Before this patch the supported year range for DATE type started with
year 0. This contradicts the ANSI SQL standard that defines the valid
DATE value range to be 0001-01-01 to 9999-12-31.
Change-Id: Iefdf1c036834763f52d44d0c39a25a1f04e41e07
Reviewed-on: http://gerrit.cloudera.org:8080/14349
Reviewed-by: Attila Jeges <attilaj@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
This enhancement introduces FORMAT clause for CAST() operator that is
applicable for casts between string types and timestamp types. Instead
of accepting SimpleDateFormat patterns the FORMAT clause supports
datetime patterns following the ISO:SQL:2016 standard.
Note, the CAST() operator without the FORMAT clause still uses
Impala's implementation of SimpleDateFormat handling. Similarly, the
existing conversion functions such as to_timestamp(), from_timestamp()
etc. remain unchanged and use SimpleDateFormat. Contrary to how these
functions work the FORMAT clause must specify a string literal and
cannot be used with any other kind of a string expression.
Milestone 1 contains all the format tokens covered by the SQL
standard. Further milestones will add more functionality on top of
this list to cover functionality provided by other RDBMS systems.
List of tokens implemented by this change:
- YYYY, YYY, YY, Y: Year tokens
- RRRR, RR: Round year tokens
- MM: Month (1-12)
- DD: Day (1-31)
- DDD: Day of year (1-366)
- HH, HH12: Hour of day (1-12)
- HH24: Hour of day (0-23)
- MI: Minute (0-59)
- SS: Second (0-59)
- SSSSS: Second of day (0-86399)
- FF, FF1, ..., FF9: Fractional second
- AM, PM, A.M., P.M.: Meridiem indicators
- TZH: Timezone hour (-99-+99)
- TZM: Timezone minute (0-99)
- Separators: - . / , ' ; : space
- ISO8601 date indicators (T, Z)
Some notes about the matching algorithm:
- The parsing algorithm uses these tokens in a case insensitive
manner.
- The separators are interchangeable with each other. For example a
'-' separator in the format will match with a '.' character in the
input.
- The length of the separator sequences is handled flexibly meaning
that a single separator character in the format for instance would
match with a multi-separator sequence in the input.
- In a string type to timestamp conversion the timezone offset tokens
are parsed, expected to match with the input but they don't adjust
the result as the input is already expected to be in UTC format.
Usage example:
SELECT CAST('01-02-2019' AS TIMESTAMP FORMAT 'MM-DD-YYYY');
SELECT CAST('2019.10.10 13:30:40.123456 +01:30' AS TIMESTAMP
FORMAT 'YYYY-MM-DD HH24:MI:SS.FF9 TZH:TZM');
SELECT CAST(timestamp_column as STRING
FORMAT "YYYY MM HH12 YY") from some_table;
Change-Id: I19d8d097a45ae6f103b6cd1b2d81aad38dfd9e23
Reviewed-on: http://gerrit.cloudera.org:8080/13722
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
This change extends the error message Impala yields when casting STRING
to DATE (explicitly or implicitly) fails. The new error message includes
the violating string value.
Testing:
changes -> date-partitioning.test & date.test
query_test/test_date_queries.py test passed
Example:
select cast('20' as date);
ERROR: UDF ERROR: String to Date parse failed. Invalid string val: "20"
Change-Id: If800b7696515cd61afee27220c55ff2440a86f04
Reviewed-on: http://gerrit.cloudera.org:8080/13680
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
DATE values describe a particular year/month/day in the form
yyyy-MM-dd. For example: DATE '2019-02-15'. DATE values do not have a
time of day component. The range of values supported for the DATE type
is 0000-01-01 to 9999-12-31.
This initial DATE type support covers TEXT and HBASE fileformats only.
'DateValue' is used as the internal type to represent DATE values.
The changes are as follows:
- Support for DATE literal syntax.
