fix(db): add additional connection pool for projection spooling (#7094)

* fix(db): add additional connection pool for projection spooling

* use correct connection pool for projections

---------

Co-authored-by: Livio Spring <livio.a@gmail.com>

(cherry picked from commit fe1337536f)

internal/database/dialect/connections_test.go

@@ -0,0 +1,252 @@
+package dialect
+
+import (
+	"testing"
+
+	"github.com/stretchr/testify/assert"
+	"github.com/stretchr/testify/require"
+)
+
+func TestConnectionConfig_takeRatio(t *testing.T) {
+	type fields struct {
+		MaxOpenConns uint32
+		MaxIdleConns uint32
+	}
+	tests := []struct {
+		name    string
+		fields  fields
+		ratio   float64
+		wantOut *ConnectionConfig
+		wantErr error
+	}{
+		{
+			name:    "ratio less than 0 error",
+			ratio:   -0.1,
+			wantErr: ErrNegativeRatio,
+		},
+		{
+			name: "zero values",
+			fields: fields{
+				MaxOpenConns: 0,
+				MaxIdleConns: 0,
+			},
+			ratio: 0,
+			wantOut: &ConnectionConfig{
+				MaxOpenConns: 0,
+				MaxIdleConns: 0,
+			},
+		},
+		{
+			name: "max conns, ratio 0",
+			fields: fields{
+				MaxOpenConns: 10,
+				MaxIdleConns: 5,
+			},
+			ratio: 0,
+			wantOut: &ConnectionConfig{
+				MaxOpenConns: 0,
+				MaxIdleConns: 0,
+			},
+		},
+		{
+			name: "half ratio",
+			fields: fields{
+				MaxOpenConns: 10,
+				MaxIdleConns: 5,
+			},
+			ratio: 0.5,
+			wantOut: &ConnectionConfig{
+				MaxOpenConns: 5,
+				MaxIdleConns: 2,
+			},
+		},
+		{
+			name: "minimal 1",
+			fields: fields{
+				MaxOpenConns: 2,
+				MaxIdleConns: 2,
+			},
+			ratio: 0.1,
+			wantOut: &ConnectionConfig{
+				MaxOpenConns: 1,
+				MaxIdleConns: 1,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			in := &ConnectionConfig{
+				MaxOpenConns: tt.fields.MaxOpenConns,
+				MaxIdleConns: tt.fields.MaxIdleConns,
+			}
+			got, err := in.takeRatio(tt.ratio)
+			require.ErrorIs(t, err, tt.wantErr)
+			assert.Equal(t, tt.wantOut, got)
+		})
+	}
+}
+
+func TestNewConnectionConfig(t *testing.T) {
+	type args struct {
+		openConns       uint32
+		idleConns       uint32
+		pusherRatio     float64
+		projectionRatio float64
+		purpose         DBPurpose
+	}
+	tests := []struct {
+		name    string
+		args    args
+		want    *ConnectionConfig
+		wantErr error
+	}{
+		{
+			name: "illegal open conns error",
+			args: args{
+				openConns: 2,
+				idleConns: 3,
+			},
+			wantErr: ErrIllegalMaxOpenConns,
+		},
+		{
+			name: "illegal idle conns error",
+			args: args{
+				openConns: 3,
+				idleConns: 2,
+			},
+			wantErr: ErrIllegalMaxIdleConns,
+		},
+		{
+			name: "high ration sum error",
+			args: args{
+				openConns:       3,
+				idleConns:       3,
+				pusherRatio:     0.5,
+				projectionRatio: 0.5,
+			},
+			wantErr: ErrHighSumRatio,
+		},
+		{
+			name: "illegal pusher ratio error",
+			args: args{
+				openConns:       3,
+				idleConns:       3,
+				pusherRatio:     -0.1,
+				projectionRatio: 0.5,
+			},
+			wantErr: ErrNegativeRatio,
+		},
+		{
+			name: "illegal projection ratio error",
+			args: args{
+				openConns:       3,
+				idleConns:       3,
+				pusherRatio:     0.5,
+				projectionRatio: -0.1,
+			},
+			wantErr: ErrNegativeRatio,
+		},
+		{
+			name: "invalid purpose error",
+			args: args{
+				openConns:       3,
+				idleConns:       3,
+				pusherRatio:     0.4,
+				projectionRatio: 0.4,
+				purpose:         99,
+			},
+			wantErr: ErrInvalidPurpose,
+		},
+		{
+			name: "min values, query purpose",
+			args: args{
+				openConns:       3,
+				idleConns:       3,
+				pusherRatio:     0.2,
+				projectionRatio: 0.2,
+				purpose:         DBPurposeQuery,
+			},
+			want: &ConnectionConfig{
+				MaxOpenConns: 1,
+				MaxIdleConns: 1,
+			},
+		},
+		{
+			name: "min values, pusher purpose",
+			args: args{
+				openConns:       3,
+				idleConns:       3,
+				pusherRatio:     0.2,
+				projectionRatio: 0.2,
+				purpose:         DBPurposeEventPusher,
+			},
+			want: &ConnectionConfig{
+				MaxOpenConns: 1,
+				MaxIdleConns: 1,
+			},
+		},
+		{
+			name: "min values, projection purpose",
+			args: args{
+				openConns:       3,
+				idleConns:       3,
+				pusherRatio:     0.2,
+				projectionRatio: 0.2,
+				purpose:         DBPurposeProjectionSpooler,
+			},
+			want: &ConnectionConfig{
+				MaxOpenConns: 1,
+				MaxIdleConns: 1,
+			},
+		},
+		{
+			name: "high values, query purpose",
+			args: args{
+				openConns:       10,
+				idleConns:       5,
+				pusherRatio:     0.2,
+				projectionRatio: 0.2,
+				purpose:         DBPurposeQuery,
+			},
+			want: &ConnectionConfig{
+				MaxOpenConns: 6,
+				MaxIdleConns: 3,
+			},
+		},
+		{
+			name: "high values, pusher purpose",
+			args: args{
+				openConns:       10,
+				idleConns:       5,
+				pusherRatio:     0.2,
+				projectionRatio: 0.2,
+				purpose:         DBPurposeEventPusher,
+			},
+			want: &ConnectionConfig{
+				MaxOpenConns: 2,
+				MaxIdleConns: 1,
+			},
+		},
+		{
+			name: "high values, projection purpose",
+			args: args{
+				openConns:       10,
+				idleConns:       5,
+				pusherRatio:     0.2,
+				projectionRatio: 0.2,
+				purpose:         DBPurposeProjectionSpooler,
+			},
+			want: &ConnectionConfig{
+				MaxOpenConns: 2,
+				MaxIdleConns: 1,
+			},
+		},
+	}
+	for _, tt := range tests {
+		t.Run(tt.name, func(t *testing.T) {
+			got, err := NewConnectionConfig(tt.args.openConns, tt.args.idleConns, tt.args.pusherRatio, tt.args.projectionRatio, tt.args.purpose)
+			require.ErrorIs(t, err, tt.wantErr)
+			assert.Equal(t, tt.want, got)
+		})
+	}
+}