row0row.h

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/** @file include/row0row.h
 General row routines
 
 Created 4/20/1996 Heikki Tuuri
 *******************************************************/
 
#ifndef row0row_h
#define row0row_h
 
#include "btr0types.h"
#include "data0data.h"
#include "dict0types.h"
#include "mtr0mtr.h"
#include "que0types.h"
#include "rem0types.h"
#include "row0types.h"
#include "trx0types.h"
#include "univ.i"
 
/** Gets the offset of the DB_TRX_ID field, in bytes relative to the origin of
a clustered index record.
@param[in] index Clustered index.
@param[in] offsets rec_get_offsets(rec, index).
@return offset of DATA_TRX_ID */
[[nodiscard]] static inline ulint row_get_trx_id_offset(
    const dict_index_t *index, const ulint *offsets);
/** Reads the trx id field from a clustered index record.
@param[in] rec Record.
@param[in] index Clustered index.
@param[in] offsets rec_get_offsets(rec, index).
@return value of the field */
[[nodiscard]] static inline trx_id_t row_get_rec_trx_id(
    const rec_t *rec, const dict_index_t *index, const ulint *offsets);
/** Reads the roll pointer field from a clustered index record.
@param[in] rec Record.
@param[in] index Clustered index.
@param[in] offsets rec_get_offsets(rec, index).
@return value of the field */
[[nodiscard]] static inline roll_ptr_t row_get_rec_roll_ptr(
    const rec_t *rec, const dict_index_t *index, const ulint *offsets);
 
/* Flags for row build type. */
/** build index row */
constexpr uint32_t ROW_BUILD_NORMAL = 0;
/** build row for purge. */
constexpr uint32_t ROW_BUILD_FOR_PURGE = 1;
/** build row for undo. */
constexpr uint32_t ROW_BUILD_FOR_UNDO = 2;
/** build row for insert. */
constexpr uint32_t ROW_BUILD_FOR_INSERT = 3;
/** When an insert or purge to a table is performed, this function builds
the entry to be inserted into or purged from an index on the table.
@param[in] row   Row which should be inserted or purged.
@param[in] ext   Externally stored column prefixes, or nullptr.
@param[in] index Index on the table.
@param[in] heap  Memory heap from which the memory for the index entry is
allocated.
@param[in] flag  ROW_BUILD_NORMAL, ROW_BUILD_FOR_PURGE or ROW_BUILD_FOR_UNDO.
@return index entry which should be inserted or purged
@retval NULL if the externally stored columns in the clustered index record
are unavailable and ext != nullptr, or row is missing some needed columns. */
[[nodiscard]] dtuple_t *row_build_index_entry_low(const dtuple_t *row,
                                                  const row_ext_t *ext,
                                                  const dict_index_t *index,
                                                  mem_heap_t *heap, ulint flag);
/** When an insert or purge to a table is performed, this function builds
the entry to be inserted into or purged from an index on the table.
@return index entry which should be inserted or purged, or NULL if the
externally stored columns in the clustered index record are
unavailable and ext != nullptr
@param[in] row   Row which should be inserted or purged.
@param[in] ext   Externally stored column prefixes, or nullptr.
@param[in] index Index on the table.
@param[in] heap  Memory heap from which the memory for the index entry is
allocated. */
[[nodiscard]] static inline dtuple_t *row_build_index_entry(
    const dtuple_t *row, const row_ext_t *ext, const dict_index_t *index,
    mem_heap_t *heap);
/** An inverse function to row_build_index_entry. Builds a row from a
record in a clustered index.
@param[in] type      ROW_COPY_POINTERS or ROW_COPY_DATA; the latter copies also
the data fields to heap while the first only places pointers to data fields on
the index page, and thus is more efficient.
@param[in] index     Clustered index.
@param[in] rec       Record in the clustered index; NOTE: in the case
ROW_COPY_POINTERS the data fields in the row will point directly into this
record, therefore, the buffer page of this record must be at least s-latched and
the latch held as long as the row dtuple is used!
@param[in] offsets rec_get_offsets(rec,index) or nullptr, in which case this
function will invoke rec_get_offsets().
@param[in] col_table Table, to check which externally stored columns occur in
the ordering columns of an index, or nullptr if index->table should be consulted
instead; the user columns in this table should be the same columns as in
index->table.
@param[in] add_cols  Default values of added columns, or nullptr.
@param[in] col_map   Mapping of old column numbers to new ones, or nullptr.
@param[out] ext      cache of externally stored column prefixes, or nullptr.
@param[in] heap      Memory heap from which the memory needed is allocated.
@return own: row built; see the NOTE below! */
dtuple_t *row_build(ulint type, const dict_index_t *index, const rec_t *rec,
                    const ulint *offsets, const dict_table_t *col_table,
                    const dtuple_t *add_cols, const ulint *col_map,
                    row_ext_t **ext, mem_heap_t *heap);
 
