4% +37.1%
bs=1000 sw=10 sl=64 throughput 908 tuples/sec 920 tuples/sec 1,226 tuples/sec -1.3% -25.9%
bs=1000 sw=10 sl=64 MB/s 0.554 MB/s 0.562 MB/s 0.748 MB/s -1.4% -26.0%
bs=1000 sw=10 sl=64 p50 1,102,901 us 1,081,070 us 887,282 us +2.0% +24.3%
bs=1000 sw=10 sl=64 p95 1,199,715 us 1,301,809 us 924,352 us -7.8% +29.8%
bs=1000 sw=10 sl=64 p99 1,199,715 us 1,301,809 us 951,858 us -7.8% +26.0%
Raw CSV
config_idx,batch_size,schema_width,string_len,num_batches,total_ms,total_tuples,total_bytes,tuples_per_sec,mb_per_sec,lat_p50_us,lat_p95_us,lat_p99_us
0,10,10,64,20,550.63,200,128000,363,0.222,26740.74,37261.49,37261.49
1,100,10,64,20,2609.02,2000,1280000,767,0.468,126909.24,163976.18,163976.18
2,1000,10,64,20,22016.35,20000,12800000,908,0.554,1102900.94,1199714.71,1199714.71

@codecov-commenter

codecov-commenter commented Sep 18, 2026 •

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Codecov Report

❌ Patch coverage is 66.66667% with 1 line in your changes missing coverage. Please review.
✅ Project coverage is 92.56%. Comparing base (2ab8ee0) to head (f0eedd9).
⚠️ Report is 149 commits behind head on main.

Files with missing lines Patch % Lines
.../amber/translator/WorkflowToPythonTranslator.scala 66.66% 0 Missing and 1 partial ⚠️
Additional details and impacted files
@@             Coverage Diff              @@
##               main    #8597      +/-   ##
============================================
- Coverage     92.78%   92.56%   -0.22%     
- Complexity     4898     5060     +162     
============================================
  Files          1236     1245       +9     
  Lines         52121    53090     +969     
  Branches       6405     6542     +137     
============================================
+ Hits          48359    49143     +784     
- Misses         2186     2307     +121     
- Partials       1576     1640      +64     
Flag Coverage Δ *Carryforward flag
access-control-service 77.38% <ø> (+5.59%) ⬆️
agent-service 99.32% <ø> (ø) Carriedforward from 7a3203d
amber 88.09% <ø> (-0.51%) ⬇️ Carriedforward from 7a3203d
computing-unit-managing-service 60.48% <ø> (+5.28%) ⬆️
config-service 87.37% <ø> (ø)
file-service 82.00% <ø> (+0.47%) ⬆️ Carriedforward from 7a3203d
frontend 96.58% <ø> (ø) Carriedforward from 7a3203d
notebook-migration-service 83.73% <ø> (ø)
pyamber 98.48% <ø> (ø) Carriedforward from 7a3203d
workflow-compiling-service 74.05% <66.66%> (-0.05%) ⬇️

*This pull request uses carry forward flags. Click here to find out more.

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The new timestamp helper crashes on 2024-03-05T14:09:07Z. I ran the generated helper with pandas 2.2.3. Parsing keeps the timezone, then astype rejects the conversion to a timestamp without a timezone. The previous code accepts this value. Please handle timestamps with a timezone and add a test with Z and an explicit offset.

The cast stopped on one. A reading that carries a zone cannot be converted to a
column that holds none, so `2024-03-05T14:09:07Z` ended the cast where the
previous generator had read it, and an explicit offset did the same.

The engine reads the offset and keeps no zone for it: DateParserUtils parses the
reading and java.sql.Timestamp holds the wall clock of the machine's own zone,
so `...T14:09:07Z` is 06:09:07 where the machine is eight hours behind UTC. The
helper now does that, which is also what the epoch-milliseconds branch beside it
already did.

