diff --git a/lib/common/path-set.ts b/lib/common/path-set.ts
index 4edad4c..10bb564 100644
--- a/lib/common/path-set.ts
+++ b/lib/common/path-set.ts
@@ -22,10 +22,12 @@ import Path from "./path";
 export default class PathSet {
   private lengthIndex: Set<Path>[];
   private fragmentIndex: Map<string, Set<Path>>[];
+  private stringIndex: Map<string, Path>;
 
   public constructor() {
     this.lengthIndex = [];
     this.fragmentIndex = [];
+    this.stringIndex = new Map();
   }
 
   public get depth(): number {
@@ -38,9 +40,12 @@ export default class PathSet {
 
     if (p) return p;
 
+    this.stringIndex.set(path.toString(), path);
+
     while (this.lengthIndex.length <= path.length) {
       this.lengthIndex.push(new Set());
-      this.fragmentIndex.push(new Map());
+      // fragmentIndex is one less than lengthIndex
+      if (this.lengthIndex.length > 1) this.fragmentIndex.push(new Map());
     }
 
     const lengthIndex = this.lengthIndex[path.length];
@@ -63,41 +68,7 @@ export default class PathSet {
   }
 
   public get(path: Path): Path {
-    if (path.alias) throw new Error("PathSet does not support aliased paths");
-    const lengthIndex = this.lengthIndex[path.length];
-    if (!lengthIndex || !lengthIndex.size) return null;
-
-    if (lengthIndex.has(path)) return path;
-
-    const sets = [lengthIndex];
-
-    for (let i = 0; i < path.length; ++i) {
-      const fragmentIndex = this.fragmentIndex[i];
-      if (!fragmentIndex || !fragmentIndex.size) return null;
-
-      const fragment = path.segments[i] as string;
-
-      const fragmentIndexSet = fragmentIndex.get(fragment);
-      if (!fragmentIndexSet) return null;
-
-      sets.push(fragmentIndexSet);
-    }
-
-    sets.sort((a, b) => a.size - b.size);
-
-    const smallestSet = sets.shift();
-    for (let p of smallestSet) {
-      for (const s of sets) {
-        if (!s.has(p)) {
-          p = null;
-          break;
-        }
-      }
-
-      if (p) return p;
-    }
-
-    return null;
+    return this.stringIndex.get(path.toString()) || null;
   }
 
   public find(
@@ -107,61 +78,53 @@ export default class PathSet {
     depth: number = path.length
   ): Path[] {
     if (path.alias) throw new Error("PathSet does not support aliased paths");
-    const res = [];
-    const groups = [[]];
 
-    for (let i = path.length; i <= depth; ++i)
-      if (this.lengthIndex[i]) groups[0].push(this.lengthIndex[i]);
+    const len = path.length;
 
-    if (!groups[0].length) return res;
+    if (!superset && depth === len && (!subset || !path.wildcard)) {
+      const p = this.get(path);
+      return p ? [p] : [];
+    }
 
-    for (let i = 0; i < path.length; ++i) {
+    const lengthIndex = this.lengthIndex.slice(len, depth + 1);
+    if (!lengthIndex.length) return [];
+
+    let res;
+    for (let i = len - 1; i >= 0; --i) {
+      let fragmentIndexSet2;
       const fragmentIndex = this.fragmentIndex[i];
-      if (!fragmentIndex) return res;
+
+      if ((path.wildcard >> i) & 1) {
+        if (subset) continue;
+      } else if (superset) {
+        fragmentIndexSet2 = fragmentIndex.get("*");
+      }
 
       const fragment = path.segments[i] as string;
+      const fragmentIndexSet1 = fragmentIndex.get(fragment);
 
-      if (fragment === "*" && subset) continue;
-
-      const g = [];
-
-      const s = fragmentIndex.get(fragment);
-      if (s) g.push(s);
-
-      if (fragment !== "*" && superset && fragmentIndex.has("*"))
-        g.push(fragmentIndex.get("*"));
-
-      if (!g.length) return res;
-
-      groups.push(g);
-    }
-
-    groups.sort(
-      (a, b) =>
-        a.reduce((prev, cur) => prev + cur.size, 0) -
-        b.reduce((prev, cur) => prev + cur.size, 0)
-    );
-
-    const smallestGroup = groups.shift();
-    for (const set of smallestGroup) {
-      for (let p of set) {
-        for (const group of groups) {
-          let found = false;
-          for (const s of group) {
-            if (s.has(p)) {
-              found = true;
-              break;
-            }
-          }
-
-          if (!found) {
-            p = null;
-            break;
-          }
+      if (!fragmentIndexSet1) {
+        if (!fragmentIndexSet2) return [];
+        if (!res) res = [...fragmentIndexSet2];
+        else res = res.filter(r => fragmentIndexSet2.has(r));
+      } else if (!fragmentIndexSet2) {
+        if (!res) res = [...fragmentIndexSet1];
+        else res = res.filter(r => fragmentIndexSet1.has(r));
+      } else {
+        if (!res) {
+          res = [...fragmentIndexSet1, ...fragmentIndexSet2];
+        } else {
+          res = res.filter(
+            r => fragmentIndexSet1.has(r) || fragmentIndexSet2.has(r)
+          );
         }
-        if (p) res.push(p);
       }
+      if (!res.length) return res;
     }
+
+    if (!res) res = [].concat(...lengthIndex.map(a => [...a]));
+    else res = res.filter(r => lengthIndex.some(a => a.has(r)));
+
     return res;
   }
 }
diff --git a/lib/common/path.ts b/lib/common/path.ts
index 60fd16f..e13413c 100644
--- a/lib/common/path.ts
+++ b/lib/common/path.ts
@@ -28,6 +28,7 @@ export default class Path {
   public readonly wildcard: number;
   public readonly alias: number;
   protected _string: string;
+  protected _stringIndex: number[];
 
