/*****************************************************************************

Copyright (c) 2020, 2024, Oracle and/or its affiliates.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License, version 2.0, as published by the
Free Software Foundation.

This program is designed to work with certain software (including
but not limited to OpenSSL) that is licensed under separate terms,
as designated in a particular file or component or in included license
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permission to link the program and your derivative works with the
separately licensed software that they have either included with
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ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
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for more details.

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this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin St, Fifth Floor, Boston, MA 02110-1301  USA

*****************************************************************************/

/** @file ddl/ddl0builder.cc
 DDL build index implementation.
Created 2020-11-01 by Sunny Bains. */

#include <debug_sync.h>
#include "clone0api.h"
#include "ddl0fts.h"
#include "ddl0impl-builder.h"
#include "ddl0impl-compare.h"
#include "ddl0impl-cursor.h"
#include "ddl0impl-loader.h"
#include "ddl0impl-merge.h"
#include "ddl0impl-rtree.h"
#include "lob0lob.h"
#include "os0thread-create.h"
#include "row0ext.h"
#include "row0vers.h"
#include "ut0stage.h"

namespace ddl {

/** Context for copying cluster index row for the index to being created. */
struct Copy_ctx {
  /** Constructor.
  @param[in] row                Row to copy.
  @param[in,out] my_table       Server table definition.
  @param[in] thread_id          ID of current thread. */
  Copy_ctx(const Row &row, TABLE *my_table, size_t thread_id) noexcept
      : m_row(row), m_my_table(my_table), m_thread_id(thread_id) {}

  /** Row to copy. */
  const Row &m_row;

  /** MySQL table definition. */
  TABLE *m_my_table{};

  /** Number of columns to copy. */
  size_t m_n_fields{};

  /** Number of multivalue rows to add. */
  size_t m_n_mv_rows_to_add{};

  /** For storing multi value data. */
  const multi_value_data *m_mv{};

  /** Number of rows added or UNIV_NO_INDEX_VALUE if this is a multi-value
  index and current row has nothing valid to be indexed. */
  size_t m_n_rows_added{};

  /** Number of bytes copied. */
  size_t m_data_size{};

  /** Number of extra bytes used. */
  size_t m_extra_size{};

  /** Number of rows added during copy. */
  size_t m_n_recs{};

  /** ID of the current thread. */
  size_t m_thread_id{std::numeric_limits<size_t>::max()};
};

/** Generate the next document ID using a monotonic sequence. */
struct Gen_sequence : public ddl::Context::FTS::Sequence {
  /** Constructor.
  @param[in] current            Current (maximum document ID) (> 0). */
  explicit Gen_sequence(doc_id_t current) noexcept {
    ut_a(current > 0);
    m_doc_id = current;
  }

  /** Destructor. */
  ~Gen_sequence() noexcept override {}

  /** Get the next document ID.
  @return the current document ID and advance the sequence. */
  doc_id_t current() noexcept override { return m_doc_id; }

  /** Not supported.
  @param[in] dtuple             Row from which to fetch ID (ignored).
  @return the current document ID. */
  doc_id_t fetch(const dtuple_t *dtuple
                 [[maybe_unused]] = nullptr) noexcept override {
    ut_error;
  }

  /** Advance the document ID. */
  void increment() noexcept override {
    ++m_doc_id;
    ++m_n_generated;
  }

  /** @return the maximum document ID seen so far. */
  [[nodiscard]] doc_id_t max_doc_id() const noexcept override {
    return m_doc_id;
  }

  /** @return true, because we always generate the document ID. */
  [[nodiscard]] bool is_generated() const noexcept override { return true; }

  /** @return the number of document IDs generated. */
  doc_id_t generated_count() const noexcept override { return m_n_generated; }

  /** Number of document IDs generated. */
  doc_id_t m_n_generated{};
};

/** For loading an index from a sorted buffer. */
struct Key_sort_buffer_cursor : public Load_cursor {
  /** Constructor.
  @param[in,out] builder  Index builder.
  @param[in,out] key_buffer     Key buffer to load from. */
  Key_sort_buffer_cursor(Builder *builder, Key_sort_buffer *key_buffer) noexcept
      : Load_cursor(builder, nullptr), m_key_buffer(key_buffer) {}

  /** Open the cursor.
  @return DB_SUCCESS or error code. */
  dberr_t open() noexcept;

  /** Fetch the current row as a tuple. Note: Tuple columns are shallow copies.
  @param[out] dtuple          Row represented as a tuple.
  @return DB_SUCCESS, DB_END_OF_INDEX or error code. */
  [[nodiscard]] dberr_t fetch(dtuple_t *&dtuple) noexcept override;

  /** Move to the next record.
  @return DB_SUCCESS, DB_END_OF_INDEX or error code. */
  [[nodiscard]] dberr_t next() noexcept override;

 private:
  /** Tuple to return. */
  dtuple_t *m_dtuple{};

  /** Number of rows read from the key buffer. */
  size_t m_n_rows{};

  /** Row offsets. */
  ulint *m_offsets{};

  /** Heap for m_offsets and m_buf. */
  Scoped_heap m_heap{};

  /** Current merge row in m_aligned_buffer. */
  const mrec_t *m_mrec{};

  /** Key buffer to read from. */
  Key_sort_buffer *m_key_buffer{};
};

/** For loading a Btree index from a file. */
struct File_cursor : public Load_cursor {
  /** Constructor.
  @param[in] builder            The index build driver.
  @param[in] file               File to read from.
  @param[in] buffer_size        IO buffer size to use for reads.
  @param[in] size               Size of the file in bytes.
  @param[in,out] stage          PFS observability. */
  File_cursor(Builder *builder, const Unique_os_file_descriptor &file,
              size_t buffer_size, os_offset_t size,
              Alter_stage *stage) noexcept;

  /** Destructor. */
  ~File_cursor() override = default;

  /** Open the cursor.
  @return DB_SUCCESS or error code. */
  [[nodiscard]] dberr_t open() noexcept;

  /** Fetch the current row as a tuple. Note: Tuple columns are shallow copies.
  @param[out] dtuple            Row represented as a tuple.
  @return DB_SUCCESS, DB_END_OF_INDEX or error code. */
  [[nodiscard]] dberr_t fetch(dtuple_t *&dtuple) noexcept override;

  /** Fetch the current row.
  @param[out] mrec              Current row.
  @param[out] offsets           Column offsets inside mrec.
  @return DB_SUCCESS, DB_END_OF_INDEX or error code. */
  [[nodiscard]] dberr_t fetch(const mrec_t *&mrec, ulint *&offsets) noexcept;

  /** Move to the next record.
  @return DB_SUCCESS, DB_END_OF_INDEX or error code. */
  [[nodiscard]] dberr_t next() noexcept override;

 private:
  /** Prepare to fetch the current row.
  @return DB_SUCCESS, DB_END_OF_INDEX or error code. */
  [[nodiscard]] dberr_t fetch() noexcept;

 private:
  /** Instance ID. */
  size_t m_id{};

  /** File reader. */
  File_reader m_reader;

  /** Number of rows read the file. */
  uint64_t m_n_rows{};

  /** PFS monitoring. */
  Alter_stage *m_stage{};

  friend struct Merge_cursor;
};

bool Load_cursor::duplicates_detected() const noexcept {
  return m_dup != nullptr && !m_dup->empty();
}

dberr_t File_reader::get_tuple(Builder *builder, mem_heap_t *heap,
                               dtuple_t *&dtuple) noexcept {
  dtuple = row_rec_to_index_entry_low(m_mrec, m_index, &m_offsets[0], heap);
  if (!builder->is_fts_index()) {
    return builder->dtuple_copy_blobs(dtuple, &m_offsets[0], m_mrec, heap);
  } else {
    return DB_SUCCESS;
  }
}

File_cursor::File_cursor(Builder *builder,
                         const Unique_os_file_descriptor &file,
                         size_t buffer_size, os_offset_t size,
                         Alter_stage *stage) noexcept
    : Load_cursor(builder, nullptr),
      m_reader(file, builder->index(), buffer_size, size),
      m_stage(stage) {
  ut_a(m_reader.m_file.is_open());
}

dberr_t File_cursor::open() noexcept {
  m_tuple_heap.create(2048, UT_LOCATION_HERE);

  return m_reader.prepare();
}

dberr_t File_cursor::fetch() noexcept {
  m_tuple_heap.clear();

  if (m_stage != nullptr) {
    m_stage->inc(1);
  }

  return m_builder->get_error();
}

dberr_t File_cursor::fetch(dtuple_t *&dtuple) noexcept {
  m_err = fetch();

  if (unlikely(m_err != DB_SUCCESS)) {
    return m_err;
  }

  m_err = m_reader.get_tuple(m_builder, m_tuple_heap.get(), dtuple);

  ut_a(m_err != DB_END_OF_INDEX);

  return m_err;
}

dberr_t File_cursor::fetch(const mrec_t *&mrec, ulint *&offsets) noexcept {
  m_err = fetch();

  if (unlikely(m_err != DB_SUCCESS)) {
    return m_err;
  }

  mrec = m_reader.m_mrec;
  offsets = &m_reader.m_offsets[0];

  return DB_SUCCESS;
}

dberr_t File_cursor::next() noexcept {
  auto err = m_reader.next();

  if (unlikely(err != DB_END_OF_INDEX)) {
    m_err = err;
  }

  ++m_n_rows;

  return err;
}

Merge_cursor::File_readers Merge_cursor::file_readers() noexcept {
  File_readers file_readers{};

  for (auto file_cursor : m_cursors) {
    file_readers.push_back(&file_cursor->m_reader);
  }

  return file_readers;
}

Merge_cursor::Merge_cursor(Builder *builder, Dup *dup,
                           Alter_stage *stage) noexcept
    : Load_cursor(builder, dup),
      m_pq(Compare(builder->index(), dup)),
      m_stage(stage) {}

