Database Internals

+----------+------------------------------------------------------+-------+
| table_id | name                                                 | space |
+----------+------------------------------------------------------+-------+
|     3282 | silver/t1                                            |  2114 |
|     3283 | silver/fts_0000000000000cd2_being_deleted            |  2115 |
|     3284 | silver/fts_0000000000000cd2_being_deleted_cache      |  2116 |
|     3285 | silver/fts_0000000000000cd2_config                   |  2117 |
|     3286 | silver/fts_0000000000000cd2_deleted                  |  2118 |
|     3287 | silver/fts_0000000000000cd2_deleted_cache            |  2119 |
|     3288 | silver/fts_0000000000000cd2_0000000000000ff1_index_1 |  2120 |
|     3289 | silver/fts_0000000000000cd2_0000000000000ff1_index_2 |  2121 |
|     3290 | silver/fts_0000000000000cd2_0000000000000ff1_index_3 |  2122 |
|     3291 | silver/fts_0000000000000cd2_0000000000000ff1_index_4 |  2123 |
|     3292 | silver/fts_0000000000000cd2_0000000000000ff1_index_5 |  2124 |
|     3293 | silver/fts_0000000000000cd2_0000000000000ff1_index_6 |  2125 |
+----------+------------------------------------------------------+-------+

mysql> SELECT * FROM information_schema.innodb_ft_index_cache;
+----------+--------------+-------------+-----------+--------+----------+
| WORD     | FIRST_DOC_ID | LAST_DOC_ID | DOC_COUNT | DOC_ID | POSITION |
+----------+--------------+-------------+-----------+--------+----------+
| database |            7 |           7 |         1 |      7 |        7 |
| oracle   |            7 |           7 |         1 |      7 |        0 |
+----------+--------------+-------------+-----------+--------+----------+

mysql> SELECT * FROM information_schema.innodb_ft_index_table; 
+------------+--------------+-------------+-----------+--------+----------+
| WORD       | FIRST_DOC_ID | LAST_DOC_ID | DOC_COUNT | DOC_ID | POSITION |
+------------+--------------+-------------+-----------+--------+----------+
| aurora     |            2 |           4 |         2 |      2 |        0 |
| aurora     |            2 |           4 |         2 |      4 |        0 |
| community  |            3 |           3 |         1 |      3 |        6 |
| database   |            2 |           5 |         4 |      2 |       13 |
| database   |            2 |           5 |         4 |      3 |       16 |
| database   |            2 |           5 |         4 |      4 |       18 |
| database   |            2 |           5 |         4 |      5 |        8 |
| mongodb    |            5 |           5 |         1 |      5 |        0 |
| mysql      |            2 |           3 |         2 |      2 |        7 |
| mysql      |            2 |           3 |         2 |      3 |        0 |
| postgresql |            4 |           4 |         1 |      4 |        7 |
+------------+--------------+-------------+-----------+--------+----------+

mysql> SELECT * FROM information_schema.innodb_ft_deleted;
+--------+
| DOC_ID |
+--------+
|      4 |
+--------+

int ha_innobase::ft_read(uchar *buf) /*!< in/out: buf contain result row */
{
...
...
    search_doc_id = ranking->doc_id;

    /* We pass a pointer of search_doc_id because it will be
    converted to storage byte order used in the search
    tuple. */
    innobase_fts_create_doc_id_key(tuple, index, &search_doc_id);

    auto ret = innobase_srv_conc_enter_innodb(m_prebuilt);

    if (ret == DB_SUCCESS) {
      ret = row_search_for_mysql((byte *)buf, PAGE_CUR_GE, m_prebuilt,
                                 ROW_SEL_EXACT, 0);
      innobase_srv_conc_exit_innodb(m_prebuilt);
    }

mysql> SELECT * FROM information_schema.innodb_ft_index_cache WHERE word = 'oracle';
+----------+--------------+-------------+-----------+--------+----------+
| WORD     | FIRST_DOC_ID | LAST_DOC_ID | DOC_COUNT | DOC_ID | POSITION |
+----------+--------------+-------------+-----------+--------+----------+
| database |            7 |           7 |         1 |      7 |        7 |
+----------+--------------+-------------+-----------+--------+----------+

