mariadb/storage/innobase/row/row0ftsort.cc

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

Copyright (c) 2010, 2016, Oracle and/or its affiliates. All Rights Reserved.
Copyright (c) 2015, 2018, MariaDB Corporation.

This program is free software; you can redistribute it and/or modify it under
the terms of the GNU General Public License as published by the Free Software
Foundation; version 2 of the License.

This program is distributed in the hope that it will be useful, but WITHOUT
ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or FITNESS
FOR A PARTICULAR PURPOSE. See the GNU General Public License for more details.

You should have received a copy of the GNU General Public License along with
this program; if not, write to the Free Software Foundation, Inc.,
51 Franklin Street, Suite 500, Boston, MA 02110-1335 USA

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

/**************************************************//**
@file row/row0ftsort.cc
Create Full Text Index with (parallel) merge sort

Created 10/13/2010 Jimmy Yang
*******************************************************/

#include "row0ftsort.h"
#include "dict0dict.h"
#include "row0merge.h"
#include "row0row.h"
#include "btr0cur.h"
#include "fts0plugin.h"
#include "log0crypt.h"

/** Read the next record to buffer N.
@param N index into array of merge info structure */
#define ROW_MERGE_READ_GET_NEXT(N)					\
	do {								\
		b[N] = row_merge_read_rec(				\
			block[N], buf[N], b[N], index,			\
			fd[N], &foffs[N], &mrec[N], offsets[N],		\
			crypt_block[N], space);				\
		if (UNIV_UNLIKELY(!b[N])) {				\
			if (mrec[N]) {					\
				goto exit;				\
			}						\
		}							\
	} while (0)

/** Parallel sort degree */
ulong	fts_sort_pll_degree	= 2;

/*********************************************************************//**
Create a temporary "fts sort index" used to merge sort the
tokenized doc string. The index has three "fields":

1) Tokenized word,
2) Doc ID (depend on number of records to sort, it can be a 4 bytes or 8 bytes
integer value)
3) Word's position in original doc.

@see fts_create_one_index_table()

@return dict_index_t structure for the fts sort index */
dict_index_t*
row_merge_create_fts_sort_index(
/*============================*/
	dict_index_t*		index,	/*!< in: Original FTS index
					based on which this sort index
					is created */
	const dict_table_t*	table,	/*!< in: table that FTS index
					is being created on */
	ibool*			opt_doc_id_size)
					/*!< out: whether to use 4 bytes
					instead of 8 bytes integer to
					store Doc ID during sort */
{
	dict_index_t*   new_index;
	dict_field_t*   field;
	dict_field_t*   idx_field;
	CHARSET_INFO*	charset;

	// FIXME: This name shouldn't be hard coded here.
	new_index = dict_mem_index_create(
		index->table->name.m_name, "tmp_fts_idx", 0, DICT_FTS, 3);

	new_index->id = index->id;
	new_index->table = (dict_table_t*) table;
	new_index->n_uniq = FTS_NUM_FIELDS_SORT;
	new_index->n_def = FTS_NUM_FIELDS_SORT;
	new_index->cached = TRUE;
	new_index->parser = index->parser;

	idx_field = dict_index_get_nth_field(index, 0);
	charset = fts_index_get_charset(index);

	/* The first field is on the Tokenized Word */
	field = dict_index_get_nth_field(new_index, 0);
	field->name = NULL;
	field->prefix_len = 0;
	field->col = static_cast<dict_col_t*>(
		mem_heap_alloc(new_index->heap, sizeof(dict_col_t)));
	field->col->prtype = idx_field->col->prtype | DATA_NOT_NULL;
	field->col->mtype = charset == &my_charset_latin1
		? DATA_VARCHAR : DATA_VARMYSQL;
	field->col->mbminlen = idx_field->col->mbminlen;
	field->col->mbmaxlen = idx_field->col->mbmaxlen;
	field->col->len = HA_FT_MAXCHARLEN * field->col->mbmaxlen;

	field->fixed_len = 0;

