Fix replication tree with sharding

[samuelmanzanera]

Description

This PR aims to resolve a problem of serialization when the size of the replication tree is different from the chain replicas & beacon replicas

Fixes #663

Type of change

• Bug fix (non-breaking change which fixes an issue)

How Has This Been Tested?

You can apply this patch, with more than 5 running nodes

diff --git a/lib/archethic/election/constraints/storage.ex b/lib/archethic/election/constraints/storage.ex
index 02ed0edc..7f8fb879 100755
--- a/lib/archethic/election/constraints/storage.ex
+++ b/lib/archethic/election/constraints/storage.ex
@@ -13,8 +13,8 @@ defmodule Archethic.Election.StorageConstraints do
 
   alias Archethic.P2P.Node
 
-  @default_min_geo_patch 4
-  @default_min_geo_patch_avg_availability 0.8
+  @default_min_geo_patch 1
+  @default_min_geo_patch_avg_availability 0.0
 
   @type min_geo_patch_fun() :: (() -> non_neg_integer())
   @type min_geo_patch_avg_availability_fun() :: (() -> float())
@@ -108,9 +108,14 @@ defmodule Archethic.Election.StorageConstraints do
   """
   @spec hypergeometric_distribution(list(Node.t())) :: pos_integer()
   def hypergeometric_distribution(nodes)
-      when is_list(nodes) and length(nodes) >= 0 and length(nodes) <= 10,
-      do: nodes
+      when is_list(nodes) and length(nodes) >= 0 and length(nodes) <= 10 do
+    if length(nodes) > 5 do
+      length(nodes) - 2
+    else
+      length(nodes)
+    end
+  end
 
-  def hypergeometric_distribution(nodes) when is_list(nodes) and length(nodes) >= 0,
+  def hypergeometric_distribution(nodes) when is_list(nodes),
     do: HypergeometricDistribution.run_simulation(length(nodes))
 end

Checklist:

• My code follows the style guidelines of this project
• I have performed a self-review of my own code
• I have commented my code, particularly in hard-to-understand areas
• I have made corresponding changes to the documentation
• My changes generate no new warnings
• I have added tests that prove my fix is effective or that my feature works
• New and existing unit tests pass locally with my changes
• Any dependent changes have been merged and published in downstream modules

[apoorv-2204]

How to ?

[apoorv-2204]

@default_min_geo_patch_avg_availability 0.0?

[apoorv-2204]

(develop branch latest commit -1) code + 5 Nodes + mix dev.lbench + Archethic.Utils.Regression.Benchmark.EndToEndValidation.plan(["127.0.0.1"],[]) + git patch
serialization errors

No serialization error, seen with
(develop branch latest commit -1) code + prcode+ 5 Nodes + mix dev.lbench + Archethic.Utils.Regression.Benchmark.EndToEndValidation.plan(["127.0.0.1"],[]) + git patch

Unit Test cases is required.

[samuelmanzanera]

@default_min_geo_patch_avg_availability 0.0?

This is used to say we don't expect minimal availability ratio per geo patch.

[apoorv-2204]

Can we include dynamic creation of replication tree?

[samuelmanzanera]

What do you mean ?

[Neylix]

In storage constraint if the number of nodes is between 0 and 10 we are returning the list of nodes instead of the number of nodes

archethic-node/lib/archethic/election/constraints/storage.ex

Line 112 in 438d66e

do: nodes

[samuelmanzanera]

In storage constraint if the number of nodes is between 0 and 10 we are returning the list of nodes instead of the number of nodes

archethic-node/lib/archethic/election/constraints/storage.ex

Line 112 in 438d66e

do: nodes

Yes indeed , to do like in the patch