THIS IS A TEST INSTANCE. ALL YOUR CHANGES WILL BE LOST!!!!
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Column statistics are introduced in Hive 0.10.0 by HIVE-1362. This is the design document. Column statistics auto gather is introduced in Hive 2.3 by HIVE-11160. This is also the design document. |
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Please note that table and column aliases are not supported in the analyze statement.
To view column stats :
describe formatted [table_name] [column_name];Metastore Schema
To persist column level statistics, we propose to add the following new tables,
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LOW_VALUE RAW,
HIGH_VALUE RAW,
NUM_NULLS BIGINT,
NUM_DISTINCTS BIGINT,
BIT_VECTOR, VARCHAR(16400)BLOB, /* introduced in HIVE-16997 in Hive 3.0.0 */
AVG_COL_LEN DOUBLE,
MAX_COL_LEN BIGINT,
NUM_TRUES BIGINT,
NUM_FALSES BIGINT,
LAST_ANALYZED BIGINT NOT NULL)
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LOW_VALUE RAW,
HIGH_VALUE RAW,
NUM_NULLS BIGINT,
NUM_DISTINCTS BIGINT,
BIT_VECTOR, VARCHAR(16400)BLOB, /* introduced in HIVE-16997 in Hive 3.0.0 */
AVG_COL_LEN DOUBLE,
MAX_COL_LEN BIGINT,
NUM_TRUES BIGINT,
NUM_FALSES BIGINT,
LAST_ANALYZED BIGINT NOT NULL)
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