Revert support for deterministic shards:

Commit 4dc08f8 introduced support for
deterministic shards, which makes the sharding functionality provided
by rippled more useful.

After merging, several opportunities for further improvements to the
deterministic sharding implementation were identified and a significant
increase int memory usage during shard finalization was detected.

Because of these issues, the commit is being reverted and the feature is
being rolled back. It will be reintroduced in a future release.

Builds/CMake/RippledCore.cmake

@@ -515,7 +515,6 @@ target_sources (rippled PRIVATE
   src/ripple/nodestore/impl/DatabaseNodeImp.cpp
   src/ripple/nodestore/impl/DatabaseRotatingImp.cpp
   src/ripple/nodestore/impl/DatabaseShardImp.cpp
-  src/ripple/nodestore/impl/DeterministicShard.cpp
   src/ripple/nodestore/impl/DecodedBlob.cpp
   src/ripple/nodestore/impl/DummyScheduler.cpp
   src/ripple/nodestore/impl/EncodedBlob.cpp

src/ripple/nodestore/Backend.h

@@ -58,25 +58,6 @@ class Backend
     virtual void
     open(bool createIfMissing = true) = 0;
 
-    /** Open the backend.
-        @param createIfMissing Create the database files if necessary.
-        @param appType Deterministic appType used to create a backend.
-        @param uid Deterministic uid used to create a backend.
-        @param salt Deterministic salt used to create a backend.
-        This allows the caller to catch exceptions.
-    */
-    virtual void
-    open(
-        bool createIfMissing,
-        boost::optional<uint64_t> appType,
-        boost::optional<uint64_t> uid,
-        boost::optional<uint64_t> salt)
-    {
-        Throw<std::runtime_error>(std::string(
-            "Deterministic appType/uid/salt not supported by backend " +
-            getName()));
-    }
-
     /** Close the backend.
         This allows the caller to catch exceptions.
     */

src/ripple/nodestore/backend/NuDBFactory.cpp

@@ -38,10 +38,7 @@ namespace NodeStore {
 class NuDBBackend : public Backend
 {
 public:
-    static constexpr std::uint64_t currentType = 1;
-    static constexpr std::uint64_t deterministicType = 0x5348524400000000ull;
-    /* "SHRD" in ASCII */
-    static constexpr std::uint64_t deterministicMask = 0xFFFFFFFF00000000ull;
+    static constexpr std::size_t currentType = 1;
 
     beast::Journal const j_;
     size_t const keyBytes_;
@@ -96,11 +93,7 @@ class NuDBBackend : public Backend
     }
 
     void
-    open(
-        bool createIfMissing,
-        boost::optional<uint64_t> appType,
-        boost::optional<uint64_t> uid,
-        boost::optional<uint64_t> salt) override
+    open(bool createIfMissing) override
     {
         using namespace boost::filesystem;
         if (db_.is_open())
@@ -121,9 +114,8 @@ class NuDBBackend : public Backend
                 dp,
                 kp,
                 lp,
-                appType.value_or(currentType),
-                uid.value_or(nudb::make_uid()),
-                salt.value_or(nudb::make_salt()),
+                currentType,
+                nudb::make_salt(),
                 keyBytes_,
                 nudb::block_size(kp),
                 0.50,
@@ -136,27 +128,10 @@ class NuDBBackend : public Backend
         db_.open(dp, kp, lp, ec);
         if (ec)
             Throw<nudb::system_error>(ec);
-
-        /** Old value currentType is accepted for appnum in traditional
-         *  databases, new value is used for deterministic shard databases.
-         *  New 64-bit value is constructed from fixed and random parts.
-         *  Fixed part is bounded by bitmask deterministicMask,
-         *  and the value of fixed part is deterministicType.
-         *  Random part depends on the contents of the shard and may be any.
-         *  The contents of appnum field should match either old or new rule.
-         */
-        if (db_.appnum() != appType.value_or(currentType) &&
-            (appType ||
-             (db_.appnum() & deterministicMask) != deterministicType))
+        if (db_.appnum() != currentType)
             Throw<std::runtime_error>("nodestore: unknown appnum");
     }
 
-    void
-    open(bool createIfMissing) override
-    {
-        open(createIfMissing, boost::none, boost::none, boost::none);
-    }
-
     void
     close() override
     {