The two spellings join the cases the timestamp test compares against
parseField cell by cell, so what they should read is taken from the engine
rather than written down and the pair says the same thing in any zone.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>
@kz930

kz930 commented Sep 19, 2026

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Fixed in c07493387. The helper now does what the engine does with an offset — DateParserUtils reads it and java.sql.Timestamp keeps no zone, so the moment is held as the wall clock of the machine's own zone (...T14:09:07Z is 06:09:07 eight hours behind UTC) — and both spellings joined the cases the test compares against parseField cell by cell, so the expectation comes from the engine rather than being written down.

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The timezone crash is fixed. I ran the current helper with Z, an explicit offset, year 2500, and null. Those checks passed.

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Reproduced locally with the generated Python code. One correctness issue below. I did not run a frontend workflow or the full Scala suite.

The cast narrowed one. A column the engine already holds as a moment went
through the same astype as freshly parsed text, so 14:09:07.123456789 and
14:09:07.123456001 both came back as .123456 and two rows the run tells apart
became one. The previous generator left such a column alone.

parseField hands a java.sql.Timestamp back untouched and that class counts
nanoseconds, so there is nothing for this branch to decide: the column is
returned at the resolution it arrived in, zoned or not. The text branch below
is unchanged and still reads into microseconds, which is what the years past
the nanosecond edge need.

A test casts a timestamp column to timestamp and compares the two values cell
by cell against parseField, which is how the rest of the spec compares a cast.

Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>

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Retested ca67ce1. Timezone inputs, extended years and nanosecond precision pass. The previous findings are fixed. Looks good.

… write text as Java's toString does

Co-Authored-By: Claude Opus 5.5 (1M context) <noreply@anthropic.com>
@kz930

kz930 commented Sep 27, 2026

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@carloea2 Since your approval, text read into a timestamp is cut to the millisecond as DateParserUtils does, and a cast to text writes a value as Java's toString does.

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Retested with JDK 17.0.20.1. The helper still writes 1.0E23 where the engine writes 9.999999999999999E22. The JDK 19 form would keep this mismatch. We need maintainer agreement on the supported formatting contract before accepting that difference.

kz930 and others added 2 commits October 12, 2026 15:10
The helper writes a double's shortest digits, as Double.toString does
from JDK 19. On JDK 17 the engine sometimes writes more digits for the
same value, so say so where the text is built.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
@kz930

kz930 commented Oct 12, 2026

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@carloea2 Per Xinyuan's call on the thread, the helper keeps the shortest form and the JDK 17 difference is noted in a comment on _texera_java_text (2b1dcf5). Could you take another look?

The access-control-service job could not resolve
io.fabric8:kubernetes-client:6.12.1 before any test ran.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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The documented JDK 17 difference is accepted by Xinyuan, so that earlier finding is no longer a blocker. All 13 focused casting tests and scalafmtCheckAll pass locally. A separate Arrow NaN regression fails at this head.

kz930 and others added 2 commits October 12, 2026 19:24
…ring

A nullable float column read from Arrow holds NaN as a value, but
Series.map hands its empty cells over as NaN too, so the cast emptied a
stored NaN the engine writes as "NaN". Read the empty cells from the
column's own mask instead.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
…ne does

The integer, long and boolean casts asked each value whether it was
empty, and Series.apply hands a nullable float column's empty cells over
as NaN, so a stored NaN came out null where the engine gives 0, 0 and
true. They now read the column's own mask, as the string cast does.

A double past an integer's bounds now saturates as toInt and toLong do,
where int() raised on an infinity and stopped the script.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
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kz930 commented Oct 13, 2026

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@carloea2 The stored-NaN cast is fixed in d966535, with a parity test against AttributeTypeUtils. Could you take another look?

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The stored Arrow NaN fix passes. Two other cases remain in the generated casts: NaN parsed as DOUBLE becomes null on the next STRING cast, and a valid pre Unix epoch LONG crashes the timestamp cast on Windows. The existing 10 tests pass; my additional cases give 3 passes and 2 failures. Formatting passes.

sbt -batch 'WorkflowOperator/testOnly *TypeCastingOpDescSpec -- -oDF'

…pre-1970 milliseconds on Windows

The double cast wrote float64, which holds a NaN and an empty cell alike,
so text "NaN" cast to DOUBLE came out null at the next cast to STRING. It
now builds a nullable Float64 from the column's own mask.