/** An inverse function to row_build_index_entry. Builds a row from a
record in a clustered index, with possible indexing on ongoing
addition of new virtual columns.
@param[in]      type            ROW_COPY_POINTERS or ROW_COPY_DATA;
@param[in]      index           clustered index
@param[in]      rec             record in the clustered index
@param[in]      offsets         rec_get_offsets(rec,index) or NULL
@param[in]      col_table       table, to check which
                                externally stored columns
                                occur in the ordering columns
                                of an index, or NULL if
                                index->table should be
                                consulted instead
@param[in]      add_cols        default values of added columns, or NULL
@param[in]      add_v           new virtual columns added
                                along with new indexes
@param[in]      col_map         mapping of old column
                                numbers to new ones, or NULL
@param[in]      ext             cache of externally stored column
                                prefixes, or NULL
@param[in]      heap            memory heap from which
                                the memory needed is allocated
@return own: row built */
dtuple_t *row_build_w_add_vcol(ulint type, const dict_index_t *index,
                               const rec_t *rec, const ulint *offsets,
                               const dict_table_t *col_table,
                               const dtuple_t *add_cols,
                               const dict_add_v_col_t *add_v,
                               const ulint *col_map, row_ext_t **ext,
                               mem_heap_t *heap);
 
/** Converts an index record to a typed data tuple.
 @return index entry built; does not set info_bits, and the data fields
 in the entry will point directly to rec */
[[nodiscard]] dtuple_t *row_rec_to_index_entry_low(
    const rec_t *rec,          /*!< in: record in the index */
    const dict_index_t *index, /*!< in: index */
    const ulint *offsets,      /*!< in: rec_get_offsets(rec, index) */
    mem_heap_t *heap);         /*!< in: memory heap from which
                              the memory needed is allocated */
/** Converts an index record to a typed data tuple. NOTE that externally
 stored (often big) fields are NOT copied to heap.
 @return own: index entry built */
[[nodiscard]] dtuple_t *row_rec_to_index_entry(
    const rec_t *rec,          /*!< in: record in the index */
    const dict_index_t *index, /*!< in: index */
    const ulint *offsets,      /*!< in/out: rec_get_offsets(rec) */
    mem_heap_t *heap);         /*!< in: memory heap from which
                              the memory needed is allocated */
/** Builds from a secondary index record a row reference with which we can
 search the clustered index record.
 @return own: row reference built; see the NOTE below! */
[[nodiscard]] dtuple_t *row_build_row_ref(
    ulint type,                /*!< in: ROW_COPY_DATA, or ROW_COPY_POINTERS:
                               the former copies also the data fields to
                               heap, whereas the latter only places pointers
                               to data fields on the index page */
    const dict_index_t *index, /*!< in: secondary index */
    const rec_t *rec,          /*!< in: record in the index;
                               NOTE: in the case ROW_COPY_POINTERS
                               the data fields in the row will point
                               directly into this record, therefore,
                               the buffer page of this record must be
                               at least s-latched and the latch held
                               as long as the row reference is used! */
    mem_heap_t *heap);         /*!< in: memory heap from which the memory
                              needed is allocated */
 
/** Builds from a secondary index record a row reference with which we can
search the clustered index record.
@param[in,out] ref Row reference built; see the note below!
@param[in,out] rec Record in the index; note: the data fields in ref will point
directly into this record, therefore, the buffer page of this record must be at
least s-latched and the latch held as long as the row reference is used!
@param[in] index Secondary index
@param[in] offsets Rec_get_offsets(rec, index) or null */
void row_build_row_ref_in_tuple(dtuple_t *ref, const rec_t *rec,
                                const dict_index_t *index, ulint *offsets);
 