Merge_cursor::~Merge_cursor() noexcept {
  for (auto cursor : m_cursors) {
    ut::delete_(cursor);
  }
}

bool Merge_cursor::Compare::operator()(const File_cursor *lhs,
                                       const File_cursor *rhs) const noexcept {
  const auto &l = lhs->m_reader;
  const auto &r = rhs->m_reader;

  ut_a(l.m_index == r.m_index);

  auto cmp = cmp_rec_rec_simple(r.m_mrec, l.m_mrec, &r.m_offsets[0],
                                &l.m_offsets[0], r.m_index,
                                m_dup != nullptr ? m_dup->m_table : nullptr);

  /* Check for duplicates. */
  if (unlikely(cmp == 0 && m_dup != nullptr)) {
    m_dup->report(l.m_mrec, &l.m_offsets[0]);
  }

  return cmp < 0;
}

dberr_t Merge_cursor::add_file(const ddl::file_t &file,
                               size_t buffer_size) noexcept {
  ut_a(file.m_file.is_open());

  auto cursor = ut::new_withkey<File_cursor>(
      ut::make_psi_memory_key(mem_key_ddl), m_builder, file.m_file, buffer_size,
      file.m_size, m_stage);

  if (cursor == nullptr) {
    m_err = DB_OUT_OF_MEMORY;
    return m_err;
  }

  m_cursors.push_back(cursor);

  return DB_SUCCESS;
}

dberr_t Merge_cursor::add_file(const ddl::file_t &file, size_t buffer_size,
                               os_offset_t offset) noexcept {
  auto err = add_file(file, buffer_size);

  if (err != DB_SUCCESS) {
    return err;
  } else {
    m_cursors.back()->m_reader.set_offset(offset);
    return DB_SUCCESS;
  }
}

void Merge_cursor::clear_eof() noexcept {
  ut_a(m_pq.empty());
  ut_a(!m_cursors.empty());
  ut_a(m_err == DB_END_OF_INDEX);

  m_err = DB_SUCCESS;

  for (auto cursor : m_cursors) {
    ut_a(cursor->m_err == DB_END_OF_INDEX);
    if (!cursor->m_reader.eof()) {
      cursor->m_err = DB_SUCCESS;
      m_pq.push(cursor);
    }
  }
}

dberr_t Merge_cursor::open() noexcept {
  ut_a(m_pq.empty());
  ut_a(!m_cursors.empty());

  /* Prime the priority queue and skip empty files. */
  for (auto cursor : m_cursors) {
    ut_a(cursor != nullptr);
    m_err = cursor->open();
    if (m_err == DB_SUCCESS) {
      m_pq.push(cursor);
    } else if (m_err != DB_END_OF_INDEX) {
      return m_err;
    }
  }

  m_err = m_pq.empty() ? DB_END_OF_INDEX : DB_SUCCESS;

  return m_err;
}

File_cursor *Merge_cursor::pop() noexcept {
  ut_a(!m_pq.empty());
  ut_a(m_cursor == nullptr);
  ut_a(m_err == DB_SUCCESS);

  auto cursor = m_pq.top();

  m_pq.pop();

  return cursor;
}

dberr_t Merge_cursor::fetch(dtuple_t *&dtuple) noexcept {
  const auto err = m_builder->check_state_of_online_build_log();

  if (err != DB_SUCCESS) {
    return err;
  } else {
    m_cursor = pop();
    return m_cursor->fetch(dtuple);
  }
}

dberr_t Merge_cursor::fetch(const mrec_t *&rec, ulint *&offsets) noexcept {
  const auto err = m_builder->check_state_of_online_build_log();

  if (err != DB_SUCCESS) {
    return err;
  } else {
    m_cursor = pop();
    return m_cursor->fetch(rec, offsets);
  }
}

dberr_t Merge_cursor::next() noexcept {
  ut_a(m_err == DB_SUCCESS);

  m_err = m_cursor->next();

  if (likely(m_err == DB_SUCCESS)) {
    m_pq.push(m_cursor);
    m_cursor = nullptr;
  } else if (unlikely(m_err == DB_END_OF_INDEX)) {
    m_cursor->m_err = m_err;
    m_cursor = nullptr;
    m_err = m_pq.empty() ? m_err : DB_SUCCESS;
  }

  return m_err;
}

uint64_t Merge_cursor::get_n_rows() const noexcept {
  uint64_t n_rows{};

  for (auto cursor : m_cursors) {
    n_rows += cursor->m_n_rows;
  }

  return n_rows;
}

void Builder::convert(const dict_index_t *clust_index,
                      const dfield_t *row_field, dfield_t *field, ulint len,
                      const page_size_t &page_size,
                      IF_DEBUG(bool is_sdi, ) mem_heap_t *heap) noexcept {
  ut_ad(DATA_MBMAXLEN(field->type.mbminmaxlen) > 1);
  ut_ad(DATA_MBMINLEN(field->type.mbminmaxlen) == 1);

  auto field_len = row_field->len;

  ut_a(field_len <= len);

  const auto buf = reinterpret_cast<byte *>(mem_heap_alloc(heap, len));

  if (row_field->ext) {
    const byte *field_data = static_cast<byte *>(dfield_get_data(row_field));
    ulint ext_len;

    ut_a(field_len >= BTR_EXTERN_FIELD_REF_SIZE);
    ut_ad(memcmp(field_data + field_len - BTR_EXTERN_FIELD_REF_SIZE,
                 field_ref_zero, BTR_EXTERN_FIELD_REF_SIZE));

    const auto data = lob::btr_copy_externally_stored_field_func(
        nullptr, clust_index, &ext_len, nullptr, field_data, page_size,
        field_len, IF_DEBUG(is_sdi, ) heap);

    ut_a(ext_len < len);

    memcpy(buf, data, ext_len);
    field_len = ext_len;
  } else {
    memcpy(buf, row_field->data, field_len);
  }

  memset(buf + field_len, 0x20, len - field_len);

  dfield_set_data(field, buf, len);
}

dberr_t Key_sort_buffer_cursor::open() noexcept {
  auto index = m_builder->index();
  const auto n_fields = dict_index_get_n_fields(index);

  {
    const auto i = 1 + REC_OFFS_HEADER_SIZE + n_fields;

    m_heap.create(1024 + i * sizeof(ulint), UT_LOCATION_HERE);

    const size_t n = i * sizeof(*m_offsets);

    m_offsets = reinterpret_cast<decltype(m_offsets)>(m_heap.alloc(n));

    m_offsets[0] = i;
  }

  m_offsets[1] = n_fields;

  DBUG_EXECUTE_IF("ddl_read_failure", m_err = DB_CORRUPTION; return m_err;);

  m_dtuple = dtuple_create(m_heap.get(), n_fields);

  dtuple_set_n_fields_cmp(m_dtuple, dict_index_get_n_unique_in_tree(index));

  m_tuple_heap.create(2048, UT_LOCATION_HERE);

  return DB_SUCCESS;
}

dberr_t Key_sort_buffer_cursor::fetch(dtuple_t *&dtuple) noexcept {
  m_tuple_heap.clear();

  if (m_n_rows >= m_key_buffer->size()) {
    return DB_END_OF_INDEX;
  }

  const auto fields = m_key_buffer->m_dtuples[m_n_rows];

  memcpy(m_dtuple->fields, fields, m_dtuple->n_fields * sizeof(dfield_t));

  /* "nullptr" - LOB pointers must be copied from the dtuple. */
  m_err = m_builder->dtuple_copy_blobs(m_dtuple, m_offsets, nullptr,
                                       m_tuple_heap.get());

  if (m_err == DB_SUCCESS) {
    dtuple = m_dtuple;
  }

  return m_err;
}

dberr_t Key_sort_buffer_cursor::next() noexcept {
  ++m_n_rows;
  return DB_SUCCESS;
}