   protected static parseAlias(
     pattern: string,
@@ -35,8 +36,8 @@ export default class Path {
   ): { index: number; alias: Alias } {
     const alias: Alias = [];
     while (index < pattern.length && pattern[index] !== "]") {
-      const res = Path.parsePath(pattern, index);
-      let j = (index = res.index + 1);
+      const { index: idx, segments } = Path.parsePath(pattern, index);
+      let j = (index = idx + 1);
       while (pattern[j] !== "]" && pattern[j] !== ",") {
         if (pattern[j] === '"' && index === j) {
           ++j;
@@ -58,7 +59,7 @@ export default class Path {
         }
       }
 
-      alias.push([new Path(res.segments, res.wildcard, res.alias), value]);
+      alias.push([new Path(segments), value]);
       if (pattern[index] === ",") ++index;
     }
 
@@ -78,18 +79,15 @@ export default class Path {
   protected static parsePath(
     pattern: string,
     index: number
-  ): { index: number; segments: Segments; wildcard: number; alias: number } {
+  ): { index: number; segments: Segments } {
     const segments = [];
-    let wildcard = 0;
-    let alias = 0;
     // Colon separator is needed for parseAlias
     if (index < pattern.length && pattern[index] !== ":") {
       for (;;) {
         if (pattern[index] === "[") {
-          const res = Path.parseAlias(pattern, index + 1);
-          index = res.index + 1;
-          alias |= 1 << segments.length;
-          segments.push(res.alias);
+          const { index: idx, alias } = Path.parseAlias(pattern, index + 1);
+          index = idx + 1;
+          segments.push(alias);
         } else {
           const j = index;
           while (
@@ -99,7 +97,6 @@ export default class Path {
           )
             ++index;
           const s = pattern.slice(j, index).trim();
-          if (s === "*") wildcard |= 1 << segments.length;
           segments.push(s);
         }
 
@@ -111,14 +108,33 @@ export default class Path {
     }
 
     Object.freeze(segments);
-    return { index, segments, wildcard, alias };
+    return { index, segments };
   }
 
-  protected constructor(segments: Segments, wildcard: number, alias: number) {
+  protected constructor(segments: Segments) {
+    let alias = 0;
+    let wildcard = 0;
+    const arr = segments.map((s, i) => {
+      if (Array.isArray(s)) {
+        alias |= 1 << i;
+        const parts = s.map(
+          al => `${al[0].toString()}:${JSON.stringify(al[1])}`
+        );
+        return `[${parts.join(",")}]`;
+      } else if (s === "*") {
+        wildcard |= 1 << i;
+      }
+      return s;
+    });
+
+    let offset = 0;
+    const stringIndex = arr.map((s, i) => (offset += s.length) + i);
+
     this.segments = segments;
     this.wildcard = wildcard;
     this.alias = alias;
-    this._string = null;
+    this._string = arr.join(".");
+    this._stringIndex = stringIndex;
   }
 
   public static parse(str: string): Path {
@@ -126,8 +142,9 @@ export default class Path {
     if (!path) {
       path = cache2.get(str);
       if (!path) {
-        const res = Path.parsePath(str, 0);
-        path = new Path(res.segments, res.wildcard, res.alias);
+        const { segments } = Path.parsePath(str, 0);
+        path = new Path(segments);
+        if (path.toString() !== str) cache1.set(path.toString(), path);
       }
       cache1.set(str, path);
     }
@@ -139,44 +156,75 @@ export default class Path {
   }
 
   public toString(): string {
-    if (this._string == null) {
-      this._string = this.segments
-        .map(s => {
-          if (Array.isArray(s)) {
-            const parts = s.map(
-              al => `${al[0].toString()}:${JSON.stringify(al[1])}`
-            );
-            return `[${parts.join(",")}]`;
-          }
-          return s;
-        })
-        .join(".");
-    }
     return this._string;
   }
 