Windows' localtime refuses an instant before 1970, so the LONG to
TIMESTAMP cast stopped on one. Such a cell now takes the zone's standard
offset, which is what java.sql.Timestamp writes before 1900.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
@kz930

kz930 commented Oct 13, 2026

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@carloea2 Both cases are fixed in 5d46525, with tests for each. Could you take another look?

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kz930 commented Oct 13, 2026

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@carloea2 both cast cases from your last review are fixed in 5d46525. Could you take another look?

The previous fix covered epoch milliseconds only. Text that states an
offset and a column that states its zone also asked tzlocal() for the
wall clock, so on Windows an instant before 1970 still stopped the cast.
All three now go through one helper that falls back to the zone's
standard offset, and a zoned column keeps its own resolution.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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The earlier NaN round trip and pre-1970 crash fixes pass: all 12 author tests and formatting checks are green. A historical timezone case still differs on Windows. At 1931-01-01T00:00:00Z in America/Mexico_City, the generated cast returns 1930-12-31 18:00; the native JVM returns 17:00. Modern, older-summer and null controls pass. The added historical regression fails. No production edits or dependency fixtures used.

sbt -batch 'WorkflowOperator/testOnly *TypeCastingOpDescSpec -- -oDF' 'scalafmtCheckAll'

sbt -batch 'WorkflowOperator/testOnly *TimestampHistoryReviewSpec -- -oDF'

…instant

dateutil's tzlocal() knows only today's standard and daylight offsets, so
an instant from before a zone changed its rules was read an hour or more
away from the engine, on every platform. Read the machine's zone by its
IANA name instead, through tzlocal, TZ or /etc/localtime, and keep
today's standard offset before 1900 as java.util.Date does.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
@kz930

kz930 commented Oct 14, 2026

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@carloea2 The historical offset case is fixed in 7a3203d. Could you take another look?

pyamber hands a Python operator a DOUBLE column as float64, where a NaN and a
null are one value, and writes a NaN out as null. The double cast here builds
Float64, which keeps them apart, so a Python operator after it answered
differently: Sort ordered a NaN apart from the nulls, a chart drew a point the
engine dropped, and a passed-through NaN stayed NaN. StandaloneCodeGenerator
gains standaloneInputAdapter(), and for a Python operator the translator feeds
the fragment a converted copy of each input, leaving the upstream frame as it was.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
@kz930

kz930 commented Oct 16, 2026

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@carloea2 I added f0eedd9. The double cast now builds Float64, and a Python operator after it was handed a NaN that pyamber would have turned into null, so the translator now feeds Python operators a float64 copy the way pyamber does. I updated the description to cover this and the earlier rounds; could you take another look?

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The historical timezone finding is fixed. On Windows with JDK 17, all 13 TypeCastingOpDescSpec tests, my 3 historical timezone regressions, and 13 translator tests pass against current upstream main. scalafmtCheckAll passes too. CI for this head is still queued.

Command: sbt -batch "WorkflowOperator/testOnly *TypeCastingOpDescSpec *TimestampHistoryReviewSpec" "WorkflowCompilingService/testOnly *WorkflowToPythonTranslatorSpec" scalafmtCheckAll

@github-actions github-actions Bot added the platform Non-amber Scala service paths label Oct 16, 2026
kz930 added a commit to kz930/texera that referenced this pull request Oct 16, 2026
…offset

A timestamp value with an offset now becomes the machine-zone wall clock
through apache#8597's _texera_local_wall_clock, which uses the zone's IANA history
instead of Windows localtime. Adds a Mexico City test for 2021 summer time
and 1931.

Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>

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Casting text to a timestamp empties a moment the engine reads

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