[store] refactor: remove MetaStore::{open,new}, open_create() is enough

[drmingdrmer]

I hereby agree to the terms of the CLA available at: https://datafuse.rs/policies/cla/

Summary

[store] refactor: remove MetaStore::{open,new}, open_create() is enough

[store] refactor: rename SledVarTypeTree::as_type to key_space

[store] refactor: remove dup impl: StateMachine::get_node() is provided by impl Placement

Changelog

• Improvement

Related Issues

• FuseStore v0.1  #271

[databend-bot]

Thanks for the contribution!
I have applied any labels matching special text in your PR Changelog.

Please review the labels and make any necessary changes.

[databend-bot]

Thanks for the contribution!
I have applied any labels matching special text in your PR Changelog.

Please review the labels and make any necessary changes.

[databend-bot]

Thanks for the contribution!
I have applied any labels matching special text in your PR Changelog.

Please review the labels and make any necessary changes.

[databend-bot]

Thanks for the contribution!
I have applied any labels matching special text in your PR Changelog.

Please review the labels and make any necessary changes.

[codecov-commenter]

Codecov Report

Merging #1331 (fffb9c1) into master (ae39181) will decrease coverage by 0%.
The diff coverage is 94%.

@@          Coverage Diff           @@
##           master   #1331   +/-   ##
======================================
- Coverage      72%     72%   -1%     
======================================
  Files         481     481           
  Lines       28021   28013    -8     
======================================
- Hits        20301   20292    -9     
- Misses       7720    7721    +1     

Impacted Files	Coverage Δ
fusestore/store/src/meta_service/placement.rs	38% <0%> (ø)
...store/store/src/meta_service/state_machine_test.rs	89% <ø> (ø)
fusestore/store/src/meta_service/raftmeta.rs	77% <33%> (-1%)	⬇️
fusestore/store/src/meta_service/state_machine.rs	76% <77%> (+<1%)	⬆️
...usestore/store/src/meta_service/meta_store_test.rs	96% <100%> (+<1%)	⬆️
fusestore/store/src/meta_service/raft_log.rs	90% <100%> (ø)
...estore/store/src/meta_service/sled_vartype_tree.rs	92% <100%> (ø)
...e/store/src/meta_service/sled_vartype_tree_test.rs	97% <100%> (ø)

---

Continue to review full report at Codecov.

Legend - Click here to learn more
Δ = absolute <relative> (impact), ø = not affected, ? = missing data
Powered by Codecov. Last update ae39181...fffb9c1. Read the comment docs.

[databend-bot]

CI Passed
Reviewer Approved
Let's Merge