Builder::Thread_ctx::Thread_ctx(size_t id, Key_sort_buffer *key_buffer) noexcept
    : m_id(id), m_key_buffer(key_buffer) {}

Builder::Thread_ctx::~Thread_ctx() noexcept {
  if (m_key_buffer != nullptr) {
    ut::delete_(m_key_buffer);
  }

  if (m_rtree_inserter != nullptr) {
    ut::delete_(m_rtree_inserter);
  }
}

Builder::Builder(ddl::Context &ctx, Loader &loader, size_t i) noexcept
    : m_id(i),
      m_ctx(ctx),
      m_loader(loader),
      m_index(ctx.m_indexes[m_id]),
      m_clust_dup({ctx.m_indexes[0], ctx.m_table, ctx.m_col_map, 0}) {
  m_tmpdir = thd_innodb_tmpdir(m_ctx.thd());

  m_sort_index = is_fts_index() ? m_ctx.m_fts.m_ptr->sort_index() : m_index;

  DBUG_EXECUTE_IF("ddl_convert_charset_without_heap_fail", { return; });
  if (!dict_table_is_comp(m_ctx.m_new_table)) {
    /* Converting to redundant format requires heap allocation */
    m_conv_heap.create(sizeof(mrec_buf_t), UT_LOCATION_HERE);
  }
}

Builder::~Builder() noexcept {
  for (auto thread_ctx : m_thread_ctxs) {
    ut::delete_(thread_ctx);
  }

  m_thread_ctxs.clear();

  if (m_local_stage != nullptr) {
    m_local_stage->begin_phase_end();
    ut::delete_(m_local_stage);
  }

  if (m_btr_load != nullptr) {
    ut::delete_(m_btr_load);
    m_btr_load = nullptr;
  }
}

dberr_t Builder::check_state_of_online_build_log() noexcept {
  const auto err = m_ctx.check_state_of_online_build_log();

  if (err != DB_SUCCESS) {
    set_error(err);
  }

  return get_error();
}

dberr_t Builder::init(Cursor &cursor, size_t n_threads) noexcept {
  ut_a(m_thread_ctxs.empty());
  ut_a(get_state() == State::INIT);

  if (m_ctx.m_stage != nullptr) {
    ut_a(m_local_stage == nullptr);
    m_local_stage = ut::new_withkey<Alter_stage>(
        ut::make_psi_memory_key(mem_key_ddl), *m_ctx.m_stage);

    if (m_local_stage == nullptr) {
      return DB_OUT_OF_MEMORY;
    }

    /* Each builder is responsible for building a single index. */
    m_local_stage->begin_phase_read_pk(1);
  }

  auto buffer_size = m_ctx.scan_buffer_size(n_threads);
  auto create_thread_ctx = [&](size_t id, dict_index_t *index) -> dberr_t {
    auto key_buffer = ut::new_withkey<Key_sort_buffer>(
        ut::make_psi_memory_key(mem_key_ddl), index, buffer_size.first);

    if (key_buffer == nullptr) {
      return DB_OUT_OF_MEMORY;
    }

    auto thread_ctx = ut::new_withkey<Thread_ctx>(
        ut::make_psi_memory_key(mem_key_ddl), id, key_buffer);

    if (thread_ctx == nullptr) {
      ut::delete_(key_buffer);
      key_buffer = nullptr;
    }

    m_thread_ctxs.push_back(thread_ctx);

    thread_ctx->m_aligned_buffer =
        ut::make_unique_aligned<byte[]>(ut::make_psi_memory_key(mem_key_ddl),
                                        UNIV_SECTOR_SIZE, buffer_size.second);

    if (!thread_ctx->m_aligned_buffer) {
      return DB_OUT_OF_MEMORY;
    }

    thread_ctx->m_io_buffer = {thread_ctx->m_aligned_buffer.get(),
                               buffer_size.second};

    if (is_spatial_index()) {
      thread_ctx->m_rtree_inserter = ut::new_withkey<RTree_inserter>(
          ut::make_psi_memory_key(mem_key_ddl), m_ctx, index);

      if (thread_ctx->m_rtree_inserter == nullptr ||
          !thread_ctx->m_rtree_inserter->is_initialized()) {
        ut::delete_(key_buffer);
        return DB_OUT_OF_MEMORY;
      }
    }

    return DB_SUCCESS;
  };

  if (is_fts_index()) {
    auto &fts = m_ctx.m_fts;
    auto new_table = m_ctx.m_new_table;

    ut_a(fts.m_doc_id == nullptr);

    if (DICT_TF2_FLAG_IS_SET(new_table, DICT_TF2_FTS_ADD_DOC_ID)) {
      /* Generate the document ID. */
      doc_id_t current{};
      auto table = reinterpret_cast<dict_table_t *>(new_table);

      /* Fetch the FTS Doc ID from the row. */
      fts_get_next_doc_id(table, &current);

      fts.m_doc_id = ut::new_withkey<Gen_sequence>(
          ut::make_psi_memory_key(mem_key_ddl), current);
    } else {
      fts.m_doc_id = ut::new_withkey<Fetch_sequence>(
          ut::make_psi_memory_key(mem_key_ddl), fts.m_ptr->index());
    }

    if (fts.m_doc_id == nullptr) {
      set_error(DB_OUT_OF_MEMORY);
      set_next_state();
      return get_error();
    }

    ut_a(m_sort_index == fts.m_ptr->sort_index());

    fts.m_ptr->start_parse_threads(this);
  } else {
    ut_a(m_sort_index == m_index);
  }

  for (size_t i = 0; i < n_threads; ++i) {
    auto err = create_thread_ctx(i, m_sort_index);

    if (err != DB_SUCCESS) {
      set_error(err);
      set_next_state();
      return get_error();
    }
  }

  if (cursor.m_row_heap.get() == nullptr) {
    cursor.m_row_heap.create(sizeof(mrec_buf_t), UT_LOCATION_HERE);

    if (cursor.m_row_heap.get() == nullptr) {
      set_error(DB_OUT_OF_MEMORY);
      set_next_state();
      return get_error();
    }
  }

  if (is_skip_file_sort()) {
    ut_a(m_btr_load == nullptr);
    const auto trx_id = m_ctx.m_trx->id;
    auto observer = m_ctx.flush_observer();

    m_btr_load = ut::new_withkey<Btree_load>(
        ut::make_psi_memory_key(mem_key_ddl), m_index, trx_id, observer);

    if (m_btr_load == nullptr) {
      set_error(DB_OUT_OF_MEMORY);
      set_next_state();
      return get_error();
    }
  }

  set_next_state();
  ut_a(get_state() != State::INIT);

  return DB_SUCCESS;
}

void Builder::fts_add_doc_id(dfield_t *dst, const dict_field_t *src,
                             doc_id_t &write_doc_id) noexcept {
  auto &fts = m_ctx.m_fts;
  const auto doc_id = fts.m_doc_id->current();

  ut_a(doc_id <= 4294967295u);

  fts_write_doc_id(reinterpret_cast<byte *>(&write_doc_id), doc_id);

  dfield_set_data(dst, &write_doc_id, sizeof(write_doc_id));

  dst->type.len = src->col->len;
  dst->type.mtype = src->col->mtype;
  dst->type.prtype = src->col->prtype;
  dst->type.mbminmaxlen = DATA_MBMINMAXLEN(0, 0);
}

dberr_t Builder::get_virtual_column(Copy_ctx &ctx, const dict_field_t *ifield,
                                    dict_col_t *col, dfield_t *&src_field,
                                    size_t &mv_rows_added) noexcept {
  const auto n_added = mv_rows_added;
  auto v_col = reinterpret_cast<const dict_v_col_t *>(col);
  const auto clust_index = m_ctx.m_new_table->first_index();
  auto key_buffer = m_thread_ctxs[ctx.m_thread_id]->m_key_buffer;

  if (col->is_multi_value()) {
    ut_a(m_index->is_multi_value());

    auto &mv = ctx.m_mv;

    src_field = dtuple_get_nth_v_field(ctx.m_row.m_ptr, v_col->v_pos);

    if (ctx.m_n_mv_rows_to_add == 0) {
      auto p = m_v_heap.get();

      src_field = innobase_get_computed_value(
          ctx.m_row.m_ptr, v_col, clust_index, &p, key_buffer->heap(), ifield,
          m_ctx.thd(), ctx.m_my_table, m_ctx.m_old_table, nullptr, nullptr);

      m_v_heap.reset(p);

      if (src_field == nullptr) {
        ctx.m_n_rows_added = 0;
        return DB_COMPUTE_VALUE_FAILED;
      } else if (dfield_is_null(src_field)) {
        ctx.m_n_mv_rows_to_add = 1;
      } else if (src_field->len == UNIV_NO_INDEX_VALUE) {
        /* Nothing to be indexed */
        ctx.m_n_rows_added = UNIV_NO_INDEX_VALUE;
        return DB_FAIL;
      } else {
        mv = static_cast<const multi_value_data *>(src_field->data);

