Fix restore under table regress, re-optimize posix heads.

builds/gnu/Makefile.am

@@ -109,6 +109,7 @@ include_bitcoin_database_impl_primitives_HEADERS = \
     ${srcdir}/../../include/bitcoin/database/impl/primitives/hashhead.ipp \
     ${srcdir}/../../include/bitcoin/database/impl/primitives/hashmap.ipp \
     ${srcdir}/../../include/bitcoin/database/impl/primitives/hashmaps.ipp \
+    ${srcdir}/../../include/bitcoin/database/impl/primitives/headmap.ipp \
     ${srcdir}/../../include/bitcoin/database/impl/primitives/iterator.ipp \
     ${srcdir}/../../include/bitcoin/database/impl/primitives/keys.ipp \
     ${srcdir}/../../include/bitcoin/database/impl/primitives/linkage.ipp \
@@ -249,6 +250,7 @@ include_bitcoin_database_primitives_HEADERS = \
     ${srcdir}/../../include/bitcoin/database/primitives/hashhead.hpp \
     ${srcdir}/../../include/bitcoin/database/primitives/hashmap.hpp \
     ${srcdir}/../../include/bitcoin/database/primitives/hashmaps.hpp \
+    ${srcdir}/../../include/bitcoin/database/primitives/headmap.hpp \
     ${srcdir}/../../include/bitcoin/database/primitives/iterator.hpp \
     ${srcdir}/../../include/bitcoin/database/primitives/keys.hpp \
     ${srcdir}/../../include/bitcoin/database/primitives/linkage.hpp \
@@ -371,6 +373,7 @@ test_libbitcoin_database_test_SOURCES = \
     ${srcdir}/../../test/primitives/hashhead.cpp \
     ${srcdir}/../../test/primitives/hashmap.cpp \
     ${srcdir}/../../test/primitives/hashmaps.cpp \
+    ${srcdir}/../../test/primitives/headmap.cpp \
     ${srcdir}/../../test/primitives/iterator.cpp \
     ${srcdir}/../../test/primitives/keys.cpp \
     ${srcdir}/../../test/primitives/linkage.cpp \

builds/msvc/vs2022/libbitcoin-database-test/libbitcoin-database-test.vcxproj

@@ -139,6 +139,7 @@
     <ClCompile Include="..\..\..\..\test\primitives\hashhead.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\hashmap.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\hashmaps.cpp" />
+    <ClCompile Include="..\..\..\..\test\primitives\headmap.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\iterator.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\keys.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\linkage.cpp" />

builds/msvc/vs2022/libbitcoin-database-test/libbitcoin-database-test.vcxproj.filters

@@ -117,6 +117,9 @@
     <ClCompile Include="..\..\..\..\test\primitives\hashmaps.cpp">
       <Filter>src\primitives</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\..\..\test\primitives\headmap.cpp">
+      <Filter>src\primitives</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\..\..\test\primitives\iterator.cpp">
       <Filter>src\primitives</Filter>
     </ClCompile>

builds/msvc/vs2022/libbitcoin-database/libbitcoin-database.vcxproj

@@ -171,6 +171,7 @@
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\hashhead.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\hashmap.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\hashmaps.hpp" />
+    <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\headmap.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\iterator.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\keys.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\linkage.hpp" />
@@ -236,6 +237,7 @@
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\hashhead.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\hashmap.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\hashmaps.ipp" />
+    <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\headmap.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\iterator.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\keys.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\linkage.ipp" />

builds/msvc/vs2022/libbitcoin-database/libbitcoin-database.vcxproj.filters

@@ -230,6 +230,9 @@
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\hashmaps.hpp">
       <Filter>include\bitcoin\database\primitives</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\headmap.hpp">
+      <Filter>include\bitcoin\database\primitives</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\iterator.hpp">
       <Filter>include\bitcoin\database\primitives</Filter>
     </ClInclude>
@@ -421,6 +424,9 @@
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\hashmaps.ipp">
       <Filter>include\bitcoin\database\impl\primitives</Filter>
     </None>
+    <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\headmap.ipp">
+      <Filter>include\bitcoin\database\impl\primitives</Filter>
+    </None>
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\iterator.ipp">
       <Filter>include\bitcoin\database\impl\primitives</Filter>
     </None>

builds/msvc/vs2026/libbitcoin-database-test/libbitcoin-database-test.vcxproj

@@ -139,6 +139,7 @@
     <ClCompile Include="..\..\..\..\test\primitives\hashhead.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\hashmap.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\hashmaps.cpp" />
+    <ClCompile Include="..\..\..\..\test\primitives\headmap.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\iterator.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\keys.cpp" />
     <ClCompile Include="..\..\..\..\test\primitives\linkage.cpp" />

builds/msvc/vs2026/libbitcoin-database-test/libbitcoin-database-test.vcxproj.filters

