quick fix for the subgraph creation deadlock

[ljeub-pometry]

What changes were proposed in this pull request?

Fix deadlock in the server when creating a subgraph for a graph that is not currently in the cache.

Does this PR introduce any user-facing change? If yes is this documented?

No

How was this patch tested?

Added test that reproduced the deadlock

Are there any further changes required?

We need to review the mutation locking and dirty path cleanup logic. The root cause is that the read path currently also has to acquire the read lock for the mutations as it cleans up dirty paths.

[github-actions]

⚠️ Performance Alert ⚠️

Possible performance regression was detected for benchmark 'Rust Benchmark'.
Benchmark result of this commit is worse than the previous benchmark result exceeding threshold 2.

Benchmark suite	Current: b5a9cad	Previous: 9823ef7	Ratio
lotr_graph/num_edges	6 ns/iter (± 0)	0 ns/iter (± 0)	+∞
lotr_graph/num_nodes	6 ns/iter (± 0)	1 ns/iter (± 0)	6
lotr_graph/graph_latest	3 ns/iter (± 0)	0 ns/iter (± 0)	+∞
lotr_graph_materialise/materialize	7809859 ns/iter (± 27070)	1564816 ns/iter (± 35303)	4.99
lotr_graph_window_100/num_nodes	18 ns/iter (± 0)	5 ns/iter (± 0)	3.60
lotr_graph_window_100_materialise/materialize	7900219 ns/iter (± 56689)	1669150 ns/iter (± 10700)	4.73
lotr_graph_window_10/has_node_existing	140 ns/iter (± 9)	62 ns/iter (± 11)	2.26
lotr_graph_window_10_materialise/materialize	3428068 ns/iter (± 10750)	971980 ns/iter (± 4278)	3.53
lotr_graph_subgraph_10pc/has_node_nonexisting	5 ns/iter (± 0)	2 ns/iter (± 0)	2.50
lotr_graph_subgraph_10pc_materialise/materialize	2313372 ns/iter (± 24555)	334634 ns/iter (± 1287)	6.91
lotr_graph_subgraph_10pc_windowed/has_node_existing	145 ns/iter (± 8)	62 ns/iter (± 14)	2.34
lotr_graph_subgraph_10pc_windowed_materialise/materialize	1524992 ns/iter (± 11460)	230399 ns/iter (± 2617)	6.62
lotr_graph_window_50_layered/num_edges_temporal	147589 ns/iter (± 1761)	70121 ns/iter (± 7586)	2.10
lotr_graph_window_50_layered/has_node_existing	396 ns/iter (± 19)	129 ns/iter (± 12)	3.07
lotr_graph_window_50_layered/graph_latest	89281 ns/iter (± 1924)	36649 ns/iter (± 916)	2.44
lotr_graph_window_50_layered_materialise/materialize	30340739 ns/iter (± 166729)	3488825 ns/iter (± 24948)	8.70
lotr_graph_persistent_window_50_layered/num_edges_temporal	593299 ns/iter (± 4291)	192686 ns/iter (± 1569)	3.08
lotr_graph_persistent_window_50_layered/has_node_existing	414 ns/iter (± 383)	174 ns/iter (± 83)	2.38
lotr_graph_persistent_window_50_layered/graph_latest	133982 ns/iter (± 2087)	57549 ns/iter (± 4809)	2.33
lotr_graph_persistent_window_50_layered_materialise/materialize	52094159 ns/iter (± 150583)	5298035 ns/iter (± 147912)	9.83

This comment was automatically generated by workflow using github-action-benchmark.