        ut_a(mv->num_v > n_added);
        ctx.m_n_mv_rows_to_add = mv->num_v - n_added;

        src_field->len = mv->data_len[n_added];
        src_field->data = const_cast<void *>(mv->datap[n_added]);
      }
    } else {
      src_field->data = const_cast<void *>(mv->datap[n_added]);
      src_field->len = mv->data_len[n_added];
    }
  } else {
    auto p = m_v_heap.get();

    src_field = innobase_get_computed_value(
        ctx.m_row.m_ptr, v_col, clust_index, &p, nullptr, ifield, m_ctx.thd(),
        ctx.m_my_table, m_ctx.m_old_table, nullptr, nullptr);

    m_v_heap.reset(p);

    if (src_field == nullptr) {
      ctx.m_n_rows_added = 0;
      return DB_COMPUTE_VALUE_FAILED;
    }
  }

  return DB_SUCCESS;
}

dberr_t Builder::copy_fts_column(Copy_ctx &ctx, dfield_t *field) noexcept {
  doc_id_t doc_id;
  auto &fts = m_ctx.m_fts;

  if (!fts.m_doc_id->is_generated()) {
    /* Fetch Doc ID if it already exists in the row, and not supplied by
    the caller. Even if the value column is nullptr, we still need to
    get the Doc ID to maintain the correct max Doc ID. */
    doc_id = fts.m_doc_id->fetch(ctx.m_row.m_ptr);

    if (unlikely(doc_id == 0)) {
      ctx.m_n_rows_added = 0;
      ib::warn(ER_IB_MSG_964) << "FTS Doc ID is zero. Record skipped";
      return DB_FAIL;
    }
  } else {
    doc_id = fts.m_doc_id->current();
  }

  ut_a(doc_id <= 4294967295u);

  if (unlikely(!dfield_is_null(field))) {
    auto ptr = ut::malloc_withkey(UT_NEW_THIS_FILE_PSI_KEY,
                                  sizeof(FTS::Doc_item) + field->len);
    auto doc_item = static_cast<FTS::Doc_item *>(ptr);
    auto value = static_cast<byte *>(ptr) + sizeof(*doc_item);

    memcpy(value, field->data, field->len);

    field->data = value;

    doc_item->m_field = field;
    doc_item->m_doc_id = doc_id;

    fts.m_ptr->enqueue(doc_item);
  }

  ctx.m_n_rows_added = 1;

  return DB_SUCCESS;
}

dberr_t Builder::copy_columns(Copy_ctx &ctx, size_t &mv_rows_added,
                              doc_id_t &write_doc_id) noexcept {
  auto &fts = m_ctx.m_fts;
  auto key_buffer = m_thread_ctxs[ctx.m_thread_id]->m_key_buffer;
  auto &fields = key_buffer->m_dtuples[key_buffer->size()];

  const dict_field_t *ifield = m_index->get_field(0);
  auto field = fields = key_buffer->alloc(ctx.m_n_fields);
  const auto page_size = dict_table_page_size(m_ctx.m_old_table);

  for (size_t i = 0; i < ctx.m_n_fields; ++i, ++field, ++ifield) {
    const auto col = ifield->col;
    const auto col_no = dict_col_get_no(col);

    /* Process the Doc ID column. */
    if (likely(fts.m_doc_id == nullptr || !fts.m_doc_id->is_generated() ||
               col_no != m_index->table->fts->doc_col || col->is_virtual())) {
      dfield_t *src_field;

      /* Use callback to get the virtual column value */
      if (col->is_virtual()) {
        auto err =
            get_virtual_column(ctx, ifield, col, src_field, mv_rows_added);
        if (err != DB_SUCCESS) {
          return err;
        }
      } else {
        src_field = dtuple_get_nth_field(ctx.m_row.m_ptr, col_no);
      }

      dfield_copy(field, src_field);

      /* Tokenize and process data for FTS */
      if (unlikely(is_fts_index())) {
        auto err = copy_fts_column(ctx, field);
        if (err != DB_SUCCESS) {
          return err;
        }
        continue;
      }

      if (field->len != UNIV_SQL_NULL && col->mtype == DATA_MYSQL &&
          col->len != field->len) {
        if (m_conv_heap.get() != nullptr) {
          convert(m_ctx.m_old_table->first_index(), src_field, field, col->len,
                  page_size,
                  IF_DEBUG(dict_table_is_sdi(m_ctx.m_old_table->id), )
                      m_conv_heap.get());
        } else if (!dict_table_is_comp(m_index->table)) {
          /* Heap is created when new table is not compact. */
          ib::info(ER_IB_DDL_CONVERT_HEAP_NOT_FOUND);

          DBUG_EXECUTE_IF("ddl_convert_charset_without_heap_fail",
                          { return DB_ERROR; });
          ut_ad(false);
          return DB_ERROR;
        }
      }
    } else {
      fts_add_doc_id(field, ifield, write_doc_id);
    }

    ulint len = dfield_get_len(field);

    if (dfield_is_null(field)) {
      ut_a(!(col->prtype & DATA_NOT_NULL));
      continue;
    } else if (ctx.m_row.m_ext == nullptr) {
      /* Not an externally stored column. */
    } else if (m_index->is_clustered()) {
      /* Flag externally stored fields. */
      const byte *buf = row_ext_lookup(ctx.m_row.m_ext, col_no, &len);

      if (buf != nullptr) {
        ut_a(buf != field_ref_zero);
        if (i < dict_index_get_n_unique(m_index)) {
          dfield_set_data(field, buf, len);
        } else {
          dfield_set_ext(field);
          len = dfield_get_len(field);
        }
      }
    } else if (!col->is_virtual()) {
      /* Only non-virtual column are stored externally */
      const byte *buf = row_ext_lookup(ctx.m_row.m_ext, col_no, &len);

      if (buf != nullptr) {
        ut_a(buf != field_ref_zero);
        dfield_set_data(field, buf, len);
      }
    }

    /* If a column prefix index, take only the prefix */

    if (ifield->prefix_len > 0) {
      len = dtype_get_at_most_n_mbchars(
          col->prtype, col->mbminmaxlen, ifield->prefix_len, len,
          static_cast<char *>(dfield_get_data(field)));

      dfield_set_len(field, len);
    }

    ut_a(len <= col->len || DATA_LARGE_MTYPE(col->mtype) ||
         (col->mtype == DATA_POINT && len == DATA_MBR_LEN));

    auto fixed_len = ifield->fixed_len;

    if (fixed_len > 0 && !dict_table_is_comp(m_index->table) &&
        DATA_MBMINLEN(col->mbminmaxlen) != DATA_MBMAXLEN(col->mbminmaxlen)) {
      /* CHAR in ROW_FORMAT=REDUNDANT is always fixed-length, but
      in the temporary file it is variable-length for variable-length
      character sets. */
      fixed_len = 0;
    }

    if (fixed_len > 0) {
#ifdef UNIV_DEBUG
      const auto mbminlen = DATA_MBMINLEN(col->mbminmaxlen);
      const auto mbmaxlen = DATA_MBMAXLEN(col->mbminmaxlen);

      /* len should be between size calculated base on mbmaxlen and mbminlen
       */
      ut_a(len <= fixed_len);
      ut_a(!mbmaxlen || len >= mbminlen * (fixed_len / mbmaxlen));
      ut_a(!dfield_is_ext(field));
#endif /* UNIV_DEBUG */
    } else if (dfield_is_ext(field)) {
      ctx.m_extra_size += 2;
    } else if (len < 128 || !DATA_BIG_COL(col)) {
      ++ctx.m_extra_size;
    } else {
      /* For variable-length columns, we look up the maximum length from
      the column itself.  If this is a prefix index column shorter than
      256 bytes, this will waste one byte. */
      ctx.m_extra_size += 2;
    }
    ctx.m_data_size += len;
  }

  return DB_SUCCESS;
}

dberr_t Builder::copy_row(Copy_ctx &ctx, size_t &mv_rows_added) noexcept {
  auto key_buffer = m_thread_ctxs[ctx.m_thread_id]->m_key_buffer;
  const auto is_multi_value_index = m_index->is_multi_value();

  ut_a(ctx.m_n_rows_added == 0);

  if (unlikely(key_buffer->full())) {
    return DB_OVERFLOW;
  }

  // clang-format off
  DBUG_EXECUTE_IF(
      "ddl_buf_add_two",
      if (key_buffer->size()>= 2) {
        return DB_OVERFLOW;
      });
  // clang-format on

  /* Create spatial index should not come here. */
  ut_a(!is_spatial_index());

  doc_id_t write_doc_id{};

  for (;;) {
    if (unlikely(key_buffer->full())) {
      return ctx.m_n_rows_added == 0 ? DB_OVERFLOW : DB_SUCCESS;
    }

