[CARBONDATA-4105] Select * query fails after a SDK written segment is added by alter table add segment query.

• Type: Bug
• Status: Closed
• Priority: Major
• Resolution: Not A Bug
• Component/s: core
• Assignee: Unassigned
• Reporter: Karan
• Created: 11/Jan/21 18:38
• Updated: 20/Jan/21 12:17
• Resolved: 20/Jan/21 12:17

Description

When a SDK written segment on which read is already performed once, is added through alter table add segment query to a carbon table, then select * query fails after adding it.

In SDK segments the segmentId is the timestamp of the segment. When the SDK segment is read before adding, its indexes are stored in cache. Cache is a map of indexFilePath to Indexes. Now when the same segment is added to carbon table its segment ID is no longer the timestamp but the indexFilePath remains same as it is added externally. Now when we run select * query we get the indexes from the cache, but it is unable to map it to segment, because segment id changes.