From 87b3b84471c7041c29474840616cd3f15705eabe Mon Sep 17 00:00:00 2001
From: Chris Lu <chris.lu@gmail.com>
Date: Sat, 26 May 2018 21:24:03 -0700
Subject: [PATCH] simplifying dirhash to 64bit integer

---
 .../filer2/abstract_sql/abstract_sql_store.go | 10 ++++----
 weed/filer2/abstract_sql/hashing.go           | 25 ++++++++++++++++---
 weed/filer2/configuration.go                  | 19 +++++++++-----
 3 files changed, 40 insertions(+), 14 deletions(-)

diff --git a/weed/filer2/abstract_sql/abstract_sql_store.go b/weed/filer2/abstract_sql/abstract_sql_store.go
index 3d15c632d..900056dae 100644
--- a/weed/filer2/abstract_sql/abstract_sql_store.go
+++ b/weed/filer2/abstract_sql/abstract_sql_store.go
@@ -21,7 +21,7 @@ func (store *AbstractSqlStore) InsertEntry(entry *filer2.Entry) (err error) {
 	}
 
 	res, err := store.DB.Exec("INSERT INTO filemeta (dirhash,name,directory,meta) VALUES(?,?,?,?)",
-		md5hash(dir), name, dir, meta)
+		hashToLong(dir), name, dir, meta)
 	if err != nil {
 		return fmt.Errorf("mysql insert %s: %s", entry.FullPath, err)
 	}
@@ -42,7 +42,7 @@ func (store *AbstractSqlStore) UpdateEntry(entry *filer2.Entry) (err error) {
 	}
 
 	res, err := store.DB.Exec("UPDATE filemeta SET meta=? WHERE dirhash=? AND name=? AND directory=?",
-		meta, md5hash(dir), name, dir)
+		meta, hashToLong(dir), name, dir)
 	if err != nil {
 		return fmt.Errorf("mysql update %s: %s", entry.FullPath, err)
 	}
@@ -58,7 +58,7 @@ func (store *AbstractSqlStore) FindEntry(fullpath filer2.FullPath) (*filer2.Entr
 
 	dir, name := fullpath.DirAndName()
 	row := store.DB.QueryRow("SELECT meta FROM filemeta WHERE dirhash=? AND name=? AND directory=?",
-		md5hash(dir), name, dir)
+		hashToLong(dir), name, dir)
 	var data []byte
 	if err := row.Scan(&data); err != nil {
 		return nil, fmt.Errorf("mysql read entry %s: %v", fullpath, err)
@@ -81,7 +81,7 @@ func (store *AbstractSqlStore) DeleteEntry(fullpath filer2.FullPath) (*filer2.En
 	dir, name := fullpath.DirAndName()
 
 	res, err := store.DB.Exec("DELETE FROM filemeta WHERE dirhash=? AND name=? AND directory=?",
-		md5hash(dir), name, dir)
+		hashToLong(dir), name, dir)
 	if err != nil {
 		return nil, fmt.Errorf("mysql delete %s: %s", fullpath, err)
 	}
@@ -101,7 +101,7 @@ func (store *AbstractSqlStore) ListDirectoryEntries(fullpath filer2.FullPath, st
 		sqlText = "SELECT NAME, meta FROM filemeta WHERE dirhash=? AND name>=? AND directory=? LIMIT ?"
 	}
 
-	rows, err := store.DB.Query(sqlText, md5hash(string(fullpath)), startFileName, string(fullpath), limit)
+	rows, err := store.DB.Query(sqlText, hashToLong(string(fullpath)), startFileName, string(fullpath), limit)
 	if err != nil {
 		return nil, fmt.Errorf("mysql list %s : %v", fullpath, err)
 	}
diff --git a/weed/filer2/abstract_sql/hashing.go b/weed/filer2/abstract_sql/hashing.go
index 5e1390233..5c982c537 100644
--- a/weed/filer2/abstract_sql/hashing.go
+++ b/weed/filer2/abstract_sql/hashing.go
@@ -5,9 +5,28 @@ import (
 	"io"
 )
 
-// returns a 128 bit hash
-func md5hash(dir string) []byte {
+// returns a 64 bit big int
+func hashToLong(dir string) (v int64) {
 	h := md5.New()
 	io.WriteString(h, dir)
-	return h.Sum(nil)
+
+	b := h.Sum(nil)
+
+	v += int64(b[0])
+	v <<= 8
+	v += int64(b[1])
+	v <<= 8
+	v += int64(b[2])
+	v <<= 8
+	v += int64(b[3])
+	v <<= 8
+	v += int64(b[4])
+	v <<= 8
+	v += int64(b[5])
+	v <<= 8
+	v += int64(b[6])
+	v <<= 8
+	v += int64(b[7])
+
+	return
 }
diff --git a/weed/filer2/configuration.go b/weed/filer2/configuration.go
index 910ddcbbc..14ca61745 100644
--- a/weed/filer2/configuration.go
+++ b/weed/filer2/configuration.go
@@ -27,9 +27,9 @@ dir = "."					# directory to store level db files
 # need to manually create a table "filemeta".
 #
 # CREATE TABLE IF NOT EXISTS filemeta (
-#   dirhash     BINARY(16)   COMMENT 'MD5 hash value of directory field',
-#   name        VARCHAR(1000) NOT NULL DEFAULT "" COMMENT 'directory or file name',
-#   directory   VARCHAR(4096) NOT NULL DEFAULT "" COMMENT 'full path to parent directory',
+#   dirhash     BIGINT        COMMENT 'first 64 bits of MD5 hash value of directory field',
+#   name        VARCHAR(1000) COMMENT 'directory or file name',
+#   directory   VARCHAR(4096) COMMENT 'full path to parent directory',
 #   meta        BLOB,
 #   PRIMARY KEY (dirhash, name)
 # ) DEFAULT CHARSET=utf8;
@@ -44,10 +44,17 @@ connection_max_idle = 2
 connection_max_open = 100
 
 [postgres]
+# CREATE TABLE IF NOT EXISTS filemeta (
+#   dirhash     BIGINT,
+#   name        VARCHAR(1000),
+#   directory   VARCHAR(4096),
+#   meta        bytea,
+#   PRIMARY KEY (dirhash, name)
+# );
 enabled = false
-server = "192.168.1.1"
-port = 8080
-username = ""
+server = "localhost"
+port = 5432
+username = "postgres"
 password = ""
 database = ""
 connection_max_idle = 100