zlob0first.h

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#ifndef zlob0first_h
#define zlob0first_h
 
#include "fil0types.h"
#include "fut0lst.h"
#include "lob0impl.h"
#include "univ.i"
 
namespace lob {
 
/** The first page of an zlob. */
struct z_first_page_t {
  /** Version information. One byte. */
  static const ulint OFFSET_VERSION = FIL_PAGE_DATA;
 
  /** One byte of flag bits.  Currently only one bit (the least
  significant bit) is used, other 7 bits are available for future use.*/
  static const ulint OFFSET_FLAGS = FIL_PAGE_DATA + 1;
 
  /** LOB version. 4 bytes.*/
  static const uint32_t OFFSET_LOB_VERSION = OFFSET_FLAGS + 1;
 
  /** The last transaction that modified this LOB. */
  static const ulint OFFSET_LAST_TRX_ID = OFFSET_LOB_VERSION + 4;
 
  /** The last transaction that modified this LOB. */
  static const ulint OFFSET_LAST_UNDO_NO = OFFSET_LAST_TRX_ID + 6;
 
  /** The length of compressed data stored in this page. */
  static const ulint OFFSET_DATA_LEN = OFFSET_LAST_UNDO_NO + 4;
 
  /** The transaction that created data in the data portion. */
  static const ulint OFFSET_TRX_ID = OFFSET_DATA_LEN + 4;
 
  /** The next index page. */
  static const ulint OFFSET_INDEX_PAGE_NO = OFFSET_TRX_ID + 6;
 
  /** The next frag nodes page. */
  static const ulint OFFSET_FRAG_NODES_PAGE_NO = OFFSET_INDEX_PAGE_NO + 4;
 
  /** List of free index entries. */
  static const ulint OFFSET_FREE_LIST = OFFSET_FRAG_NODES_PAGE_NO + 4;
 
  /** List of index entries. */
  static const ulint OFFSET_INDEX_LIST = OFFSET_FREE_LIST + FLST_BASE_NODE_SIZE;
 
  /** List of free frag entries. */
  static const ulint OFFSET_FREE_FRAG_LIST =
      OFFSET_INDEX_LIST + FLST_BASE_NODE_SIZE;
 
  /** List of frag entries. */
  static const ulint OFFSET_FRAG_LIST =
      OFFSET_FREE_FRAG_LIST + FLST_BASE_NODE_SIZE;
 
  /** Begin of index entries. */
  static const ulint OFFSET_INDEX_BEGIN =
      OFFSET_FRAG_LIST + FLST_BASE_NODE_SIZE;
 
  /** Given the page size, what is the number of index entries the
  first page can contain. */
  ulint get_n_index_entries() const;
 
  /** Given the page size, what is the number of frag entries the
  first page can contain. */
  ulint get_n_frag_entries() const;
 
  ulint size_of_index_entries() const;
 
  ulint size_of_frag_entries() const {
    return (z_frag_entry_t::SIZE * get_n_frag_entries());
  }
 
  ulint begin_frag_entries() const {
    return (OFFSET_INDEX_BEGIN + size_of_index_entries());
  }
 
  ulint begin_data() const {
    return (begin_frag_entries() + size_of_frag_entries());
  }
 
  bool is_empty() const {
    flst_base_node_t *flst = index_list();
    return (flst_get_len(flst) == 0);
  }
 
  /** Get the length of the index list.
  @return length of the index list. */
  ulint get_index_list_length() const {
    flst_base_node_t *flst = index_list();
    return (flst_get_len(flst));
  }
 
  void set_version_0() {
    mlog_write_ulint(frame() + OFFSET_VERSION, 0, MLOG_1BYTE, m_mtr);
  }
 
  byte *begin_data_ptr() const { return (frame() + begin_data()); }
 
  /** Amount of zlob data that can be stored in first page (in bytes). */
  ulint payload() {
    page_size_t page_size(dict_table_page_size(m_index->table));
    ut_ad(begin_data() + FIL_PAGE_DATA_END < page_size.physical());
    return (page_size.physical() - begin_data() - FIL_PAGE_DATA_END);
  }
 
  z_first_page_t() : m_block(nullptr), m_mtr(nullptr), m_index(nullptr) {}
 
  z_first_page_t(mtr_t *mtr, dict_index_t *index)
      : m_block(nullptr), m_mtr(mtr), m_index(index) {}
 
  z_first_page_t(buf_block_t *block) : m_block(block) {}
 
  z_first_page_t(buf_block_t *block, mtr_t *mtr, dict_index_t *index)
      : m_block(block), m_mtr(mtr), m_index(index) {}
 
  buf_block_t *alloc(bool bulk);
 
  void import(trx_id_t trx_id);
 
  page_type_t get_page_type() const {
    return (mach_read_from_2(frame() + FIL_PAGE_TYPE));
  }
 