    // clang-format off
    DBUG_EXECUTE_IF(
        "ddl_add_multi_value",
        if (ctx.m_n_rows_added == 5) {
          return DB_OVERFLOW;
        });
    // clang-format on

    ctx.m_data_size = 0;
    ctx.m_n_fields = dict_index_get_n_fields(m_index);
    ctx.m_extra_size = UT_BITS_IN_BYTES(m_index->n_nullable);

    /* Note: field->data will point to a value on the
    stack: "write_doc_id" after dfield_set_data(). Because
    there is only one doc_id per row, it shouldn't matter.
    We allocate a new buffer before we leave the function
    later below. */

    auto err = copy_columns(ctx, mv_rows_added, write_doc_id);

    if (unlikely(err != DB_SUCCESS)) {
      return err;
    }

    /* If this is an FTS index, we already populated the sort buffer. */
    if (unlikely(is_fts_index())) {
      return DB_SUCCESS;
    }

#ifdef UNIV_DEBUG
    {
      ulint extra;
      auto fields = key_buffer->m_dtuples[key_buffer->size()];

      auto size = rec_get_serialize_size(m_index, fields, ctx.m_n_fields,
                                         nullptr, &extra, MAX_ROW_VERSION);

      ut_a(ctx.m_data_size + ctx.m_extra_size == size);
      ut_a(ctx.m_extra_size == extra);
    }
#endif /* UNIV_DEBUG */

    /* Add to the total size of the record in the output buffer,
    the encoded length of extra_size and the extra bytes (extra_size).
    See Key_sort_buffer::write() for the variable-length encoding
    of extra_size. */
    ctx.m_data_size +=
        (ctx.m_extra_size + 1) + ((ctx.m_extra_size + 1) >= 0x80);

    /* Record size can exceed page size while converting to redundant row
    format. There is an assert ut_ad(size < UNIV_PAGE_SIZE) in
    rec_offs_data_size(). It may hit the assert before attempting to
    insert the row. */
    if (unlikely(m_conv_heap.get() != nullptr &&
                 ctx.m_data_size > UNIV_PAGE_SIZE)) {
      ctx.m_n_rows_added = 0;
      return DB_TOO_BIG_RECORD;
    }

    if (unlikely(!key_buffer->will_fit(ctx.m_data_size))) {
      if (!is_multi_value_index) {
        ctx.m_n_rows_added = 0;
      }
      return DB_OVERFLOW;
    }

    key_buffer->deep_copy(ctx.m_n_fields, ctx.m_data_size);

    /* Note row added and all fields copied. */
    ctx.m_n_fields = 0;
    ++ctx.m_n_rows_added;

    if (m_conv_heap.get() != nullptr) {
      mem_heap_empty(m_conv_heap.get());
    }

    if (ctx.m_n_rows_added < ctx.m_n_mv_rows_to_add) {
      ut_a(is_multi_value_index);
      ++mv_rows_added;

      // clang-format off
      DBUG_EXECUTE_IF(
          "ddl_add_multi_value",
          if (mv_rows_added == 7) {
            return DB_OVERFLOW;
          });
      // clang-format on

      continue;
    }
    break;
  }

  if (is_multi_value_index) {
    mv_rows_added = 0;
  }

  ut_a(ctx.m_n_rows_added > 0 && ctx.m_n_rows_added != UNIV_NO_INDEX_VALUE);
  return DB_SUCCESS;
}

bool Builder::create_file(ddl::file_t &file) noexcept {
  ut_a(!file.m_file.is_open());

  if (ddl::file_create(&file, m_tmpdir)) {
    MONITOR_ATOMIC_INC(MONITOR_ALTER_TABLE_SORT_FILES);
    ut_a(file.m_file.is_open());
    return true;
  } else {
    return false;
  }
}

dberr_t Builder::append(ddl::file_t &file, IO_buffer io_buffer) noexcept {
  auto err = ddl::pwrite(file.m_file.get(), io_buffer.first, io_buffer.second,
                         file.m_size);

  if (err != DB_SUCCESS) {
    set_error(DB_TEMP_FILE_WRITE_FAIL);
    return get_error();
  } else {
    file.m_size += io_buffer.second;
    return err;
  }
}

dberr_t Builder::batch_insert(size_t thread_id,
                              Latch_release &&latch_release) noexcept {
  ut_a(is_spatial_index());

  auto rtree_inserter = m_thread_ctxs[thread_id]->m_rtree_inserter;
  const auto trx_id = m_ctx.m_trx->id;

  return rtree_inserter->batch_insert(trx_id, std::move(latch_release));
}

void Builder::batch_insert_deep_copy_tuples(size_t thread_id) noexcept {
  ut_a(is_spatial_index());
  auto rtree_inserter = m_thread_ctxs[thread_id]->m_rtree_inserter;
  return rtree_inserter->deep_copy_tuples();
}

dberr_t Builder::key_buffer_sort(size_t thread_id) noexcept {
  auto key_buffer = m_thread_ctxs[thread_id]->m_key_buffer;

  if (key_buffer->is_unique()) {
    auto index = key_buffer->m_index;
    Dup dup = {index, m_ctx.m_table, m_ctx.m_col_map, 0};

    key_buffer->sort(&dup);

    if (dup.m_n_dup > 0) {
      set_error(DB_DUPLICATE_KEY);
      return get_error();
    }
  } else {
    key_buffer->sort(nullptr);
  }

  return DB_SUCCESS;
}

dberr_t Builder::online_build_handle_error(dberr_t err) noexcept {
  set_error(err);

  if (m_btr_load != nullptr) {
    /* page_loaders[0] has increased buf_fix_count through release(). This is
    decremented by calling latch(). Similar release() calls for page_loaders at
    non-zero levels are handled in finish() */
    m_btr_load->latch();
    err = m_btr_load->finish(err);

    ut::delete_(m_btr_load);
    m_btr_load = nullptr;
  }

  return get_error();
}

dberr_t Builder::insert_direct(Cursor &cursor, size_t thread_id) noexcept {
  ut_a(m_id == 0);
  ut_ad(is_skip_file_sort());
  ut_a(!is_fts_index());
  ut_a(m_ctx.m_trx->id > 0);
  ut_a(!is_spatial_index());
  ut_a(!srv_read_only_mode);
  ut_a(!dict_index_is_ibuf(m_index));

  {
    auto err = m_ctx.check_state_of_online_build_log();

    DBUG_EXECUTE_IF("builder_insert_direct_trigger_error", {
      static int count = 0;
      ++count;
      if (count > 1) {
        err = DB_ONLINE_LOG_TOO_BIG;
        m_ctx.m_trx->error_key_num = SERVER_CLUSTER_INDEX_ID;
      }
    });

    if (err != DB_SUCCESS) {
      return online_build_handle_error(err);
    }
  }

  DBUG_EXECUTE_IF("builder_insert_direct_no_builder",
                  { static_cast<void>(online_build_handle_error(DB_ERROR)); });

  if (m_btr_load == nullptr) {
    auto ind = index();
    ib::error(ER_IB_MSG_DDL_FAIL_NO_BUILDER, static_cast<unsigned>(get_state()),
              static_cast<unsigned>(get_error()), id(), ind->name(),
              ind->space_id(), static_cast<unsigned>(ind->page),
              ctx().old_table()->name.m_name, ctx().new_table()->name.m_name);
    return DB_ERROR;
  }

  m_btr_load->latch();

  auto thread_ctx = m_thread_ctxs[thread_id];
  auto key_buffer = thread_ctx->m_key_buffer;

  /* Temporary File is not used. Insert sorted block directly into the index. */
  cursor.m_tuple_heap.clear();

  {
    /* Copy the last row for duplicate key check. */
    auto p = cursor.m_tuple_heap.get();
    auto fields = key_buffer->back();

    memcpy(cursor.m_prev_fields, fields, m_ctx.m_n_uniq * sizeof(dfield_t));

    for (size_t i = 0; i < m_ctx.m_n_uniq; ++i) {
      dfield_dup(&cursor.m_prev_fields[i], p);
    }
  }

  m_prev_fields = cursor.m_prev_fields;

  {
    Key_sort_buffer_cursor key_buffer_cursor(this, key_buffer);

    auto err = key_buffer_cursor.open();

    if (err == DB_SUCCESS) {
      err = m_btr_load->build(key_buffer_cursor);

      /* Load didn't return an internal error, check cursor for errors. */
      if (err == DB_SUCCESS) {
        err = key_buffer_cursor.get_err();
      }
    }

    if (cursor.eof() || err != DB_SUCCESS) {
      err = m_btr_load->finish(err);
      ut::delete_(m_btr_load);
      m_btr_load = nullptr;
    } else {
      m_btr_load->release();
    }

    if (err != DB_SUCCESS) {
      return err;
    }
  }

  return DB_SUCCESS;
}

dberr_t Builder::batch_add_row(Row &row, size_t thread_id) noexcept {
  ut_a(is_spatial_index());

  auto key_buffer = m_thread_ctxs[thread_id]->m_key_buffer;
  auto rtree_inserter = m_thread_ctxs[thread_id]->m_rtree_inserter;

  ut_a(rtree_inserter->get_index() == key_buffer->m_index);

