diff --git a/src/searchgraph/neighborhood.jl b/src/searchgraph/neighborhood.jl
index 9f49a62..b6751be 100644
--- a/src/searchgraph/neighborhood.jl
+++ b/src/searchgraph/neighborhood.jl
@@ -18,8 +18,7 @@ Base.copy(N::Neighborhood;
         filter=copy(N.filter)
     ) = Neighborhood(; logbase, minsize, filter)
 
-function neighborhoodsize(N::Neighborhood, index::SearchGraph)::Int
-    n = length(index)
+function neighborhoodsize(N::Neighborhood, n::Integer)::Int
     n == 0 ? 0 : ceil(Int, N.minsize + log(N.logbase, n))
 end
 
@@ -39,7 +38,7 @@ the given context.
 """
 function find_neighborhood(copy_::Function, index::SearchGraph, context::SearchGraphContext, item; hints=index.hints)
     neighborhood = context.neighborhood
-    ksearch = neighborhoodsize(neighborhood, index)
+    ksearch = neighborhoodsize(neighborhood, length(index))
     res = getknnresult(ksearch, context)
     if ksearch > 0
         search(index.algo, index, context, item, res, hints)
diff --git a/src/searchgraph/optbs.jl b/src/searchgraph/optbs.jl
index 547c1c8..3365f58 100644
--- a/src/searchgraph/optbs.jl
+++ b/src/searchgraph/optbs.jl
@@ -96,8 +96,7 @@ function setconfig!(bs::BeamSearch, index::SearchGraph, perf)
 end
 
 function runconfig(bs::BeamSearch, index::SearchGraph, ctx::SearchGraphContext, q, res::KnnResult)
-    search(bs, index, ctx, q, res, index.hints; maxvisits = 4index.algo.maxvisits)
-    # search(bs, index, q, res, index.hints, caches)
+    search(bs, index, ctx, q, res, index.hints; maxvisits = 2index.algo.maxvisits)
 end
 
 """
@@ -107,6 +106,12 @@ SearchGraph's callback for adjunting search parameters
 """
 function execute_callback(index::SearchGraph, context::SearchGraphContext, opt::OptimizeParameters)
     queries = nothing
-    optimize_index!(index, context, opt.kind; opt.space,
-        queries, opt.ksearch, opt.numqueries, opt.initialpopulation, opt.verbose, opt.params)
+    optimize_index!(index, context, opt.kind;
+                    opt.space,
+                    queries,
+                    ksearch=neighborhoodsize(context.neighborhood, length(index)),
+                    opt.numqueries,
+                    opt.initialpopulation,
+                    opt.verbose,
+                    opt.params)
 end
diff --git a/test/testsearchgraph.jl b/test/testsearchgraph.jl
index e1d09fd..28f3f1d 100644
--- a/test/testsearchgraph.jl
+++ b/test/testsearchgraph.jl
@@ -94,7 +94,7 @@ end
     )
     index!(graph, ctx)
     @test n == length(db) == length(graph)
-    optimize_index!(graph, ctx, MinRecall(0.9); queries)
+    optimize_index!(graph, ctx, MinRecall(0.9); queries, ksearch)
     searchtime = @elapsed I, D = searchbatch(graph, ctx, queries, ksearch)
     @test size(I) == size(D) == (ksearch, m) == size(goldI)
     recall = macrorecall(goldI, I)