[IGNITE-7027] SQL: Single primary index instead of mulitple per-partition indexes

• Type: Task
• Status: Closed
• Priority: Major
• Resolution: Won't Fix
• Component/s: cache, sql
• Labels: performance
• Assignee: Unassigned
• Reporter: Vladimir Ozerov
• Created: 27/Nov/17 20:43
• Updated: 14/Feb/19 15:18
• Resolved: 14/Feb/19 15:16

Description

Currently we have per-partition primary index. This gives us easy and effective rebalance/recovery capabilities and efficient lookup in key-value mode.

However, this doesn't work well for SQL case. We cannot use this index for range scans. Neither we can use it for PK lookups (it is possible to implement, but will be less then optimal due to necessity to build the whole key object).

The following change is suggested as optional storage mode:
1) Single index data structure for all partitions
2) Only single key type is allowed (i.e. no mess in the cache and no cache groups)
3) Additional SQL PK index will not be needed in this case

Advantage:

• No overhead on the second PK index

Disadvantage:

• Less efficient rebalance and recovery