  /* If the geometry field is invalid, report error. */
  {
    const auto ind_field = key_buffer->m_index->get_field(0);
    const auto col = ind_field->col;
    auto col_no = dict_col_get_no(col);
    const auto dfield = dtuple_get_nth_field(row.m_ptr, col_no);

    if (dfield_is_null(dfield) ||
        dfield_get_len(dfield) < GEO_DATA_HEADER_SIZE) {
      return DB_CANT_CREATE_GEOMETRY_OBJECT;
    }
  }

  /* Note: This is a shallow copy. */
  rtree_inserter->add_to_batch(row.m_ptr, row.m_ext);

  return DB_SUCCESS;
}

dberr_t Builder::add_to_key_buffer(Copy_ctx &ctx,
                                   size_t &mv_rows_added) noexcept {
  const size_t old_mv_rows_added = mv_rows_added;
  auto err = copy_row(ctx, mv_rows_added);
  auto thread_ctx = m_thread_ctxs[ctx.m_thread_id];
  auto key_buffer = thread_ctx->m_key_buffer;

  if (unlikely(ctx.m_n_rows_added <= 0 || mv_rows_added != 0)) {
    if (unlikely(mv_rows_added != 0)) {
      /* This signals that a partial row was added to the key buffer
      due to reaching its size limit. We need to increment the
      file size by this amount */
      thread_ctx->m_n_recs += (mv_rows_added - old_mv_rows_added);
    }

    if (unlikely(err == DB_COMPUTE_VALUE_FAILED)) {
      set_error(err);
    }

    return err;
  }

  if (unlikely(ctx.m_n_rows_added == UNIV_NO_INDEX_VALUE)) {
    ut_a(err == DB_FAIL);

    /* Nothing to be indexed from current row, skip this index. */
    ut_a(key_buffer->m_index->is_multi_value());
    return DB_SUCCESS;
  }

  /* If we are creating FTS index, a single row can generate multiple
  records for a tokenized word. */
  thread_ctx->m_n_recs += ctx.m_n_rows_added;

  if (unlikely(err != DB_SUCCESS)) {
    ut_a(err == DB_TOO_BIG_RECORD || err == DB_COMPUTE_VALUE_FAILED);
    return err;
  }

  if (unlikely(is_fts_index())) {
    auto &fts = m_ctx.m_fts;

    err = fts.m_ptr->check_for_errors();

    if (unlikely(err != DB_SUCCESS)) {
      return err;
    }
  }

  if (is_skip_file_sort()) {
    ut_a(!key_buffer->empty());
    auto &fields = key_buffer->back();

    ut_ad(m_id == 0);
    ut_ad(key_buffer->is_clustered());

    /* Detect duplicates by comparing the current record with previous record.*/
    if (m_prev_fields != nullptr &&
        Key_sort_buffer::compare(m_prev_fields, fields, &m_clust_dup) == 0) {
      set_error(DB_DUPLICATE_KEY);
      return get_error();
    }

    m_prev_fields = fields;
  }

  return DB_SUCCESS;
}

dberr_t Builder::bulk_add_row(Cursor &cursor, Row &row, size_t thread_id,
                              Latch_release &&latch_release) noexcept {
  /* Non-zero indicates this number of multi-value data have been added to the
  key buffer, and it should just continue from this point, otherwise, this is
  a new row to be added to the key buffer. For the output, non-zero means the
  new number of multi-value data which have been handled, while zero means
  this is a normal row or all data of the multi-value data in this row have
  been parsed. */
  size_t mv_rows_added{};
  auto thread_ctx = m_thread_ctxs[thread_id];
  auto key_buffer = thread_ctx->m_key_buffer;

  do {
    dberr_t err{DB_SUCCESS};
    Copy_ctx ctx{row, m_ctx.m_eval_table, thread_id};

    if (likely(!cursor.eof())) {
      err = add_to_key_buffer(ctx, mv_rows_added);

      if (err != DB_OVERFLOW) {
        return err;
      }
      /* Need to make room, flush the current key buffer to disk and retry. */
    } else if (unlikely(thread_ctx->m_n_recs == 0 && key_buffer->empty())) {
      /* Table is empty. */
      return DB_END_OF_INDEX;
    }

    if (unlikely(is_fts_index() &&
                 (cursor.eof() || !m_ctx.m_fts.m_doc_id->is_generated()))) {
      return DB_SUCCESS;
    }

    ut_ad(m_ctx.m_old_table == m_ctx.m_new_table
              ? !key_buffer->is_clustered()
              : (m_id == 0) == key_buffer->is_clustered());

    if (!key_buffer->empty()) {
      ut_a(err == DB_SUCCESS || err == DB_OVERFLOW);
      err = key_buffer_sort(thread_id);

      if (err != DB_SUCCESS) {
        set_error(err);
        return get_error();
      }

      if (is_skip_file_sort()) {
        if (!cursor.eof()) {
          /* Copy the row data and release any latches held by the parallel
          scan thread. Required for the log_free_check() during mtr.commit(). */
          err = cursor.copy_row(thread_id, row);

          if (err != DB_SUCCESS) {
            set_error(err);
            return get_error();
          }

          err = latch_release();

          if (err != DB_SUCCESS) {
            set_error(err);
            return get_error();
          }
        }

        err = insert_direct(cursor, thread_id);

        key_buffer->clear();

        if (err != DB_SUCCESS) {
          ut_a(m_btr_load == nullptr);
          set_error(err);
          return get_error();
        }

        m_ctx.note_max_trx_id(key_buffer->m_index);

        if (!cursor.eof()) {
          continue;
        }

        ut_a(m_btr_load == nullptr);
        return DB_END_OF_INDEX;
      }
    }

    /* Fulltext index read threads should not write to the temporary file
    directly, @see copy_fts_column(). */
    if (unlikely(key_buffer->is_fts())) {
      return DB_SUCCESS;
    }

    IF_ENABLED("ddl_tmpfile_fail", set_error(DB_OUT_OF_MEMORY);
               return get_error();)

    IF_ENABLED("ddl_ins_spatial_fail", set_error(DB_FAIL); return get_error();)

    if (!thread_ctx->m_file.m_file.is_open()) {
      if (!create_file(thread_ctx->m_file)) {
        set_error(DB_IO_ERROR);
        return get_error();
      }
    }

    IF_ENABLED("ddl_write_failure", set_error(DB_TEMP_FILE_WRITE_FAIL);
               return get_error();)

    auto persistor = [&](IO_buffer io_buffer) -> dberr_t {
      auto &file = thread_ctx->m_file;

      ut_a(!(file.m_size % IO_BLOCK_SIZE));

      os_offset_t n = io_buffer.second;
      ut_a(n != 0);
      ut_a(n % IO_BLOCK_SIZE == 0);

      auto err =
          ddl::pwrite(file.m_file.get(), io_buffer.first, n, file.m_size);

      if (err != DB_SUCCESS) {
        set_error(DB_TEMP_FILE_WRITE_FAIL);
        return get_error();
      }

      file.m_size += n;

      return DB_SUCCESS;
    };

    auto &file = thread_ctx->m_file;

    thread_ctx->m_offsets.push_back(file.m_size);

    auto io_buffer = thread_ctx->m_io_buffer;

    err = key_buffer->serialize(io_buffer, persistor);

    if (err != DB_SUCCESS) {
      return err;
    }

    key_buffer->clear();

    m_ctx.note_max_trx_id(key_buffer->m_index);

  } while (!cursor.eof());

  return DB_END_OF_INDEX;
}

dberr_t Builder::add_row(Cursor &cursor, Row &row, size_t thread_id,
                         Latch_release &&latch_release) noexcept {
  auto err = m_ctx.check_state_of_online_build_log();

  DBUG_EXECUTE_IF("builder_add_row_trigger_error", {
    err = DB_ONLINE_LOG_TOO_BIG;
    m_ctx.m_trx->error_key_num = SERVER_CLUSTER_INDEX_ID;
  });

  if (err != DB_SUCCESS) {
    err = online_build_handle_error(err);
  } else if (is_spatial_index()) {
    if (!cursor.eof()) {
      err = batch_add_row(row, thread_id);
    }
  } else {
    err = bulk_add_row(cursor, row, thread_id, std::move(latch_release));
    clear_virtual_heap();
  }

  return err;
}

void Builder::copy_blobs(const dict_index_t *index, const mrec_t *mrec,
                         const ulint *offsets, const page_size_t &page_size,
                         dtuple_t *tuple,
                         IF_DEBUG(bool is_sdi, ) mem_heap_t *heap) noexcept {
  ut_ad(mrec == nullptr || rec_offs_any_extern(offsets));

  for (size_t i = 0; i < dtuple_get_n_fields(tuple); i++) {
    ulint len;
    const void *data;
    auto field = dtuple_get_nth_field(tuple, i);

    if (likely(!dfield_is_ext(field))) {
      continue;
    }

    ut_ad(!dfield_is_null(field));