  /** Load the given page number as the first page in x-latch mode.
  @param[in]    page_no         the first page number.
  @return       the buffer block of the given page number. */
  buf_block_t *load_x(page_no_t page_no) {
    page_id_t page_id(dict_index_get_space(m_index), page_no);
    page_size_t page_size(dict_table_page_size(m_index->table));
    m_block =
        buf_page_get(page_id, page_size, RW_X_LATCH, UT_LOCATION_HERE, m_mtr);
    return (m_block);
  }
 
  /** Load the first page using given mini-transaction. The first page must
  already be x-latched by the m_mtr.
  @param[in]    mtr   the mini-transaction in which first page is to be loaded.
  @return the buffer block of first page. */
  buf_block_t *load_x(mtr_t *mtr) const {
    ut_ad(mtr_memo_contains(m_mtr, m_block, MTR_MEMO_PAGE_X_FIX));
    buf_block_t *tmp = buf_page_get(m_block->page.id, m_index->get_page_size(),
                                    RW_X_LATCH, UT_LOCATION_HERE, mtr);
    ut_ad(tmp == m_block);
    return (tmp);
  }
 
  /** Load the first page of the compressed LOB with x-latch.
  @param[in]   page_id   the page identifier of first page
  @param[in]   page_size the page size information of table.
  @return buffer block of the first page. */
  buf_block_t *load_x(const page_id_t &page_id, const page_size_t &page_size);
 
  /** Load the given page number as the first page in s-latch mode.
  @param[in]    page_no         the first page number.
  @return       the buffer block of the given page number. */
  buf_block_t *load_s(page_no_t page_no) {
    ut_ad(m_block == nullptr);
 
    page_id_t page_id(dict_index_get_space(m_index), page_no);
    page_size_t page_size(dict_table_page_size(m_index->table));
    m_block =
        buf_page_get(page_id, page_size, RW_S_LATCH, UT_LOCATION_HERE, m_mtr);
    return (m_block);
  }
 
  /** Deallocate the first page of a compressed LOB. */
  void dealloc();
 
  /** Set the FIL_PAGE_NEXT to FIL_NULL. */
  void set_next_page_null() { set_next_page_no(FIL_NULL, m_mtr); }
 
  /** Set the FIL_PAGE_PREV to FIL_NULL. */
  void set_prev_page_null() { set_prev_page_no(FIL_NULL, m_mtr); }
 
  /** Set the FIL_PAGE_NEXT to the given value.
  @param[in]    page_no   the page number to set in FIL_PAGE_NEXT.
  @param[in]    mtr       mini trx to be used for this modification. */
  void set_next_page_no(page_no_t page_no, mtr_t *mtr) {
    ut_ad(mtr != nullptr);
    mlog_write_ulint(frame() + FIL_PAGE_NEXT, page_no, MLOG_4BYTES, mtr);
  }
 
  /** Set the FIL_PAGE_PREV to the given value.
  @param[in]    page_no   the page number to set in FIL_PAGE_PREV.
  @param[in]    mtr       mini trx to be used for this modification. */
  void set_prev_page_no(page_no_t page_no, mtr_t *mtr) {
    ut_ad(mtr != nullptr);
    mlog_write_ulint(frame() + FIL_PAGE_PREV, page_no, MLOG_4BYTES, mtr);
  }
 
