diff --git a/src/Clp.jl b/src/Clp.jl
index 0086741..9ea0b55 100644
--- a/src/Clp.jl
+++ b/src/Clp.jl
@@ -29,6 +29,10 @@ end
 
 include("MOI_wrapper/MOI_wrapper.jl")
 
+if VERSION > v"1.4.2"
+    include("precompile.jl")
+end
+
 # TODO(odow): remove at Clp.jl v1.0.0.
 function ClpSolver(args...; kwargs...)
     error(
diff --git a/src/MOI_wrapper/MOI_wrapper.jl b/src/MOI_wrapper/MOI_wrapper.jl
index 677dc44..4fa5f45 100644
--- a/src/MOI_wrapper/MOI_wrapper.jl
+++ b/src/MOI_wrapper/MOI_wrapper.jl
@@ -266,9 +266,10 @@ function _index_map(
     ::Type{F},
     ::Type{S},
 ) where {F,S}
+    inner = index_map.con_map[F, S]
     for ci in MOI.get(src, MOI.ListOfConstraintIndices{F,S}())
         row = MOI.Utilities.rows(src.constraints, ci)
-        index_map[ci] = MOI.ConstraintIndex{F,S}(row)
+        inner[ci] = MOI.ConstraintIndex{F,S}(row)
     end
     return
 end
@@ -279,9 +280,10 @@ function _index_map(
     F::Type{MOI.VariableIndex},
     ::Type{S},
 ) where {S}
+    inner = index_map.con_map[F, S]
     for ci in MOI.get(src, MOI.ListOfConstraintIndices{F,S}())
         col = index_map[MOI.VariableIndex(ci.value)].value
-        index_map[ci] = MOI.ConstraintIndex{F,S}(col)
+        inner[ci] = MOI.ConstraintIndex{F,S}(col)
     end
     return
 end
diff --git a/src/precompile.jl b/src/precompile.jl
new file mode 100644
index 0000000..237c0d7
--- /dev/null
+++ b/src/precompile.jl
@@ -0,0 +1,16 @@
+function warmup()
+    bridge = MOI.instantiate(Optimizer; with_bridge_type=Float64)
+    no_bridge = MOI.instantiate(Optimizer)
+    cache = MOI.Utilities.UniversalFallback(MOI.Utilities.Model{Float64}())
+    MOI.optimize!(bridge, cache)
+    MOI.optimize!(no_bridge, cache)
+    return
+end
+
+function _precompile_()
+    ccall(:jl_generating_output, Cint, ()) == 1 || return nothing
+    precompile(warmup, ())
+    return
+end
+
+_precompile_()