    /* During the creation of a PRIMARY KEY, the table is X-locked, and we
    skip copying records that have been marked for deletion. Therefore,
    externally stored columns cannot possibly be freed between the time the
    BLOB pointers are read (Loader::*read()) and dereferenced (below). */
    if (mrec == nullptr) {
      const auto field_data = static_cast<byte *>(dfield_get_data(field));
      const auto field_len = dfield_get_len(field);

      ut_a(field_len >= BTR_EXTERN_FIELD_REF_SIZE);

      ut_a(memcmp(field_data + field_len - BTR_EXTERN_FIELD_REF_SIZE,
                  field_ref_zero, BTR_EXTERN_FIELD_REF_SIZE));

      data = lob::btr_copy_externally_stored_field_func(
          nullptr, index, &len, nullptr, field_data, page_size, field_len,
          IF_DEBUG(is_sdi, ) heap);
    } else {
      data = lob::btr_rec_copy_externally_stored_field_func(
          nullptr, index, mrec, offsets, page_size, i, &len, nullptr,
          IF_DEBUG(is_sdi, ) heap, true);
    }

    /* Because we have locked the table, any records
    written by incomplete transactions must have been
    rolled back already. There must not be any incomplete
    BLOB columns. */
    ut_a(data != nullptr);

    dfield_set_data(field, data, len);
  }
}

dberr_t Builder::dtuple_copy_blobs(dtuple_t *dtuple, ulint *offsets,
                                   const mrec_t *mrec,
                                   mem_heap_t *heap) noexcept {
  const auto old_index = m_ctx.m_old_table->first_index();

  if (m_index->is_clustered() && dict_index_is_online_ddl(old_index)) {
    auto err = row_log_table_get_error(old_index);

    if (err != DB_SUCCESS) {
      return err;
    }
  }

  if (dtuple->has_ext()) {
    ut_a(m_index->is_clustered());

    /* Off-page columns can be fetched safely when concurrent modifications
    to the table are disabled. (Purge can process delete-marked records, but
    Loader::*read() would have skipped them.)

    When concurrent modifications are enabled, Loader::*read() will only
    see rows from transactions that were committed before the ALTER TABLE
    started (REPEATABLE READ).

    Any modifications after the Loader::*read() scan will go through
    row_log_table_apply(). Any modifications to off-page columns will be
    tracked by row_log_table_blob_alloc() and row_log_table_blob_free(). */
    Builder::copy_blobs(old_index, mrec, offsets,
                        dict_table_page_size(m_ctx.m_old_table), dtuple,
                        IF_DEBUG(dict_index_is_sdi(m_index), ) heap);
  }

  ut_ad(dtuple_validate(dtuple));

  return DB_SUCCESS;
}

dberr_t Builder::check_duplicates(Thread_ctxs &dupcheck, Dup *dup) noexcept {
  Merge_cursor cursor(this, nullptr, m_local_stage);
  const auto buffer_size = m_ctx.scan_buffer_size(m_thread_ctxs.size());

  size_t n_files_to_check{};

  for (auto thread_ctx : dupcheck) {
    if (thread_ctx->m_offsets.size() == 1) {
      auto err = cursor.add_file(thread_ctx->m_file, buffer_size.second);

      if (err != DB_SUCCESS) {
        return err;
      }
      ++n_files_to_check;
    }
  }

  auto err = n_files_to_check > 0 ? cursor.open() : DB_END_OF_INDEX;

  if (err != DB_SUCCESS) {
    return err == DB_END_OF_INDEX ? DB_SUCCESS : err;
  }

  dtuple_t *dtuple{};
  auto prev_dtuple = dtuple;
  Scoped_heap prev_tuple_heap;

  /* For secondary indexes we have to compare all the columns for the index,
  this includes the cluster index primary key columns too. */
  Compare_key compare_key(m_index, dup, !m_sort_index->is_clustered());

  const auto n_compare = dict_index_get_n_unique_in_tree(m_index);

  prev_tuple_heap.create(2048, UT_LOCATION_HERE);

  while ((err = cursor.fetch(dtuple)) == DB_SUCCESS) {
    if (prev_dtuple != nullptr) {
      const auto cmp = compare_key(prev_dtuple->fields, dtuple->fields);

      if (cmp > 0) {
        /* Rows are out of order. */
        return DB_CORRUPTION;
      }
      if (cmp == 0) {
        return DB_DUPLICATE_KEY;
      }
    }

    prev_tuple_heap.clear();

    /* Do a deep copy. */
    prev_dtuple = dtuple_copy(dtuple, prev_tuple_heap.get());
    dtuple_set_n_fields_cmp(prev_dtuple, n_compare);

    for (size_t i = 0; i < n_compare; ++i) {
      dfield_dup(&prev_dtuple->fields[i], prev_tuple_heap.get());
    }

    err = cursor.next();

    if (err != DB_SUCCESS) {
      break;
    }
  }

  return err == DB_END_OF_INDEX ? DB_SUCCESS : err;
}

dberr_t Builder::btree_build() noexcept {
  ut_a(!is_skip_file_sort());

  DEBUG_SYNC_C_IF_THD(m_ctx.thd(), "ddl_btree_build_interrupt");
  if (m_local_stage != nullptr) {
    m_local_stage->begin_phase_insert();
  }

  auto observer = m_ctx.m_trx->flush_observer;
  Dup dup = {m_index, m_ctx.m_table, m_ctx.m_col_map, 0};
  Merge_cursor cursor(this, &dup, m_local_stage);
  const auto io_buffer_size = m_ctx.load_io_buffer_size(m_thread_ctxs.size());

  uint64_t total_rows{};
  dberr_t err{DB_SUCCESS};

  for (auto thread_ctx : m_thread_ctxs) {
    if (!thread_ctx->m_file.m_file.is_open()) {
      continue;
    }

    err = cursor.add_file(thread_ctx->m_file, io_buffer_size);

    if (err != DB_SUCCESS) {
      set_error(err);
      return get_error();
    }

    ut_a(thread_ctx->m_n_recs == thread_ctx->m_file.m_n_recs);

    total_rows += thread_ctx->m_n_recs;
  }

  Btree_load btr_load(m_index, m_ctx.m_trx->id, observer);

  dberr_t cursor_err{DB_SUCCESS};

  if (total_rows > 0) {
    err = cursor.open();

    if (err == DB_SUCCESS) {
      err = btr_load.build(cursor);
    } else if (err == DB_END_OF_INDEX) {
      err = DB_SUCCESS;
    }

    cursor_err = cursor.get_err();

    if (cursor_err == DB_END_OF_INDEX) {
      cursor_err = DB_SUCCESS;
    }

    ut_a(err != DB_SUCCESS || total_rows == cursor.get_n_rows());
  }

  /* First we check if the Btree loader returned an internal error.
  If loader succeeded then we check if the cursor returned an error. */
  err = btr_load.finish(err != DB_SUCCESS ? err : cursor_err);

  if (err != DB_SUCCESS) {
    set_error(err);
  }

  set_next_state();

  if (err == DB_SUCCESS) {
    m_loader.add_task(Loader::Task{this});
  }

  return get_error();
}

dberr_t Builder::create_merge_sort_tasks() noexcept {
  ut_a(!is_fts_index());
  ut_a(m_ctx.m_trx->id > 0);
  ut_a(!is_spatial_index());
  ut_a(!srv_read_only_mode);
  ut_a(!dict_index_is_ibuf(m_index));
  ut_a(get_state() == State::SETUP_SORT);

  ut_a(!m_thread_ctxs.empty());

  Thread_ctxs dupcheck{};
  size_t n_runs_to_merge{};
  Dup dup = {m_index, m_ctx.m_table, m_ctx.m_col_map, 0};

  for (auto thread_ctx : m_thread_ctxs) {
    ut_a(thread_ctx->m_file.m_n_recs == 0);
    thread_ctx->m_file.m_n_recs = thread_ctx->m_n_recs;

    n_runs_to_merge += thread_ctx->m_offsets.size();