  /** Write the space identifier to the page header, without generating
  redo log records.
  @param[in]    space_id        the space identifier. */
  void set_space_id_no_redo(space_id_t space_id) {
    mlog_write_ulint(frame() + FIL_PAGE_SPACE_ID, space_id, MLOG_4BYTES,
                     nullptr);
  }
 
  void init() {
    ut_ad(m_mtr != nullptr);
 
    set_page_type();
    set_version_0();
    set_data_len(0);
    set_next_page_null();
    set_prev_page_null();
    set_trx_id(0);
    flst_base_node_t *flst = free_list();
    flst_init(flst, m_mtr);
    flst_base_node_t *ilst = index_list();
    flst_init(ilst, m_mtr);
    flst_base_node_t *free_frag_lst = free_frag_list();
    flst_init(free_frag_lst, m_mtr);
    flst_base_node_t *frag_lst = frag_list();
    flst_init(frag_lst, m_mtr);
    init_index_entries();
    init_frag_entries();
    set_frag_node_page_no(FIL_NULL);
    set_index_page_no(FIL_NULL);
  }
 
  /** Get the amount of zlob data stored in this page. */
  ulint get_data_len() const {
    return (mach_read_from_4(frame() + OFFSET_DATA_LEN));
  }
 
  /** Get the page number. */
  page_no_t get_page_no() const { return (m_block->page.id.page_no()); }
 
  /** Get the page id of the first page of compressed LOB.
  @return page id of the first page of compressed LOB. */
  page_id_t get_page_id() const {
    ut_ad(m_block != nullptr);
 
    return (m_block->page.id);
  }
 
  fil_addr_t get_self_addr() const {
    page_no_t page_no = get_page_no();
    uint32_t offset = static_cast<uint32_t>(begin_data());
    return (fil_addr_t(page_no, offset));
  }
 
  /** All the index pages are singly linked with each other, and
  the first page contains the link to one index page.
  @param[in]  page_no  the page number of an index page. */
  void set_index_page_no(page_no_t page_no) {
    set_index_page_no(page_no, m_mtr);
  }
 
  /** All the index pages are singly linked with each other, and
  the first page contains the link to one index page.
  @param[in]  page_no  the page number of an index page.
  @param[in]  mtr      use this mini transaction context for redo logs. */
  void set_index_page_no(page_no_t page_no, mtr_t *mtr) {
    ut_ad(m_mtr != nullptr);
    mlog_write_ulint(frame() + OFFSET_INDEX_PAGE_NO, page_no, MLOG_4BYTES, mtr);
  }
 
  /** All the index pages are singly linked with each other, and
  the first page contains the link to one index page. Get that index
  page number.
  @return the index page number. */
  page_no_t get_index_page_no() const {
    return (mach_read_from_4(frame() + OFFSET_INDEX_PAGE_NO));
  }
 
  /** All the fragment pages are doubly linked with each other, and
  the first page contains the link to one fragment page in FIL_PAGE_PREV. Get
  that frag page number.
  @return the frag page number. */
  page_no_t get_frag_page_no() const { return (m_block->get_prev_page_no()); }
 
  /** All the fragment pages are doubly linked with each other, and
  the first page contains the link to one fragment page in FIL_PAGE_PREV. Get
  that frag page number.
  @param[in]   mtr   Mini-transaction to use for this read operation.
  @return the frag page number. */
  page_no_t get_frag_page_no(mtr_t *mtr) const {
    return (mtr_read_ulint(frame() + FIL_PAGE_PREV, MLOG_4BYTES, mtr));
  }
 
#ifdef UNIV_DEBUG
  /** Verify that the page number pointed to by FIL_PAGE_PREV of the first page
  of LOB is indeed a fragment page.  It uses its own mtr internally.
  @return true if it is a fragment page, false otherwise. */
  bool verify_frag_page_no();
#endif /* UNIV_DEBUG */
 
  /** All the fragment pages (@see z_frag_page_t) are doubly linked with each
  other, and the first page contains the link to one fragment page in
  FIL_PAGE_PREV.
  @param[in]  mtr      Mini-transaction for this modification.
  @param[in]  page_no  The page number of a fragment page. */
  void set_frag_page_no(mtr_t *mtr, page_no_t page_no) {
    ut_ad(verify_frag_page_no());
    set_prev_page_no(page_no, mtr);
  }
 
  /** All the fragment pages (@see z_frag_page_t) are doubly linked with each
  other, and the first page contains the link to one fragment page in
  FIL_PAGE_PREV.
  @param[in]  page_no  the page number of a fragment page. */
  void set_frag_page_no(page_no_t page_no) {
    ut_ad(verify_frag_page_no());
    set_prev_page_no(page_no, m_mtr);
  }
 