@@ -117,6 +117,9 @@
     <ClCompile Include="..\..\..\..\test\primitives\hashmaps.cpp">
       <Filter>src\primitives</Filter>
     </ClCompile>
+    <ClCompile Include="..\..\..\..\test\primitives\headmap.cpp">
+      <Filter>src\primitives</Filter>
+    </ClCompile>
     <ClCompile Include="..\..\..\..\test\primitives\iterator.cpp">
       <Filter>src\primitives</Filter>
     </ClCompile>

builds/msvc/vs2026/libbitcoin-database/libbitcoin-database.vcxproj

@@ -171,6 +171,7 @@
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\hashhead.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\hashmap.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\hashmaps.hpp" />
+    <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\headmap.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\iterator.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\keys.hpp" />
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\linkage.hpp" />
@@ -236,6 +237,7 @@
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\hashhead.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\hashmap.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\hashmaps.ipp" />
+    <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\headmap.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\iterator.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\keys.ipp" />
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\linkage.ipp" />

builds/msvc/vs2026/libbitcoin-database/libbitcoin-database.vcxproj.filters

@@ -230,6 +230,9 @@
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\hashmaps.hpp">
       <Filter>include\bitcoin\database\primitives</Filter>
     </ClInclude>
+    <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\headmap.hpp">
+      <Filter>include\bitcoin\database\primitives</Filter>
+    </ClInclude>
     <ClInclude Include="..\..\..\..\include\bitcoin\database\primitives\iterator.hpp">
       <Filter>include\bitcoin\database\primitives</Filter>
     </ClInclude>
@@ -421,6 +424,9 @@
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\hashmaps.ipp">
       <Filter>include\bitcoin\database\impl\primitives</Filter>
     </None>
+    <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\headmap.ipp">
+      <Filter>include\bitcoin\database\impl\primitives</Filter>
+    </None>
     <None Include="..\..\..\..\include\bitcoin\database\impl\primitives\iterator.ipp">
       <Filter>include\bitcoin\database\impl\primitives</Filter>
     </None>

include/bitcoin/database.hpp

@@ -48,6 +48,7 @@
 #include <bitcoin/database/primitives/hashhead.hpp>
 #include <bitcoin/database/primitives/hashmap.hpp>
 #include <bitcoin/database/primitives/hashmaps.hpp>
+#include <bitcoin/database/primitives/headmap.hpp>
 #include <bitcoin/database/primitives/iterator.hpp>
 #include <bitcoin/database/primitives/keys.hpp>
 #include <bitcoin/database/primitives/linkage.hpp>

include/bitcoin/database/impl/memory/mmap_staging.ipp

@@ -514,7 +514,7 @@ bool CLASS::lazy_install_() NOEXCEPT
 
     // Commit the remainder to the commitment target and populate the tail.
     const auto target = std::max(page_ceiling(to_width<zero>(
-        capacity_.load())), page_ceiling(logical));
+        to_commitment())), page_ceiling(logical));
     if ((target > floor) && (mmap_commit(std::next(memory_map_[zero], floor),
         target - floor, headroom_) == fail))
     {
@@ -538,7 +538,7 @@ bool CLASS::lazy_install_() NOEXCEPT
             bit_all<uint64_t> : unmask_right<uint64_t>(flags - first));
     }
 
-    engaged_.store(true);
+    lazy_.store(true);
 
     // Attribute the anonymous span for diagnostics (smaps decomposition).
     mmap_name(std::next(memory_map_[zero], floor), reserved - floor,

include/bitcoin/database/impl/memory/mmap_storage.ipp

@@ -205,7 +205,7 @@ void CLASS::prepare(size_t STAGING_ONLY(offset),
     // in flight across passes; the count persists until mark.
     writers_.fetch_add(one);
 
-    if (!engaged_.load(relaxed))
+    if (!engaged_.load(relaxed) && !lazy_.load(relaxed))
         return;
 