- Explicit casting between DATE and other types (note that invalid
casts will fail with an error just like invalid DECIMAL_V2 casts,
while failed casts to other types do no lead to warning or error):
- from STRING to DATE. The string value must be formatted as
yyyy-MM-dd HH:mm:ss.SSSSSSSSS. The date component is mandatory,
the time component is optional. If the time component is
present, it will be truncated silently.
- from DATE to STRING. The resulting string value is formatted as
yyyy-MM-dd.
- from TIMESTAMP to DATE. The source timestamp's time of day
component is ignored.
- from DATE to TIMESTAMP. The target timestamp's time of day
component is set to 00:00:00.
- Implicit casting between DATE and other types:
- from STRING to DATE if the source string value is used in a
context where a DATE value is expected.
- from DATE to TIMESTAMP if the source date value is used in a
context where a TIMESTAMP value is expected.
- Since STRING -> DATE, STRING -> TIMESTAMP and DATE -> TIMESTAMP
implicit conversions are now all possible, the existing function
overload resolution logic is not adequate anymore.
For example, it resolves the
if(false, '2011-01-01', DATE '1499-02-02') function call to the
if(BOOLEAN, TIMESTAMP, TIMESTAMP) version of the overloaded
function, instead of the if(BOOLEAN, DATE, DATE) version.
This is clearly wrong, so the function overload resolution logic had
to be changed to resolve function calls to the best-fit overloaded
function definition if there are multiple applicable candidates.
An overloaded function definition is an applicable candidate for a
function call if each actual parameter in the function call either
matches the corresponding formal parameter's type (without casting)
or is implicitly castable to that type.
When looking for the best-fit applicable candidate, a parameter
match score (i.e. the number of actual parameters in the function
call that match their corresponding formal parameter's type without
casting) is calculated and the applicable candidate with the highest
parameter match score is chosen.
There's one more issue that the new resolution logic has to address:
if two applicable candidates have the same parameter match score and
the only difference between the two is that the first one requires a
STRING -> TIMESTAMP implicit cast for some of its parameters while
the second one requires a STRING -> DATE implicit cast for the same
parameters then the first candidate has to be chosen not to break
backward compatibility.
E.g: year('2019-02-15') function call must resolve to
year(TIMESTAMP) instead of year(DATE). Note, that year(DATE) is not
implemented yet, so this is not an issue at the moment but it will
be in the future.
When the resolution algorithm considers overloaded function
definitions, first it orders them lexicographically by the types in
their parameter lists. To ensure the backward compatible behavior
Primitivetype.DATE enum value has to come after
PrimitiveType.TIMESTAMP.
- Codegen infrastructure changes for expression evaluation.
- 'IS [NOT] NULL' and '[NOT] IN' predicates.
- Common comparison operators (including the 'BETWEEN' operator).
- Infrastructure changes for built-in functions.
- Some built-in functions: conditional, aggregate, analytical and
math functions.
- C++ UDF/UDA support.
- Support partitioning and grouping by DATE.
- Beeswax, HiveServer2 support.
These items are tightly coupled and it makes sense to implement them
in one change-set.
Testing:
- A new partitioned TEXT table 'functional.date_tbl' (and the
corresponding HBASE table 'functional_hbase.date_tbl') was
introduced for DATE-related tests.
- BE and FE tests were extended to cover DATE type.
- E2E tests:
- since DATE type is supported for TEXT and HBASE fileformats
only, most DATE tests were implemented separately in
tests/query_test/test_date_queries.py.
Note, that this change-set is not a complete DATE type implementation,
but it lays the foundation for future work:
- Add date support to the random query generator.
- Implement a complete set of built-in functions.
- Add Parquet support.
- Add Kudu support.
- Optionally support Avro and ORC.
For further details, see IMPALA-6169.
Change-Id: Iea8155ef09557e0afa2f8b2d0b2dc9d0896dc30f
Reviewed-on: http://gerrit.cloudera.org:8080/12481
Reviewed-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
Tested-by: Impala Public Jenkins <impala-public-jenkins@cloudera.com>
