lidavidm commented on code in PR #37088:
URL: https://github.com/apache/arrow/pull/37088#discussion_r1290072459
##########
java/adapter/jdbc/src/main/java/org/apache/arrow/adapter/jdbc/JdbcToArrowUtils.java:
##########
@@ -188,12 +188,9 @@ public static ArrowType getArrowTypeFromJdbcType(final
JdbcFieldInfo fieldInfo,
case Types.TIME:
return new ArrowType.Time(TimeUnit.MILLISECOND, 32);
case Types.TIMESTAMP:
- final String timezone;
- if (calendar != null) {
- timezone = calendar.getTimeZone().getID();
- } else {
- timezone = null;
- }
+ return new ArrowType.Timestamp(TimeUnit.MILLISECOND);
+ case Types.TIMESTAMP_WITH_TIMEZONE:
+ final String timezone = calendar == null ? null :
calendar.getTimeZone().getID();
Review Comment:
Ok, so Snowflake:
> TIMESTAMP_LTZ internally stores UTC time with a specified precision.
However, all operations are performed in the current session’s time zone,
controlled by the
[TIMEZONE](https://docs.snowflake.com/en/sql-reference/parameters.html#label-timezone)
session parameter.
> TIMESTAMP_TZ internally stores UTC time together with an associated time
zone offset. When a time zone is not provided, the session time zone offset is
used. All operations are performed with the time zone offset specific to each
record.
Postgres:
> All timezone-aware dates and times are stored internally in UTC.
So the underlying value should be UTC. I think you'll have to look at what
their JDBC driver specifically does, though: it might localize the value for
you. I think you may need database-specific converters?
##########
java/adapter/jdbc/src/main/java/org/apache/arrow/adapter/jdbc/JdbcToArrowUtils.java:
##########
@@ -188,12 +188,9 @@ public static ArrowType getArrowTypeFromJdbcType(final
JdbcFieldInfo fieldInfo,
case Types.TIME:
return new ArrowType.Time(TimeUnit.MILLISECOND, 32);
case Types.TIMESTAMP:
- final String timezone;
- if (calendar != null) {
- timezone = calendar.getTimeZone().getID();
- } else {
- timezone = null;
- }
+ return new ArrowType.Timestamp(TimeUnit.MILLISECOND);
+ case Types.TIMESTAMP_WITH_TIMEZONE:
+ final String timezone = calendar == null ? null :
calendar.getTimeZone().getID();
Review Comment:
Ok, so Snowflake:
> TIMESTAMP_LTZ internally stores UTC time with a specified precision.
However, all operations are performed in the current session’s time zone,
controlled by the
[TIMEZONE](https://docs.snowflake.com/en/sql-reference/parameters.html#label-timezone)
session parameter.
> TIMESTAMP_TZ internally stores UTC time together with an associated time
zone offset. When a time zone is not provided, the session time zone offset is
used. All operations are performed with the time zone offset specific to each
record.
Postgres:
> All timezone-aware dates and times are stored internally in UTC.
So the underlying value should be UTC. I think you'll have to look at what
their JDBC driver specifically does, though: it might localize the value for
you. I think you may need database-specific converters?
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