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[C++] Reader cannot resolve Java fixed-offset writer timezone IDs such as GMT-00:00

Aperta
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@ffacs ci sta già lavorando.

Dal 29/9/2026.

  • #2716 di @ffacs — aperta

Valutazione

Difficoltà
3/5
Tempo stimato
1-2 giorni
Idoneità per principianti
68/100
Tipo di issue
Bug
Chiarezza
Abbastanza chiara
Stato di attività
Attiva
Stack tecnologico
cpp, java
Ambito
data-engineering, databases

Direzione di ricerca

Start with c++/src/Timezone.cc, especially getTimezoneByName and getTimezoneByFilename, then run orc-contents against the supplied gmt-0000.orc fixture. Confirm that the reader accepts the GMT-00:00 writerTimezone and still handles normal zoneinfo names correctly.

Scritto dal modello di indicizzazione a partire dal testo della issue.

Descrizione

I was closing out some old Arrow issues and this one (apache/arrow#21471, from 2019) looks like it is potentially an ORC bug rather than an Arrow one. I don't understand this domain well myself, so everything below the line was produced by Claude working through the ORC and Arrow source with me. I have checked that the reprex fails against current main (4dbfe288) as described, but I have not independently verified the code reading, so please treat it accordingly. I have tried to keep it concise.

Cause

When the JVM's default zone is a fixed offset, the Java writer records a custom ID such as GMT-00:00 or GMT+05:30 as the stripe writerTimezone (WriterImpl.java:563 uses TimeZone.getDefault().getID()). The Java reader accepts these because TimeZone.getTimeZone parses GMT±hh:mm (TreeReaderFactory.java:1251).

The C++ reader resolves a writer timezone only by opening $TZDIR/<name> (getTimezoneByName in c++/src/Timezone.cc), plus the US/* alias map from ORC-2011. No such file exists for GMT-00:00, so any stripe with a timestamp column fails:

$ orc-contents gmt-0000.orc
Caught exception in gmt-0000.orc: Time zone file /usr/share/zoneinfo/GMT-00:00 does not exist. Please install IANA time zone database and set TZDIR env.

Adding a GMT-00:00 symlink to GMT under TZDIR makes the same file read fine, so the timezone name is the only problem with it.

Reprex

gmt-0000.orc (250 bytes) has one stripe, one timestamp column, uncompressed, with writerTimezone set to GMT-00:00. It was written with the C++ writer via pyorc (with TZDIR pointed at a directory containing a GMT-00:00 zone file) to reproduce the footer field that Hive produced in the original report.

gmt-0000.orc as base64 (decode with base64 -d) 
T1JDCgYSBAgBUAAKHgoEAAAAABIWCAFKEBjA2u/vslogwNrv77JaMAFQAHYAD9kwyEAAAAoGCAYQABgICgYIBhABGCAKBggBEAEYBgoGCAUQARgDEgQIABAAEgQIAhAAGglHTVQtMDA6MDAKHgoECAFQAAoWCAFKEBjA2u/vslogwNrv77JaMAFQAAgDEGgaCggDECgYCSA3KAEiDwgMEgEBGgJ0cyAAKAAwACIICAkgACgAMAAwAToECAFQADoWCAFKEBjA2u/vslogwNrv77JaMAFQAECQTkgBYgUyLjEuNAhXEAAYgIAEIgIADCggMAaC9AMDT1JDFw==

Suggested fix (untested)

Recognise names matching GMT[+-]hh(:mm)? in getTimezoneByFilename and return a fixed-offset Timezone instead of loading a file. The Etc/GMT±n zoneinfo files are not a substitute since they only cover whole hours and use the inverted POSIX sign.

Lingua principale
Java
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Fork
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