/** Builds from a secondary index record a row reference with which we can
search the clustered index record.
@param[in,out]  ref     typed data tuple where the reference is built
@param[in]      map     array of field numbers in rec telling how ref should
                        be built from the fields of rec
@param[in]      rec     record in the index; must be preserved while ref is
                        used, as we do not copy field values to heap
@param[in]      offsets array returned by rec_get_offsets() */
static inline void row_build_row_ref_fast(dtuple_t *ref, const ulint *map,
                                          const rec_t *rec,
                                          const ulint *offsets);
 
/** Searches the clustered index record for a row, if we have the row
 reference.
 @return true if found */
[[nodiscard]] bool row_search_on_row_ref(
    btr_pcur_t *pcur,    /*!< out: persistent cursor, which
            must be closed by the caller */
    ulint mode,          /*!< in: BTR_MODIFY_LEAF, ... */
    dict_table_t *table, /*!< in: table */
    const dtuple_t *ref, /*!< in: row reference */
    mtr_t *mtr);         /*!< in/out: mtr */
/** Fetches the clustered index record for a secondary index record. The latches
 on the secondary index record are preserved.
 @return record or NULL, if no record found */
[[nodiscard]] rec_t *row_get_clust_rec(
    ulint mode,                 /*!< in: BTR_MODIFY_LEAF, ... */
    const rec_t *rec,           /*!< in: record in a secondary index */
    const dict_index_t *index,  /*!< in: secondary index */
    dict_index_t **clust_index, /*!< out: clustered index */
    mtr_t *mtr);                /*!< in: mtr */
 
/** Parse the integer data from specified data, which could be
DATA_INT, DATA_FLOAT or DATA_DOUBLE. If the value is less than 0
and the type is not unsigned then we reset the value to 0
@param[in]      data            data to read
@param[in]      len             length of data
@param[in]      mtype           mtype of data
@param[in]      unsigned_type   if the data is unsigned
@return the integer value from the data */
inline uint64_t row_parse_int(const byte *data, ulint len, ulint mtype,
                              bool unsigned_type);
 
/** Parse the integer data from specified field, which could be
DATA_INT, DATA_FLOAT or DATA_DOUBLE. We could return 0 if
1) the value is less than 0 and the type is not unsigned
or 2) the field is null.
@param[in]      field           field to read the int value
@return the integer value read from the field, 0 for negative signed
int or NULL field */
uint64_t row_parse_int_from_field(const dfield_t *field);
 
/** Read the autoinc counter from the clustered index row.
@param[in]      row     row to read the autoinc counter
@param[in]      n       autoinc counter is in the nth field
@return the autoinc counter read */
uint64_t row_get_autoinc_counter(const dtuple_t *row, ulint n);
 
/** Result of row_search_index_entry */
enum row_search_result {
  ROW_FOUND = 0,      /*!< the record was found */
  ROW_NOT_FOUND,      /*!< record not found */
  ROW_BUFFERED,       /*!< one of BTR_INSERT, BTR_DELETE, or
                      BTR_DELETE_MARK was specified, the
                      secondary index leaf page was not in
                      the buffer pool, and the operation was
                      enqueued in the insert/delete buffer */
  ROW_NOT_DELETED_REF /*!< BTR_DELETE was specified, and
                      row_purge_poss_sec() failed */
};
 
/** Searches an index record.
 @return whether the record was found or buffered */
[[nodiscard]] enum row_search_result row_search_index_entry(
    dict_index_t *index,   /*!< in: index */
    const dtuple_t *entry, /*!< in: index entry */
    ulint mode,            /*!< in: BTR_MODIFY_LEAF, ... */
    btr_pcur_t *pcur,      /*!< in/out: persistent cursor, which must
                           be closed by the caller */
    mtr_t *mtr);           /*!< in: mtr */
 
constexpr uint32_t ROW_COPY_DATA = 1;
constexpr uint32_t ROW_COPY_POINTERS = 2;
 
/* The allowed latching order of index records is the following:
(1) a secondary index record ->
(2) the clustered index record ->
(3) rollback segment data for the clustered index record. */
 
