Merge pull request #657 from evoskuil/master

Add store prune method.

Author: evoskuil

include/bitcoin/database/error.hpp

@@ -91,6 +91,7 @@ enum error_t : uint8_t
     /// tables
     create_table,
     close_table,
+    prune_table,
     backup_table,
     restore_table,
     verify_table,

include/bitcoin/database/impl/store.ipp

@@ -19,6 +19,7 @@
 #ifndef LIBBITCOIN_DATABASE_STORE_IPP
 #define LIBBITCOIN_DATABASE_STORE_IPP
 
+#include <chrono>
 #include <unordered_map>
 #include <bitcoin/system.hpp>
 #include <bitcoin/database/boost.hpp>
@@ -49,6 +50,7 @@ const std::unordered_map<event_t, std::string> CLASS::events
 
     { event_t::wait_lock, "wait_lock" },
     { event_t::flush_body, "flush_body" },
+    { event_t::prune_table, "prune_table" },
     { event_t::backup_table, "backup_table" },
     { event_t::copy_header, "copy_header" },
     { event_t::archive_snapshot, "archive_snapshot" },
@@ -416,6 +418,61 @@ code CLASS::open(const event_handler& handler) NOEXCEPT
     return ec;
 }
 
+TEMPLATE
+code CLASS::prune(const event_handler& handler) NOEXCEPT
+{
+    while (!transactor_mutex_.try_lock_for(std::chrono::seconds(1)))
+    {
+        handler(event_t::wait_lock, table_t::store);
+    }
+
+    code ec{ error::success };
+    const auto prune = [&handler](code& ec, auto& storage, table_t table) NOEXCEPT
+    {
+        if (!ec)
+        {
+            handler(event_t::prune_table, table);
+            if (!storage.reset())
+                ec = error::prune_table;
+        }
+    };
+
+    const auto unload = [&handler](code& ec, auto& storage, table_t table) NOEXCEPT
+    {
+        if (!ec)
+        {
+            handler(event_t::unload_file, table);
+            ec = storage.unload();
+        }
+    };
+
+    const auto load = [&handler](code& ec, auto& storage, table_t table) NOEXCEPT
+    {
+        if (!ec)
+        {
+            handler(event_t::load_file, table);
+            ec = storage.load();
+        }
+    };
+
+    // Prevouts resettable if all candidates confirmed (fork is candidate top).
+    const query<CLASS> query_{ *this };
+    if (query_.get_fork() == query_.get_top_candidate())
+    {
+        // zeroize table head, set body logical size to zero.
+        prune(ec, prevout, table_t::prevout_table);
+
+        // unmap body, setting mapped size to logical size (zero).
+        unload(ec, prevout_body_, table_t::prevout_body);
+
+        // map body, making table usable again.
+        load(ec, prevout_body_, table_t::prevout_body);
+    }
+
+    transactor_mutex_.unlock();
+    return ec;
+}
+
 TEMPLATE
 code CLASS::snapshot(const event_handler& handler) NOEXCEPT
 {

include/bitcoin/database/primitives/arraymap.hpp

@@ -76,7 +76,7 @@ class arraymap
     /// Capacity of body in bytes.
     size_t capacity() const NOEXCEPT;
 
-    /// Increase count as neccesary to specified.
+    /// Increase count as necessary to specified.
     bool expand(const Link& count) NOEXCEPT;
 
     /// Errors.

include/bitcoin/database/primitives/hashmap.hpp

@@ -79,7 +79,7 @@ class hashmap
     /// Capacity of body in bytes.
     size_t capacity() const NOEXCEPT;
 
-    /// Increase count as neccesary to specified.
+    /// Increase count as necessary to specified.
     bool expand(const Link& count) NOEXCEPT;
 
     /// Diagnostic counters.

include/bitcoin/database/primitives/nomap.hpp

@@ -71,7 +71,7 @@ class nomap
     /// Reduce count as specified.
     bool truncate(const Link& count) NOEXCEPT;
 
-    /// Increase count as neccesary to specified.
+    /// Increase count as necessary to specified.
     bool expand(const Link& count) NOEXCEPT;
 
     /// Errors.

include/bitcoin/database/store.hpp

@@ -63,6 +63,9 @@ class store
     /// Open and load the set of tables, set locks.
     code open(const event_handler& handler) NOEXCEPT;
 
+    /// Prune prunable tables (from loaded, leaves loaded).
+    code prune(const event_handler& handler) NOEXCEPT;
+
     /// Snapshot the set of tables (from loaded, leaves loaded).
     code snapshot(const event_handler& handler) NOEXCEPT;
 

include/bitcoin/database/tables/event.hpp

@@ -36,6 +36,7 @@ enum class event_t
 
     wait_lock,
     flush_body,
+    prune_table,
     backup_table,
     copy_header,
     archive_snapshot,

src/error.cpp

@@ -83,6 +83,7 @@ DEFINE_ERROR_T_MESSAGE_MAP(error)
     // tables
     { create_table, "failed to create table" },
     { close_table, "failed to close table" },
+    { prune_table, "failed to prune table" },
     { backup_table, "failed to backup table" },
     { restore_table, "failed to restore table" },
     { verify_table, "failed to verify table" },

test/error.cpp

@@ -329,6 +329,15 @@ BOOST_AUTO_TEST_CASE(error_t__code__close_table__true_exected_message)
     BOOST_REQUIRE_EQUAL(ec.message(), "failed to close table");
 }
 
+BOOST_AUTO_TEST_CASE(error_t__code__prune_table__true_exected_message)
+{
+    constexpr auto value = error::prune_table;
+    const auto ec = code(value);
+    BOOST_REQUIRE(ec);
+    BOOST_REQUIRE(ec == value);
+    BOOST_REQUIRE_EQUAL(ec.message(), "failed to prune table");
+}
+
 BOOST_AUTO_TEST_CASE(error_t__code__backup_table__true_exected_message)
 {
     constexpr auto value = error::backup_table;

test/query/archive_read.cpp

@@ -40,8 +40,7 @@ struct query_archive_read_setup_fixture
 
 BOOST_FIXTURE_TEST_SUITE(query_archive_read_tests, query_archive_read_setup_fixture)
 
-const auto events_handler = [](auto, auto) {};
-
+////const auto events_handler = [](auto, auto) {};
 
 BOOST_AUTO_TEST_CASE(query_archive_read_test)
 {