   public slice(start: number = 0, end: number = this.segments.length): Path {
     if (start < 0) start = Math.max(0, this.segments.length + start);
     if (end < 0) end = Math.max(0, this.segments.length + end);
-    if (start >= end) return new Path([], 0, 0);
-    const segments = this.segments.slice(start, end);
-    const mask = (1 << (end - start)) - 1;
-    const wildcard = (this.wildcard >> start) & mask;
-    const alias = (this.alias >> start) & mask;
-    return new Path(segments, wildcard, alias);
+
+    let str;
+    if (start >= end) {
+      str = "";
+    } else {
+      const i1 = start > 0 ? this._stringIndex[start - 1] + 1 : 0;
+      const i2 =
+        end <= this.segments.length
+          ? this._stringIndex[end - 1]
+          : this._string.length;
+      str = this._string.slice(i1, i2);
+    }
+
+    let path = cache1.get(str);
+    if (!path) {
+      path = cache2.get(str);
+      if (!path) {
+        const segments = this.segments.slice(start, end);
+        Object.freeze(segments);
+        path = new Path(segments);
+      }
+      cache1.set(str, path);
+    }
+
+    return path;
   }
 
-  public concat(path: Path): Path {
-    const segments = this.segments.concat(path.segments);
-    const wildcard = this.wildcard | (path.wildcard << this.segments.length);
-    const alias = this.alias | (path.alias << this.segments.length);
-    return new Path(segments, wildcard, alias);
+  public concat(path2: Path): Path {
+    if (!path2._string) return this;
+    else if (!this._string) return path2;
+
+    const str = `${this._string}.${path2._string}`;
+
+    let path = cache1.get(str);
+    if (!path) {
+      path = cache2.get(str);
+      if (!path) {
+        const segments = this.segments.concat(path2.segments);
+        Object.freeze(segments);
+        path = new Path(segments);
+      }
+      cache1.set(str, path);
+    }
+
+    return path;
   }
 
   public stripAlias(): Path {
     if (!this.alias) return this;
     const segments = this.segments.map(s => (Array.isArray(s) ? "*" : s));
-    return new Path(segments, this.wildcard | this.alias, 0);
+    const str = segments.join(".");
+
+    let path = cache1.get(str);
+    if (!path) {
+      path = cache2.get(str);
+      if (!path) {
+        Object.freeze(segments);
+        path = new Path(segments);
+      }
+      cache1.set(str, path);
+    }
+
+    return path;
   }
 }
 
diff --git a/test/path-set.ts b/test/path-set.ts
new file mode 100644
index 0000000..a48b4f9
--- /dev/null
+++ b/test/path-set.ts
@@ -0,0 +1,68 @@
+import ava from "ava";
+import Path from "../lib/common/path";
+import PathSet from "../lib/common/path-set";
+
+ava("depth", t => {
+  const pathSet = new PathSet();
+  t.is(pathSet.depth, 0);
+  pathSet.add(Path.parse(""));
+  t.is(pathSet.depth, 1);
+  pathSet.add(Path.parse("a"));
+  t.is(pathSet.depth, 2);
+});
+
+ava("add", t => {
+  const pathSet = new PathSet();
+  pathSet.add(Path.parse("a"));
+  pathSet.add(Path.parse("a"));
+  t.is(pathSet.find(Path.parse("a"), true, true, 99).length, 1);
+});
+
+ava("get", t => {
+  const pathSet = new PathSet();
+  pathSet.add(Path.parse("a.*"));
+  pathSet.add(Path.parse("a.a"));
+  pathSet.add(Path.parse("*.*"));
+
+  t.is(pathSet.get(Path.parse("a.*")).toString(), "a.*");
+  t.is(pathSet.get(Path.parse("*.a")), null);
+});
+
+ava("find", t => {
+  const pathSet = new PathSet();
+  pathSet.add(Path.parse("a"));
+  pathSet.add(Path.parse("a.*"));
+  pathSet.add(Path.parse("a.a"));
+  pathSet.add(Path.parse("*.a"));
+  pathSet.add(Path.parse("*.*"));
+
+  t.deepEqual(
+    pathSet.find(Path.parse(""), true, true, 1).map(p => p.toString()),
+    ["a"]
+  );
+
+  t.deepEqual(
+    pathSet.find(Path.parse(""), false, false, 2).map(p => p.toString()),
+    ["a", "a.*", "a.a", "*.a", "*.*"]
+  );
+
+  t.deepEqual(
+    pathSet.find(Path.parse("a.*"), false, false).map(p => p.toString()),
+    ["a.*"]
+  );
+
+  t.deepEqual(
+    pathSet.find(Path.parse("a.*"), false, true).map(p => p.toString()),
+    ["a.*", "a.a"]
+  );
+
+  t.deepEqual(
+    pathSet.find(Path.parse("a.*"), true, false).map(p => p.toString()),
+    ["a.*", "*.*"]
+  );
+
+  t.deepEqual(
+    pathSet.find(Path.parse("a.*"), true, true).map(p => p.toString()),
+    ["a.*", "a.a", "*.a", "*.*"]
+  );
+});