  /** All the frag node pages (@see z_frag_node_page_t) are singly linked with
  each other, and the first page contains the link to the last allocated frag
  node page. The last allocated FIL_PAGE_TYPE_ZLOB_FRAG_ENTRY  page will be the
  first in this list. This list is used to free these pages.
  @param[in]  page_no  the page number of an frag node page. */
  void set_frag_node_page_no(page_no_t page_no) {
    set_frag_node_page_no(page_no, m_mtr);
  }
 
  /** All the frag node pages (@see z_frag_node_page_t) are singly linked with
  each other, and the first page contains the link to the last allocated frag
  node page. The last allocated FIL_PAGE_TYPE_ZLOB_FRAG_ENTRY  page will be the
  first in this list. This list is used to free these pages.
  @param[in]  page_no  the page number of an frag node page.
  @param[in]  mtr      mini trx context to generate redo logs. */
  void set_frag_node_page_no(page_no_t page_no, mtr_t *mtr) {
    ut_ad(mtr != nullptr);
    mlog_write_ulint(frame() + OFFSET_FRAG_NODES_PAGE_NO, page_no, MLOG_4BYTES,
                     mtr);
  }
 
  /** Free all the z_frag_page_t pages. All the z_frag_page_t pages are
  singly linked to each other.  The head of the list is maintained in the
  first page.
  @return the number of pages freed. */
  size_t free_all_frag_node_pages();
 
  /** Free all the index pages.
  @return the number of pages freed. */
  size_t free_all_index_pages();
 
  /** Free all the fragment pages.
  @return the number of pages freed. */
  size_t free_all_frag_pages();
 
 private:
  /** Free all the fragment pages when the next page of the first LOB page IS
   NOT USED to link the fragment pages.
  @return the number of pages freed. */
  size_t free_all_frag_pages_old();
 
  /** Free all the fragment pages when the next page of the first LOB page IS
   USED to link the fragment pages.
  @return the number of pages freed. */
  size_t free_all_frag_pages_new();
 
 public:
  /** Free all the data pages.
  @return the number of pages freed. */
  size_t free_all_data_pages();
 
  /** All the frag node pages are singly linked with each other, and the
  first page contains the link to one frag node page. Get that frag node
  page number.
  @return the index page number. */
  page_no_t get_frag_node_page_no() {
    return (mach_read_from_4(frame() + OFFSET_FRAG_NODES_PAGE_NO));
  }
 
  /** Set the page type to FIL_PAGE_TYPE_UNKNOWN.  This is done while
  deallocating this page. */
  void set_page_type_unknown() {
    ut_ad(m_mtr != nullptr);
    mlog_write_ulint(frame() + FIL_PAGE_TYPE, FIL_PAGE_TYPE_UNKNOWN,
                     MLOG_2BYTES, m_mtr);
  }
 
  void set_page_type() {
    ut_ad(m_mtr != nullptr);
    mlog_write_ulint(frame() + FIL_PAGE_TYPE, FIL_PAGE_TYPE_ZLOB_FIRST,
                     MLOG_2BYTES, m_mtr);
  }
 
  void set_data_len(ulint len) {
    ut_ad(m_mtr != nullptr);
    mlog_write_ulint(frame() + OFFSET_DATA_LEN, len, MLOG_4BYTES, m_mtr);
  }
 
  /** Update the trx id in the header.
  @param[in]    tid     the given transaction identifier. */
  void set_trx_id(trx_id_t tid) {
    byte *ptr = frame() + OFFSET_TRX_ID;
    mach_write_to_6(ptr, tid);
    mlog_log_string(ptr, 6, m_mtr);
  }
 
  /** Update the trx id in the header, without generating redo
  log records.
  @param[in]    tid     the given transaction identifier. */
  void set_trx_id_no_redo(trx_id_t tid) {
    byte *ptr = frame() + OFFSET_TRX_ID;
    mach_write_to_6(ptr, tid);
  }
 
  /** Initialize the LOB version to 1. */
  void init_lob_version() {
    ut_ad(m_mtr != nullptr);
 
    mlog_write_ulint(frame() + OFFSET_LOB_VERSION, 1, MLOG_4BYTES, m_mtr);
  }
 
  /** Get the LOB version
  @return the LOB version. */
  uint32_t get_lob_version() {
    return (mach_read_from_4(frame() + OFFSET_LOB_VERSION));
  }
 
