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https://issues.apache.org/jira/browse/HIVE-23095?focusedWorklogId=418477&page=com.atlassian.jira.plugin.system.issuetabpanels:worklog-tabpanel#worklog-418477
]
ASF GitHub Bot logged work on HIVE-23095:
-----------------------------------------
Author: ASF GitHub Bot
Created on: 08/Apr/20 12:22
Start Date: 08/Apr/20 12:22
Worklog Time Spent: 10m
Work Description: kgyrtkirk commented on pull request #964: HIVE-23095
ndv 70
URL: https://github.com/apache/hive/pull/964#discussion_r405482181
##########
File path:
standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/common/ndv/hll/HLLSparseRegister.java
##########
@@ -148,8 +148,12 @@ public int encodeHash(long hashcode) {
}
}
- public int getSize() {
- return sparseMap.size() + tempListIdx;
+ public boolean isSizeGreaterThan(int s) {
+ if (sparseMap.size() + tempListIdx > s) {
+ mergeTempListToSparseMap();
Review comment:
we are using:
* sizeOptimized => p=10
* bitpacking is enabled by default
formula to count the threshold in this case is:
```
2**p * 6/8/5 = ~150
```
https://github.com/apache/hive/blob/d91cc0cd84b7d0ecc0f29d44b109b46e21194eec/standalone-metastore/metastore-server/src/main/java/org/apache/hadoop/hive/common/ndv/hll/HyperLogLog.java#L116
I also found that a little too few...but that's what it is...
all changes are here; this conversation is on a diff which is "outdated"
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Issue Time Tracking
-------------------
Worklog Id: (was: 418477)
Time Spent: 50m (was: 40m)
> NDV might be overestimated for a table with ~70 value
> -----------------------------------------------------
>
> Key: HIVE-23095
> URL: https://issues.apache.org/jira/browse/HIVE-23095
> Project: Hive
> Issue Type: Bug
> Reporter: Zoltan Haindrich
> Assignee: Zoltan Haindrich
> Priority: Major
> Labels: pull-request-available
> Attachments: HIVE-23095.01.patch, HIVE-23095.02.patch,
> HIVE-23095.03.patch, HIVE-23095.04.patch, HIVE-23095.04.patch,
> HIVE-23095.04.patch, HIVE-23095.05.patch, hll-bench.md
>
> Time Spent: 50m
> Remaining Estimate: 0h
>
> uncovered during looking into HIVE-23082
> https://issues.apache.org/jira/browse/HIVE-23082?focusedCommentId=17067773&page=com.atlassian.jira.plugin.system.issuetabpanels%3Acomment-tabpanel#comment-17067773
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