Revert "Parallelize set_strong in the confirmation path."

include/bitcoin/database/impl/query/archive/chain_writer.ipp

@@ -409,8 +409,7 @@ code CLASS::set_code(const block& block, const header_link& key,
     constexpr auto positive = true;
 
     // Transactor assures cannot be restored without txs, as required to unset.
-    // Sequential write, as archival is already concurrent across blocks.
-    if (strong && !set_strong(key, txs, tx_fks, positive, false))
+    if (strong && !set_strong(key, txs, tx_fks, positive))
         return error::txs_confirm;
 
     // Header link is the key for the txs table.

include/bitcoin/database/impl/query/archive/wire_writer.ipp

@@ -347,8 +347,7 @@ code CLASS::set_code(const block_view& block, const header_link& key,
     constexpr auto positive = true;
 
     // Transactor assures cannot be restored without txs, as required to unset.
-    // Sequential write, as archival is already concurrent across blocks.
-    if (strong && !set_strong(key, txs, tx_fks, positive, false))
+    if (strong && !set_strong(key, txs, tx_fks, positive))
         return error::txs_confirm;
 
     // Header link is the key for the txs table.

include/bitcoin/database/impl/query/consensus/consensus_strong.ipp

@@ -19,7 +19,6 @@
 #ifndef LIBBITCOIN_DATABASE_QUERY_CONSENSUS_STRONG_IPP
 #define LIBBITCOIN_DATABASE_QUERY_CONSENSUS_STRONG_IPP
 
-#include <algorithm>
 #include <bitcoin/database/define.hpp>
 
 namespace libbitcoin {
@@ -108,33 +107,27 @@ header_link CLASS::find_strong(const hash_digest& tx_hash) const NOEXCEPT
 // protected
 TEMPLATE
 bool CLASS::set_strong(const header_link& link, size_t count,
-    const tx_link& first_fk, bool positive, bool parallel) NOEXCEPT
+    const tx_link& first_fk, bool positive) NOEXCEPT
 {
     using namespace system;
     using link_t = table::strong_tx::link;
     using element_t = table::strong_tx::record;
-    const auto policy = poolstl::execution::par_if(parallel);
 
     // Preallocate all strong_tx records for the block and reuse memory ptr.
-    // Terminal allocation must not be indexed (would wrap to valid records).
     const auto records = possible_narrow_cast<link_t::integer>(count);
-    const auto record = store_.strong_tx.allocate(records);
-    if (record.is_terminal())
-        return false;
-
+    auto record = store_.strong_tx.allocate(records);
     const auto ptr = store_.strong_tx.get_memory();
+    const auto end = first_fk + count;
+
+    // Contiguous tx links.
+    for (auto fk = first_fk; fk < end; ++fk)
+        if (!store_.strong_tx.put(ptr, record++, fk, element_t
+            {
+                {},
+                table::strong_tx::merge(positive, link)
+            })) return false;
 
-    // All records of the block share one element value.
-    const element_t element{ {}, table::strong_tx::merge(positive, link) };
-
-    // Contiguous tx links to contiguous records.
-    return std::all_of(policy, poolstl::iota_iter<size_t>(zero),
-        poolstl::iota_iter<size_t>(count),
-        [&](size_t index) NOEXCEPT
-        {
-            return store_.strong_tx.put(ptr, record + index, first_fk + index,
-                element);
-        });
+    return true;
 }
 
 TEMPLATE
@@ -151,7 +144,7 @@ bool CLASS::set_strong(const header_link& link) NOEXCEPT
     const auto scope = get_transactor();
 
     // Clean allocation failure (e.g. disk full).
-    return set_strong(link, txs.number, txs.coinbase_fk, true, true);
+    return set_strong(link, txs.number, txs.coinbase_fk , true);
     // ========================================================================
 }
 
@@ -169,7 +162,7 @@ bool CLASS::set_unstrong(const header_link& link) NOEXCEPT
     const auto scope = get_transactor();
 
     // Clean allocation failure (e.g. disk full).
-    return set_strong(link, txs.number, txs.coinbase_fk, false, true);
+    return set_strong(link, txs.number, txs.coinbase_fk, false);
     // ========================================================================
 }
 

include/bitcoin/database/impl/query/height.ipp

@@ -85,7 +85,7 @@ bool CLASS::push_confirmed(const header_link& link, bool strong) NOEXCEPT
     const auto scope = get_transactor();
 
     // This reservation guard assumes no concurrent writes to the table.
-    if (strong && !set_strong(link, txs.number, txs.coinbase_fk, true, true))
+    if (strong && !set_strong(link, txs.number, txs.coinbase_fk, true))
         return false;
 
     const table::height::record confirmed{ {}, link };
@@ -110,7 +110,7 @@ bool CLASS::pop_confirmed() NOEXCEPT
     const auto scope = get_transactor();
 
     // Clean single allocation failure.
-    if (!set_strong(link, txs.number, txs.coinbase_fk, false, true))
+    if (!set_strong(link, txs.number, txs.coinbase_fk, false))
         return false;
 
     ///////////////////////////////////////////////////////////////////////////

include/bitcoin/database/query.hpp

@@ -837,7 +837,7 @@ class query
 
     /// Support set_strong and set_unstrong writers.
     bool set_strong(const header_link& link, size_t count,
-        const tx_link& first_fk, bool positive, bool parallel) NOEXCEPT;
+        const tx_link& first_fk, bool positive) NOEXCEPT;
 
     /// Get all tx links for any point of block that is also in duplicate table.
     bool get_doubles(tx_links& out, const block& block) const NOEXCEPT;