/** Formats the raw data in "data" (in InnoDB on-disk format) using
 "dict_field" and writes the result to "buf".
 Not more than "buf_size" bytes are written to "buf".
 The result is always NUL-terminated (provided buf_size is positive) and the
 number of bytes that were written to "buf" is returned (including the
 terminating NUL).
 @return number of bytes that were written */
[[nodiscard]] ulint row_raw_format(
    const char *data,               /*!< in: raw data */
    ulint data_len,                 /*!< in: raw data length
                                    in bytes */
    const dict_field_t *dict_field, /*!< in: index field */
    char *buf,                      /*!< out: output buffer */
    ulint buf_size);                /*!< in: output buffer size
                                   in bytes */
 
/** Class to build a series of entries based on one multi-value field.
It assumes that there is only one multi-value field on multi-value index. */
class Multi_value_entry_builder {
 public:
  /** Constructor */
  Multi_value_entry_builder(dict_index_t *index, dtuple_t *entry, bool selected)
      : m_index(index),
        m_selected(selected),
        m_entry(entry),
        m_pos(0),
        m_mv_data(nullptr),
        m_mv_field_no(0) {}
 
  virtual ~Multi_value_entry_builder() = default;
 
  /** Get the first index entry. If the multi-value field on the index
  is null, then it's the entry including the null field, otherwise,
  it should be the entry with  multi-value data at the 'pos' position.
  @param[in]    pos     position of the multi-value array, default value
                        will always start from 0
  @return the first index entry to handle, the one including null
  multi-value field, or the  multi-value data at the 'pos' position */
  dtuple_t *begin(uint32_t pos = 0) {
    if (!prepare_multi_value_field()) {
      return (nullptr);
    }
 
    prepare_entry_if_necessary();
    ut_ad(m_entry != nullptr);
 
    m_pos = pos;
    return (m_mv_data == nullptr ? m_entry : next());
  }
 
  /** Get next index entry based on next multi-value data.
  If the previous value is null, then always no next.
  @return next index entry, or nullptr if no more multi-value data */
  dtuple_t *next() {
    if (m_mv_data == nullptr || m_pos >= m_mv_data->num_v) {
      return (nullptr);
    }
 
    ut_ad(m_entry != nullptr);
    dfield_t *field = dtuple_get_nth_field(m_entry, m_mv_field_no);
    ut_ad(dfield_is_multi_value(field));
 
    if (m_selected && (skip() == m_mv_data->num_v)) {
      return (nullptr);
    }
 
    const auto len = m_mv_data->data_len[m_pos];
    dfield_set_data(field, m_mv_data->datap[m_pos], len);
 
    ++m_pos;
    return (m_entry);
  }
 
  /** Get the position of last generated multi-value data
  @return the position */
  uint32_t last_multi_value_position() const {
    return (m_pos > 0 ? m_pos - 1 : 0);
  }
 
 protected:
  /** Find the multi-value field from the passed in entry or row.
  m_mv_field_no should be set once the multi-value field found.
  @return the multi-value field pointer, or nullptr if not found */
  virtual dfield_t *find_multi_value_field() = 0;
 
  /** Prepare the corresponding multi-value field from the row.
  This function will set the m_mv_data if the proper field found.
  @return true if the multi-value field with data on index found,
  otherwise, false */
  virtual bool prepare_multi_value_field() {
    dfield_t *field = find_multi_value_field();
 
    if (field == nullptr || field->len == UNIV_NO_INDEX_VALUE) {
      return (false);
    }
 
    ut_ad(m_mv_field_no > 0);
    ut_ad(dfield_is_multi_value(field));
 
    --m_mv_field_no;
 
    if (!dfield_is_null(field)) {
      m_mv_data = static_cast<multi_value_data *>(field->data);
    }
 
    return (true);
  }
 
  /** Prepare the entry when the entry is not passed in */
  virtual void prepare_entry_if_necessary() { return; }
 
  /** Skip the not selected values and stop m_pos at the next selected one
  @return the next valid value position, or size of m_mv_data to indicate
  there is no more valid value */
  virtual uint32_t skip() {
    ut_ad(m_mv_data != nullptr);
    ut_ad(m_selected);
    return (m_mv_data->num_v);
  }
 
 protected:
  /** Based on which index to build the entry */
  dict_index_t *m_index;
 