    /* If there is a single file then there is nothing to merge and the
    file must already be sorted. */
    if (thread_ctx->m_offsets.size() < 2 && is_unique_index()) {
      /* We have to check these files using a merge cursor. */
      dupcheck.push_back(thread_ctx);
    }
  }

  if (!dupcheck.empty()) {
#ifdef UNIV_DEBUG
    {
      size_t n_empty{};
      size_t n_single{};
      size_t n_multiple{};

      for (auto thread_ctx : m_thread_ctxs) {
        if (thread_ctx->m_offsets.empty()) {
          ++n_empty;
        } else if (thread_ctx->m_offsets.size() == 1) {
          ++n_single;
        } else {
          ++n_multiple;
        }
      }
      ut_a(n_single + n_empty == dupcheck.size() ||
           (n_empty == 0 && n_single == dupcheck.size()) ||
           (n_single == 0 && n_multiple + n_empty == dupcheck.size()));
    }
#endif /* UNIV_DEBUG */
    auto err = check_duplicates(dupcheck, &dup);

    if (err != DB_SUCCESS) {
      return err;
    }
  }

  if (m_local_stage != nullptr) {
    m_local_stage->begin_phase_sort(log2(n_runs_to_merge));
  }

  ut_a(m_n_sort_tasks == 0);

  /* Set the next state so that the tasks are executed in the context
  of the next state. */
  set_next_state();

  m_n_sort_tasks.fetch_add(m_thread_ctxs.size(), std::memory_order_relaxed);

  for (auto thread_ctx : m_thread_ctxs) {
    if (thread_ctx->m_key_buffer != nullptr) {
      /* Free up memory that is not going to be used anymore. */
      ut::delete_(thread_ctx->m_key_buffer);
      thread_ctx->m_key_buffer = nullptr;
    }

    m_loader.add_task(Loader::Task{this, thread_ctx->m_id});
  }

  return DB_SUCCESS;
}

void Builder::write_redo(const dict_index_t *index) noexcept {
  ut_ad(!index->table->is_temporary());

  mtr_t mtr;
  mtr.start();

  byte *log_ptr{};

  if (mlog_open(&mtr, 11 + 8, log_ptr)) {
    log_ptr = mlog_write_initial_log_record_low(MLOG_INDEX_LOAD, index->space,
                                                index->page, log_ptr, &mtr);

    mach_write_to_8(log_ptr, index->id);
    mlog_close(&mtr, log_ptr + 8);
  }

  mtr.commit();
}

dberr_t Builder::fts_sort_and_build() noexcept {
  ut_a(is_fts_index());

  auto &fts = m_ctx.m_fts;
  auto err = fts.m_ptr->insert(this);

  for (auto thread_ctx : m_thread_ctxs) {
    thread_ctx->m_file.m_file.close();
  }

  if (fts.m_ptr != nullptr) {
    ut::delete_(fts.m_ptr);
    fts.m_ptr = nullptr;
  }

  if (err != DB_SUCCESS) {
    set_error(err);
    set_next_state();
    return get_error();
  } else {
    set_state(State::FINISH);
    return DB_SUCCESS;
  }
}

dberr_t Builder::finalize() noexcept {
  ut_a(m_ctx.m_need_observer);
  ut_a(get_state() == State::FINISH);

  auto observer = m_ctx.m_trx->flush_observer;

  observer->flush();

  dberr_t err = DB_SUCCESS;
  auto new_table = m_ctx.m_new_table;
  auto space_id =
      new_table != nullptr ? new_table->space : dict_sys_t::s_invalid_space_id;

  Clone_notify notifier(Clone_notify::Type::SPACE_ALTER_INPLACE_BULK, space_id,
                        false);
  if (notifier.failed()) {
    err = DB_ERROR;
  }

  if (err == DB_SUCCESS) {
    write_redo(m_index);

    DEBUG_SYNC(m_ctx.thd(), "row_log_apply_before");

    err = row_log_apply(m_ctx.m_trx, m_index, m_ctx.m_table, m_local_stage);

    DEBUG_SYNC(m_ctx.thd(), "row_log_apply_after");
  }

  if (err != DB_SUCCESS) {
    set_error(err);
  }

  return err;
}

dberr_t Builder::merge_sort(size_t thread_id) noexcept {
  dberr_t err{DB_SUCCESS};
  auto thread_ctx = m_thread_ctxs[thread_id];

  /* If there is a single (or no) list of rows then there is nothing to merge
  and the file must already be sorted. */
  if (thread_ctx->m_file.m_file.is_open() && thread_ctx->m_offsets.size() > 1) {
    Merge_file_sort::Context merge_ctx;
    Dup dup = {m_index, m_ctx.m_table, m_ctx.m_col_map, 0};

    merge_ctx.m_dup = &dup;
    merge_ctx.m_stage = m_local_stage;
    merge_ctx.m_file = &thread_ctx->m_file;
    merge_ctx.m_n_threads = m_thread_ctxs.size();

    Merge_file_sort merge_file_sort{&merge_ctx};

    err = merge_file_sort.sort(this, thread_ctx->m_offsets);

    ut_a(err != DB_SUCCESS ||
         merge_file_sort.get_n_rows() == thread_ctx->m_n_recs);
  }

  const auto n = m_n_sort_tasks.fetch_sub(1, std::memory_order_seq_cst);
  ut_a(n > 0);

  if (err != DB_SUCCESS) {
    set_error(err);
    set_next_state();
  } else if (n == 1 && get_state() == State::SORT) {
    set_next_state();
    m_loader.add_task(Loader::Task{this});
  }

  return get_error();
}

dberr_t Builder::setup_sort() noexcept {
  ut_a(!is_skip_file_sort());
  ut_a(get_state() == State::SETUP_SORT);

  DEBUG_SYNC(m_ctx.thd(), "ddl_merge_sort_interrupt");

  const auto err = create_merge_sort_tasks();

  if (err != DB_SUCCESS) {
    set_error(err);
    return get_error();
  } else {
    return DB_SUCCESS;
  }
}

dberr_t Builder::finish() noexcept {
  if (get_error() != DB_SUCCESS) {
    set_next_state();
    return get_error();
  }

  ut_a(m_n_sort_tasks == 0);
  ut_a(get_state() == State::FINISH);

  for (auto thread_ctx : m_thread_ctxs) {
    thread_ctx->m_file.m_file.close();
  }

  dberr_t err{DB_SUCCESS};

  if (get_error() != DB_SUCCESS || !m_ctx.m_online) {
    /* Do not apply any online log. */
  } else if (m_ctx.m_old_table != m_ctx.m_new_table) {
    ut_a(!m_index->online_log);
    ut_a(m_index->online_status == ONLINE_INDEX_COMPLETE);

    auto observer = m_ctx.m_trx->flush_observer;
    observer->flush();

  } else {
    err = finalize();

    if (err != DB_SUCCESS) {
      set_error(err);
    }
  }

  set_next_state();

  return get_error();
}

void Builder::fallback_to_single_thread() noexcept {
  for (size_t i = 0; i < m_thread_ctxs.size(); ++i) {
    if (i > 0) {
      ut::delete_(m_thread_ctxs[i]);
      m_thread_ctxs[i] = nullptr;
    }
  }
  m_thread_ctxs.resize(1);
}

void Builder::set_next_state() noexcept {
  if (get_error() != DB_SUCCESS) {
    set_state(State::ERROR);
    return;
  }

  switch (get_state()) {
    case State::INIT:
      set_state(State::ADD);
      break;

    case State::ADD:
      if (is_fts_index()) {
        set_state(State::FTS_SORT_AND_BUILD);
      } else if (!is_skip_file_sort()) {
        set_state(State::SETUP_SORT);
      } else {
        set_state(State::FINISH);
        break;
      }
      break;

    case State::SETUP_SORT:
      set_state(State::SORT);
      break;

    case State::SORT:
      set_state(State::BTREE_BUILD);
      break;

    case State::BTREE_BUILD:
      set_state(State::FINISH);
      break;

    case State::FTS_SORT_AND_BUILD:
      set_state(State::FINISH);
      break;

    case State::FINISH:
      set_state(State::STOP);
      break;

    case State::STOP:
    case State::ERROR:
      ut_error;
  }
}

dberr_t Loader::Task::operator()() noexcept {
  dberr_t err;

  switch (m_builder->get_state()) {
    case Builder::State::SETUP_SORT:
      ut_a(!m_builder->is_skip_file_sort());
      err = m_builder->setup_sort();
      break;

    case Builder::State::SORT:
      ut_a(!m_builder->is_skip_file_sort());
      err = m_builder->merge_sort(m_thread_id);
      break;

    case Builder::State::BTREE_BUILD:
      err = m_builder->btree_build();
      break;

    case Builder::State::FTS_SORT_AND_BUILD:
      ut_a(m_builder->is_fts_index());
      err = m_builder->fts_sort_and_build();
      break;

    case Builder::State::FINISH:
      err = m_builder->finish();
      break;

    case Builder::State::ERROR:
      err = m_builder->get_error();
      break;

    case Builder::State::ADD:
    case Builder::State::INIT:
    case Builder::State::STOP:
    default:
      ut_error;
  }

  return err;
}

}  // namespace ddl