     // Declare intent before the write (sequentially consistent, pairing with

include/bitcoin/database/impl/primitives/headmap.ipp

@@ -0,0 +1,213 @@
+/**
+ * Copyright (c) 2011-2026 libbitcoin developers
+ *
+ * This file is part of libbitcoin.
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU Affero General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU Affero General Public License for more details.
+ *
+ * You should have received a copy of the GNU Affero General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+#ifndef LIBBITCOIN_DATABASE_PRIMITIVES_HEADMAP_IPP
+#define LIBBITCOIN_DATABASE_PRIMITIVES_HEADMAP_IPP
+
+#include <bitcoin/database/define.hpp>
+
+namespace libbitcoin {
+namespace database {
+
+TEMPLATE
+CLASS::headmap(storage& head) NOEXCEPT
+  : file_(head)
+{
+}
+
+// not thread safe
+// ----------------------------------------------------------------------------
+
+TEMPLATE
+bool CLASS::create() NOEXCEPT
+{
+    // An empty head is a zero count.
+    return is_zero(head_size());
+}
+
+TEMPLATE
+bool CLASS::close() NOEXCEPT
+{
+    // Count is the head logical size.
+    return true;
+}
+
+TEMPLATE
+bool CLASS::backup(bool) NOEXCEPT
+{
+    // Count is the head logical size.
+    return true;
+}
+
+TEMPLATE
+bool CLASS::restore() NOEXCEPT
+{
+    // Content is fully restored with the head, so there is nothing to prune.
+    return verify();
+}
+
+TEMPLATE
+bool CLASS::verify() const NOEXCEPT
+{
+    return is_zero(head_size() % bucket_size);
+}
+
+// sizing
+// ----------------------------------------------------------------------------
+
+TEMPLATE
+size_t CLASS::head_size() const NOEXCEPT
+{
+    return file_.size();
+}
+
+TEMPLATE
+size_t CLASS::body_size() const NOEXCEPT
+{
+    // There is no body (all content is in the head).
+    return zero;
+}
+
+TEMPLATE
+Link CLASS::count() const NOEXCEPT
+{
+    return position_to_link(head_size());
+}
+
+TEMPLATE
+bool CLASS::truncate(const Link& count) NOEXCEPT
+{
+    if (count.is_terminal())
+        return false;
+
+    return file_.truncate(link_to_position(count));
+}
+
+TEMPLATE
+bool CLASS::reserve(const Link& count) NOEXCEPT
+{
+    if (count.is_terminal())
+        return false;
+
+    return file_.reserve(link_to_position(count));
+}
+
+// error condition
+// ----------------------------------------------------------------------------
+
+TEMPLATE
+code CLASS::get_fault() const NOEXCEPT
+{
+    return file_.get_fault();
+}
+
+TEMPLATE
+size_t CLASS::get_space() const NOEXCEPT
+{
+    return file_.get_space();
+}
+
+TEMPLATE
+code CLASS::reload() NOEXCEPT
+{
+    return error::success;
+}
+
+// query interface
+// ----------------------------------------------------------------------------
+
+TEMPLATE
+Link CLASS::at(size_t index) const NOEXCEPT
+{
+    using namespace system;
+
+    // Buckets at or above the logical size are unallocated (count publishes).
+    if (index >= count())
+        return {};
+
+    const auto ptr = file_.get(link_to_position(index));
+    if (!ptr)
+        return {};
+
+    const auto raw = ptr.data();
+    if constexpr (aligned)
+    {
+        // Reads full padded word (masked by to_link).
+        const auto& head = *pointer_cast<std::atomic<cell>>(raw);
+        return to_link(head.load(std::memory_order_relaxed));
+    }
+    else
+    {
+        const auto& head = cell_array(raw);
+        cell value{};
+
+        mutex_.lock_shared();
+        cell_array(value) = head;
+        mutex_.unlock_shared();
+
+        return to_link(value);
+    }
+}
+
+// NOT WRITER-WRITER THREAD SAFE (the logical top is read-write).
+TEMPLATE
+bool CLASS::push(const Link& link) NOEXCEPT
+{
+    using namespace system;
+    if (link.is_terminal())
+        return false;
+
+    const auto position = head_size();
+
+    // Dispose accessor (lock) before allocate.
+    {
+        const auto ptr = file_.get_capacity(position);
+        if (!ptr || (ptr.size() < possible_narrow_sign_cast<ptrdiff_t>(
+            bucket_size)))
+            return false;
+
+        // Writes into unpublished capacity.
+        file_.prepare(position, bucket_size);
+        const auto raw = ptr.data();
+        cell value = link.value;
+        if constexpr (aligned)
+        {
+            // Writes full padded word.
+            auto& head = *pointer_cast<std::atomic<cell>>(raw);
+            head.store(value, std::memory_order_relaxed);
+        }
+        else
+        {
+            auto& head = cell_array(raw);
+
+            mutex_.lock();
+            head = cell_array(value);
+            mutex_.unlock();
+        }
+
+        file_.mark(position, bucket_size);
+    }
+
+    // Publication of the pre-written bucket is its allocation.
+    return file_.allocate(bucket_size) != storage::eof;
+}
+
+} // namespace database
+} // namespace libbitcoin
+
+#endif