Details
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Bug
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Status: Closed (View Workflow)
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Critical
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Resolution: Duplicate
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N/A
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None
Description
Upon request, I intentionally make tables bigger than they need to be for reproducing the problem, so that both the number of rows and the number of unique values exceed the histogram size.
--source include/have_sequence.inc
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CREATE TABLE t1 (f TIME) ENGINE=MyISAM; |
INSERT INTO t1 SELECT IF(seq%2,'00:00:00',SEC_TO_TIME(seq+7200)) FROM seq_1_to_1000; |
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SET histogram_type= JSON_HB; |
ANALYZE TABLE t1 PERSISTENT FOR ALL; |
ANALYZE FORMAT=JSON SELECT * FROM t1 WHERE f > '00:01:00'; |
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SET histogram_type= DOUBLE_PREC_HB; |
ANALYZE TABLE t1 PERSISTENT FOR ALL; |
ANALYZE FORMAT=JSON SELECT * FROM t1 WHERE f > '00:01:00'; |
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DROP TABLE t1; |
JSON_HB:
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preview-10.8-MDEV-26519-json-histograms da3231a8 |
"table": {
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"table_name": "t1",
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"access_type": "ALL",
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"r_loops": 1,
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"rows": 1000,
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"r_rows": 1000,
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"r_table_time_ms": 0.037146099,
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"r_other_time_ms": 0.077310006,
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"filtered": 99.75002289,
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"r_filtered": 50,
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"attached_condition": "t1.f > '00:01:00'"
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}
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DOUBLE_PREC_HB:
"table": {
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"table_name": "t1",
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"access_type": "ALL",
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"r_loops": 1,
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"rows": 1000,
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"r_rows": 1000,
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"r_table_time_ms": 0.033997955,
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"r_other_time_ms": 0.07762081,
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"filtered": 50,
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"r_filtered": 50,
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"attached_condition": "t1.f > '00:01:00'"
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}
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Attachments
Issue Links
- is caused by
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MDEV-26519 JSON Histograms: improve histogram collection
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- Closed
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