Process 4586 stopped
* thread #42, name = 'connection', stop reason = step over
    frame #0: 0x000000010249d604 mysqld`ha_innobase::ft_read(this=0x00000001310d6830, buf="\U00000002\U00000003") at ha_innodb.cc:11492:21
   11489
   11490	    fts_ranking_t *ranking = rbt_value(fts_ranking_t, result->current);
   11491
-> 11492	    search_doc_id = ranking->doc_id;
   11493
   11494	    /* We pass a pointer of search_doc_id because it will be
   11495	    converted to storage byte order used in the search
(lldb) p ranking->doc_id
(doc_id_t) 7

static inline dberr_t row_search_for_mysql(byte *buf, page_cur_mode_t mode,
                                           row_prebuilt_t *prebuilt,
                                           ulint match_mode, ulint direction) {
  if (!prebuilt->table->is_intrinsic()) {
    return (row_search_mvcc(buf, mode, prebuilt, match_mode, direction));
  } else {
    return (row_search_no_mvcc(buf, mode, prebuilt, match_mode, direction));
  }
}

dberr_t row_search_mvcc(byte *buf, page_cur_mode_t mode,
                        row_prebuilt_t *prebuilt, ulint match_mode,
                        const ulint direction) {
...
...
    if (!srv_read_only_mode) {
      trx_assign_read_view(trx);
    }
...
...

ReadView *trx_assign_read_view(trx_t *trx) /*!< in/out: active transaction */
{
  ut_ad(trx_can_be_handled_by_current_thread_or_is_hp_victim(trx));
  ut_ad(trx->state.load(std::memory_order_relaxed) == TRX_STATE_ACTIVE);

  if (srv_read_only_mode) {
    ut_ad(trx->read_view == nullptr);
    return (nullptr);

  } else if (!MVCC::is_view_active(trx->read_view)) {
    trx_sys->mvcc->view_open(trx->read_view, trx);
  }

  return (trx->read_view);
}

(ReadView) {
	  m_low_limit_id = 1696644
	  m_up_limit_id = 1696644
	  m_creator_trx_id = 0
	  m_ids = {
	    m_ptr = 0x0000000000000000
	    m_size = 0
	    m_reserved = 0
	  }
	  m_low_limit_no = 1696628
	  m_view_low_limit_no = 1696628
	  m_closed = false
	  pad1 = ""
	  m_view_list = {
	    prev = nullptr
	    next = nullptr
	  }
	}

expr trx->read_view->m_low_limit_id = 1696645 // (1696644 + 1)
expr trx->read_view->m_up_limit_id = 1696645 // (1696644 + 1)
expr trx->read_view->m_low_limit_no = 1696629 // (1696628 + 1)
expr trx->read_view->m_view_low_limit_no = 1696729 // (1696728 + 1)

# m_low_limit_id를 증가시키면 레코드를 읽을 수 있다.
SELECT * FROM t1 WHERE MATCH(title) AGAINST ('oracle' IN NATURAL LANGUAGE MODE);
+----+-----------------+---------+
| id | title           | content |
+----+-----------------+---------+
|  3 | Oracle Database | NULL    |
+----+-----------------+---------+

1) ref_row_iterators.cc
	int FullTextSearchIterator::Read()
		2) handler.cc
			result = ft_read(buf);
				3) ha_innodb.cc
                    ha_innobase::ft_read()
					fts_ranking_t *ranking = rbt_value(fts_ranking_t, result->current);
					# 전문 검색 인덱스 정보가 담긴 구조체와 함께 row_search_for_mysql() 함수를 호출한다.
					row_search_for_mysql((byte *)buf, PAGE_CUR_GE, m_prebuilt, ROW_SEL_EXACT, 0);
						4) row0sel.ic
							# t1 테이블이 내부적으로 사용되는 테이블인지 임시 테이블인지를 판단하여 row_search_mvcc() 함수 호출
							row_search_for_mysql()
								row_search_mvcc(buf, mode, prebuilt, match_mode, direction)
									5) row0sel.cc
										# SELECT문의 잠금 유형(LOCK_TYPE)이 LOCK_NONE이면 ReadView 생성
										trx_assign_read_view()
											6) trx0trx.cc
											  # ReadView 반환
												p *trx->read_view
													(ReadView) {
													  m_low_limit_id = 1696644
													  m_up_limit_id = 1696644
													  m_creator_trx_id = 0
													  m_ids = {
													    m_ptr = 0x0000000000000000
													    m_size = 0
													    m_reserved = 0
													  }
													  m_low_limit_no = 1696628
													  m_view_low_limit_no = 1696628
													  m_closed = false
													  pad1 = ""
													  m_view_list = {
													    prev = nullptr
													    next = nullptr
													  }
													}
									5) row0sel.cc
					  4) row0sel.ic
				3) ha_innodb.cc
						case DB_RECORD_NOT_FOUND:
							...
							error = HA_ERR_END_OF_FILE;
						default:
							break;
					return (HA_ERR_END_OF_FILE);