  /** Increment LOB version by 1. */
  uint32_t incr_lob_version();
 
  /** Get one byte of flags
  @return one byte of flags. */
  uint8_t get_flags() { return (mach_read_from_1(frame() + OFFSET_FLAGS)); }
 
  /** When the bit is set, the LOB is not partially updatable anymore.
  @return true, if partially updatable.
  @return false, if partially NOT updatable. */
  bool can_be_partially_updated() {
    uint8_t flags = get_flags();
    return (!(flags & 0x01));
  }
 
  /** When the bit is set, the LOB is not partially updatable anymore.
  Enable the bit.
  @param[in]    trx     the current transaction.*/
  void mark_cannot_be_partially_updated(trx_t *trx);
 
  void set_last_trx_id(trx_id_t tid) {
    byte *ptr = frame() + OFFSET_LAST_TRX_ID;
    mach_write_to_6(ptr, tid);
    mlog_log_string(ptr, 6, m_mtr);
  }
 
  /** Update the last transaction identifier in the header, without
  generating redo logs.
  @param[in]    tid     given transaction identifier.*/
  void set_last_trx_id_no_redo(trx_id_t tid) {
    byte *ptr = frame() + OFFSET_LAST_TRX_ID;
    mach_write_to_6(ptr, tid);
  }
 
  void set_last_trx_undo_no(undo_no_t undo_no) {
    ut_ad(m_mtr != nullptr);
 
    byte *ptr = frame() + OFFSET_LAST_UNDO_NO;
    mlog_write_ulint(ptr, undo_no, MLOG_4BYTES, m_mtr);
  }
 
  trx_id_t get_last_trx_id() const {
    byte *ptr = frame() + OFFSET_LAST_TRX_ID;
    return (mach_read_from_6(ptr));
  }
 
  undo_no_t get_last_trx_undo_no() const {
    byte *ptr = frame() + OFFSET_LAST_UNDO_NO;
    return (mach_read_from_4(ptr));
  }
 
  flst_base_node_t *free_list() const { return (frame() + OFFSET_FREE_LIST); }
 
  flst_base_node_t *index_list() const { return (frame() + OFFSET_INDEX_LIST); }
 
  flst_base_node_t *free_frag_list() const {
    return (frame() + OFFSET_FREE_FRAG_LIST);
  }
 
  flst_base_node_t *frag_list() const { return (frame() + OFFSET_FRAG_LIST); }
 
  void init_frag_entries() {
    flst_base_node_t *free_frag_lst = free_frag_list();
    ulint n = get_n_frag_entries();
    for (ulint i = 0; i < n; ++i) {
      flst_node_t *ptr = frame() + begin_frag_entries();
      ptr += (i * z_frag_entry_t::SIZE);
      z_frag_entry_t frag_entry(ptr, m_mtr);
      frag_entry.init();
      frag_entry.push_back(free_frag_lst);
    }
  }
 
  void init_index_entries();
 
  /** Allocate a fragment of the given size.  This involves finding a
  fragment page, that has space to store len bytes of data. If necessary,
  allocate a new fragment page.
  @param[in]    bulk            true if it is bulk operation
                                  (OPCODE_INSERT_BULK), false otherwise.
  @param[in]    len             length of data to be stored in
                                  fragment page.
  @param[out]   frag_page       the fragment page with the needed
                                  free space.
  @param[out]   entry           fragment page entry representing frag_page.
  @return fragment identifier within the fragment page.
  @return FRAG_ID_NULL if fragment could not be allocated. */
  frag_id_t alloc_fragment(bool bulk, ulint len, z_frag_page_t &frag_page,
                           z_frag_entry_t &entry);
 
  /** Allocate one index entry.  If there is no free index entry,
  allocate an index page (a page full of z_index_entry_t objects)
  and service the request.
  @return the allocated index entry. */
  z_index_entry_t alloc_index_entry(bool bulk);
 
  /** Allocate one frag page entry.  If there is no free frag
  entry, allocate an frag node page (a page full of z_frag_entry_t
  objects) and service the request.
  @return the allocated frag entry. */
  z_frag_entry_t alloc_frag_entry(bool bulk);
 