  /** True if only the selected(bitmap set) multi-value data would be
  used to build the entries, otherwise false. */
  const bool m_selected;
 
  /** Entry built for the index */
  dtuple_t *m_entry;
 
  /** Multi-value data position */
  uint32_t m_pos;
 
  /** Multi-value data */
  const multi_value_data *m_mv_data;
 
  /** Field number of multi-value data on the index */
  uint32_t m_mv_field_no;
};
 
/** The subclass of the multi-value entry builder, for non-INSERT cases,
With this class, there should be no need to build separate entries for
different values in the same multi-value field. */
class Multi_value_entry_builder_normal : public Multi_value_entry_builder {
 public:
  /** Constructor
  @param[in]            row             based on which complete row to build
                                        the index row
  @param[in]            ext             externally stored column prefixes of
                                        the row
  @param[in,out]        index           multi-value index
  @param[in,out]        heap            memory heap
  @param[in]            check           true if type can be checked, otherwise
                                        skip checking
  @param[in]            selected        true if only the selected(bitmap set)
                                        multi-value data would be used to build
                                        the entries, otherwise false. */
  Multi_value_entry_builder_normal(const dtuple_t *row, const row_ext_t *ext,
                                   dict_index_t *index, mem_heap_t *heap,
                                   bool check, bool selected)
      : Multi_value_entry_builder(index, nullptr, selected),
        m_row(row),
        m_ext(ext),
        m_heap(heap),
        m_check(check) {}
 
 private:
  /** Find the multi-value field from the passed in entry or row.
  m_mv_field_no should be set once the multi-value field found.
  @return the multi-value field pointer, or nullptr if not found */
  dfield_t *find_multi_value_field() override;
 
  /** Prepare the entry when the entry is not passed in */
  void prepare_entry_if_necessary() override {
    if (m_check) {
      m_entry = row_build_index_entry(m_row, m_ext, m_index, m_heap);
    } else {
      /* If not check, then it's basically coming from purge. And actually,
      for multi-value index, this flag really doesn't matter. */
      m_entry = row_build_index_entry_low(m_row, m_ext, m_index, m_heap,
                                          ROW_BUILD_FOR_PURGE);
    }
  }
 
  /** Skip the not selected values and stop m_pos at the next selected one
  @return the next valid value position, or size of m_mv_data to indicate
  there is no more valid value */
  uint32_t skip() override {
    ut_ad(m_selected);
 
    if (m_mv_data->bitset == nullptr) {
      return (m_pos);
    }
 
    while (m_pos < m_mv_data->num_v && !m_mv_data->bitset->test(m_pos)) {
      ++m_pos;
    }
 
    return (m_pos);
  }
 
 private:
  /** Based on which complete row to build the index row */
  const dtuple_t *m_row;
 
  /** Externally stored column prefixes, or nullptr */
  const row_ext_t *m_ext;
 
  /** Memory heap */
  mem_heap_t *m_heap;
 
  /** True if dfield type should be checked, otherwise false */
  const bool m_check;
};
 
/** The subclass of the multi-value row builder, for INSERT cases.
It simply replace the pointers to the multi-value field data for
each different value */
class Multi_value_entry_builder_insert : public Multi_value_entry_builder {
 public:
  /** Constructor
  @param[in,out]        index   multi-value index
  @param[in]            entry   entry to insert based on the index */
  Multi_value_entry_builder_insert(dict_index_t *index, dtuple_t *entry)
      : Multi_value_entry_builder(index, entry, false) {}
 
 private:
  /** Find the multi-value field from the passed entry in or row.
  m_mv_field_no should be set once the multi-value field found.
  @return the multi-value field pointer, or nullptr if not found */
  dfield_t *find_multi_value_field() override {
    uint16_t i = 0;
    dfield_t *field = nullptr;
 
    ut_ad(m_entry != nullptr);
 
    m_mv_field_no = 0;
    for (; i < m_entry->n_fields; ++i) {
      field = &m_entry->fields[i];
      if (!dfield_is_multi_value(field)) {
        continue;
      }
 
      m_mv_field_no = i + 1;
      break;
    }
 
    return (i == m_entry->n_fields ? nullptr : field);
  }
};
 
#include "row0row.ic"
 
#endif