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Posted to issues@spark.apache.org by "Zhenhua Wang (Jira)" <ji...@apache.org> on 2022/02/08 12:50:00 UTC
[jira] [Updated] (SPARK-38140) Column stats (min, max) for timestamp type is not consistent with the value due to time zone difference
[ https://issues.apache.org/jira/browse/SPARK-38140?page=com.atlassian.jira.plugin.system.issuetabpanels:all-tabpanel ]
Zhenhua Wang updated SPARK-38140:
---------------------------------
Description:
Currently timestamp column's stats (min/max) are stored in UTC in metastore, and when desc its min/max column stats, they are also shown in UTC.
As a result, for users not in UTC, the column stats are not consistent with the actual value, which causes confusion.
For example:
{noformat}
spark-sql> create table tab_ts_master (ts timestamp) using parquet;
spark-sql> insert into tab_ts_master values make_timestamp(2022, 1, 1, 0, 0, 1.123456), make_timestamp(2022, 1, 3, 0, 0, 2.987654);
spark-sql> select * from tab_ts_master;
2022-01-01 00:00:01.123456
2022-01-03 00:00:02.987654
spark-sql> set spark.sql.session.timeZone;
spark.sql.session.timeZone Asia/Shanghai
spark-sql> analyze table tab_ts_master compute statistics for all columns;
spark-sql> desc formatted tab_ts_master ts;
col_name ts
data_type timestamp
comment NULL
min 2021-12-31 16:00:01.123456
max 2022-01-02 16:00:02.987654
num_nulls 0
distinct_count 2
avg_col_len 8
max_col_len 8
histogram NULL
{noformat}
was:
Currently timestamp column's stats (min/max) are stored in UTC in metastore, and when desc its min/max column stats, they are also shown in UTC.
As a result, for users not in UTC, the column stats are not consistent with the actual value, which causes confusion.
For example:
spark-sql> create table tab_ts_master (ts timestamp) using parquet;
spark-sql> insert into tab_ts_master values make_timestamp(2022, 1, 1, 0, 0, 1.123456), make_timestamp(2022, 1, 3, 0, 0, 2.987654);
spark-sql> select * from tab_ts_master;
2022-01-01 00:00:01.123456
2022-01-03 00:00:02.987654
spark-sql> set spark.sql.session.timeZone;
spark.sql.session.timeZone Asia/Shanghai
spark-sql> analyze table tab_ts_master compute statistics for all columns;
spark-sql> desc formatted tab_ts_master ts;
col_name ts
data_type timestamp
comment NULL
min 2021-12-31 16:00:01.123456
max 2022-01-02 16:00:02.987654
num_nulls 0
distinct_count 2
avg_col_len 8
max_col_len 8
histogram NULL
> Column stats (min, max) for timestamp type is not consistent with the value due to time zone difference
> -------------------------------------------------------------------------------------------------------
>
> Key: SPARK-38140
> URL: https://issues.apache.org/jira/browse/SPARK-38140
> Project: Spark
> Issue Type: Bug
> Components: SQL
> Affects Versions: 3.1.2, 3.2.1
> Reporter: Zhenhua Wang
> Priority: Minor
>
> Currently timestamp column's stats (min/max) are stored in UTC in metastore, and when desc its min/max column stats, they are also shown in UTC.
> As a result, for users not in UTC, the column stats are not consistent with the actual value, which causes confusion.
> For example:
> {noformat}
> spark-sql> create table tab_ts_master (ts timestamp) using parquet;
> spark-sql> insert into tab_ts_master values make_timestamp(2022, 1, 1, 0, 0, 1.123456), make_timestamp(2022, 1, 3, 0, 0, 2.987654);
> spark-sql> select * from tab_ts_master;
> 2022-01-01 00:00:01.123456
> 2022-01-03 00:00:02.987654
> spark-sql> set spark.sql.session.timeZone;
> spark.sql.session.timeZone Asia/Shanghai
> spark-sql> analyze table tab_ts_master compute statistics for all columns;
> spark-sql> desc formatted tab_ts_master ts;
> col_name ts
> data_type timestamp
> comment NULL
> min 2021-12-31 16:00:01.123456
> max 2022-01-02 16:00:02.987654
> num_nulls 0
> distinct_count 2
> avg_col_len 8
> max_col_len 8
> histogram NULL
> {noformat}
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