  /** Print the index entries. */
  std::ostream &print_index_entries(std::ostream &out) const;
 
  /** Print the index entries. */
  std::ostream &print_frag_entries(std::ostream &out) const;
 
  /** Print the page. */
  std::ostream &print(std::ostream &out) const;
 
  byte *frame() const { return (buf_block_get_frame(m_block)); }
 
  /** Load the page, in x-latch mode, containing the given file address.
  @param[in]    addr    given file address
  @return       the file list node pointer. */
  flst_node_t *addr2ptr_x(fil_addr_t &addr) const {
    return (addr2ptr_x(addr, m_mtr));
  }
 
  /** Load the page, in x-latch mode, containing the given file address.
  @param[in]    addr    given file address
  @param[in]    mtr     the mini-transaction context to be used.
  @return       the file list node pointer. */
  flst_node_t *addr2ptr_x(fil_addr_t &addr, mtr_t *mtr) const {
    space_id_t space = dict_index_get_space(m_index);
    const page_size_t page_size = dict_table_page_size(m_index->table);
    return (fut_get_ptr(space, page_size, addr, RW_X_LATCH, mtr));
  }
 
  /** Load the page, in s-latch mode, containing the given file address.
  @param[in]    addr    given file address
  @return       the file list node pointer. */
  flst_node_t *addr2ptr_s(fil_addr_t &addr) {
    space_id_t space = dict_index_get_space(m_index);
    const page_size_t page_size = dict_table_page_size(m_index->table);
    return (fut_get_ptr(space, page_size, addr, RW_S_LATCH, m_mtr));
  }
 
  /** Load the entry available in the given file address.
  @param[in]    addr    file address
  @param[out]   entry   the entry to be loaded.*/
  void load_entry_s(fil_addr_t &addr, z_index_entry_t &entry);
 
  /** Load the entry available in the given file address.
  @param[in]    addr    file address
  @param[out]   entry   the entry to be loaded.*/
  void load_entry_x(fil_addr_t &addr, z_index_entry_t &entry);
 
  /** Free all the pages of the zlob.
  @return the total number of pages freed. */
  size_t destroy();
 
  /** Free all the pages of the zlob except the first page.
  @return the total number of pages freed. */
  size_t make_empty();
 
#ifdef UNIV_DEBUG
 private:
  /** Validate the LOB.  This is a costly function.  We need to avoid using
  this directly, instead call z_first_page_t::validate().
  @return true if valid, false otherwise. */
  bool validate_low();
 
 public:
  /** Validate the LOB.
  @return true if valid, false otherwise. */
  bool validate() {
    static const uint32_t FREQ = 50;
    static std::atomic<uint32_t> n{0};
 
    bool valid = true;
    if (++n % FREQ == 0) {
      valid = validate_low();
    }
    return (valid);
  }
#endif /* UNIV_DEBUG */
 
  /** Get the buffer block of the first page of LOB.
  @return the buffer block of the first page of LOB. */
  buf_block_t *get_block() const { return (m_block); }
 
 public:
  void set_mtr(mtr_t *mtr) { m_mtr = mtr; }
 
  /** Restart the given mtr. The first page must already be x-latched by the
  m_mtr.
  @param[in]   mtr   the mini-transaction context which is to be restarted. */
  void restart_mtr(mtr_t *mtr) {
    ut_ad(mtr != m_mtr);
 
    mtr_commit(mtr);
    mtr_start(mtr);
    mtr->set_log_mode(m_mtr->get_log_mode());
    load_x(mtr);
  }
 
 private:
  /** The buffer block of the first page. */
  buf_block_t *m_block;
 
  /** The mini-transaction context. */
  mtr_t *m_mtr;
 
  /** The index dictionary object. */
  dict_index_t *m_index;
 
};  // struct z_first_page_t
 
/** Overloading the global output parameter to print object of type
z_first_page_t into the given output stream.
@param[in,out]          out     output stream.
@param[in]              obj     object to be printed.
@return the output stream. */
inline std::ostream &operator<<(std::ostream &out, const z_first_page_t &obj) {
  return (obj.print(out));
}
 
} /* namespace lob */
 
#endif /* zlob0first_h */