support sstoragePisa.RemoveKVData

[cyl19970726]

No description provided.

[cyl19970726]

The remove operation consists of two steps.

• First, replace the data corresponding to removeKvIdx selected by the operator with data of lastKvIdx
• Second, set the data space of the original lastKvIdx to 0

Test

• Tests are written in the contracts_test.go file.
• I prepare three shards to test.
  • Shard Info : MaxKvEntries = 10; KVSize = 4 * 1024; chunksPerKv = 1; ChunkSize = 4 *1024
• Test case cover:
  • put
    • put test: the operation of storing data will fill up all shards
  • update
    • update test : the operation of updating data will update all data stored in each shard
  • remove
    • remove test:
      • case 1: removeKvIdx is equal to lastKvIdx
      • case 2: removeKvIdx and lastKvIdx are in the same Shard
      • case 3: removeKvIdx and lastKvIdx are in the different Shard

[qizhou]

What if the replaceData does not exist locally?

[qizhou]

TWP Section 5.3 has a discussion on this https://galileo.web3q.io/file.w3q/0x67d0481cc9c2e9dad2987e58a365aae977dcb8da/dynamic_data_sharding_0_1_6.pdf

[cyl19970726]

I took an approach that only allows deletion of KV entries in the last shard

[blockchaindevsh]

What will happen in this case: the shard is still synchronizing, so the SstorageRead may be stale. If we move the last kv into a kv index past synchronizing, the stale data will be there forever. If we add verification logic when SstorageRead, we can't even guarantee the execution result is the same across nodes.