	/* Doc ID */
	field = dict_index_get_nth_field(new_index, 1);
	field->name = NULL;
	field->prefix_len = 0;
	field->col = static_cast<dict_col_t*>(
		mem_heap_alloc(new_index->heap, sizeof(dict_col_t)));
	field->col->mtype = DATA_INT;
	*opt_doc_id_size = FALSE;

	/* Check whether we can use 4 bytes instead of 8 bytes integer
	field to hold the Doc ID, thus reduce the overall sort size */
	if (DICT_TF2_FLAG_IS_SET(table, DICT_TF2_FTS_ADD_DOC_ID)) {
		/* If Doc ID column is being added by this create
		index, then just check the number of rows in the table */
		if (dict_table_get_n_rows(table) < MAX_DOC_ID_OPT_VAL) {
			*opt_doc_id_size = TRUE;
		}
	} else {
		doc_id_t	max_doc_id;

		/* If the Doc ID column is supplied by user, then
		check the maximum Doc ID in the table */
		max_doc_id = fts_get_max_doc_id((dict_table_t*) table);

		if (max_doc_id && max_doc_id < MAX_DOC_ID_OPT_VAL) {
			*opt_doc_id_size = TRUE;
		}
	}

	if (*opt_doc_id_size) {
		field->col->len = sizeof(ib_uint32_t);
		field->fixed_len = sizeof(ib_uint32_t);
	} else {
		field->col->len = FTS_DOC_ID_LEN;
		field->fixed_len = FTS_DOC_ID_LEN;
	}

	field->col->prtype = DATA_NOT_NULL | DATA_BINARY_TYPE;

	field->col->mbminlen = 0;
	field->col->mbmaxlen = 0;

	/* The third field is on the word's position in the original doc */
	field = dict_index_get_nth_field(new_index, 2);
	field->name = NULL;
	field->prefix_len = 0;
	field->col = static_cast<dict_col_t*>(
		mem_heap_alloc(new_index->heap, sizeof(dict_col_t)));
	field->col->mtype = DATA_INT;
	field->col->len = 4 ;
	field->fixed_len = 4;
	field->col->prtype = DATA_NOT_NULL;
	field->col->mbminlen = 0;
	field->col->mbmaxlen = 0;

	return(new_index);
}
/*********************************************************************//**
Initialize FTS parallel sort structures.
@return TRUE if all successful */
ibool
row_fts_psort_info_init(
/*====================*/
	trx_t*			trx,	/*!< in: transaction */
	row_merge_dup_t*	dup,	/*!< in,own: descriptor of
					FTS index being created */
	const dict_table_t*	new_table,/*!< in: table on which indexes are
					created */
	ibool			opt_doc_id_size,
					/*!< in: whether to use 4 bytes
					instead of 8 bytes integer to
					store Doc ID during sort */
	fts_psort_t**		psort,	/*!< out: parallel sort info to be
					instantiated */
	fts_psort_t**		merge)	/*!< out: parallel merge info
					to be instantiated */
{
	ulint			i;
	ulint			j;
	fts_psort_common_t*	common_info = NULL;
	fts_psort_t*		psort_info = NULL;
	fts_psort_t*		merge_info = NULL;
	ulint			block_size;
	ibool			ret = TRUE;
	bool			encrypted = false;

	block_size = 3 * srv_sort_buf_size;

	*psort = psort_info = static_cast<fts_psort_t*>(ut_zalloc_nokey(
		 fts_sort_pll_degree * sizeof *psort_info));

	if (!psort_info) {
		ut_free(dup);
		return(FALSE);
	}

	/* Common Info for all sort threads */
	common_info = static_cast<fts_psort_common_t*>(
		ut_malloc_nokey(sizeof *common_info));

	if (!common_info) {
		ut_free(dup);
		ut_free(psort_info);
		return(FALSE);
	}

	common_info->dup = dup;
	common_info->new_table = (dict_table_t*) new_table;
	common_info->trx = trx;
	common_info->all_info = psort_info;
	common_info->sort_event = os_event_create(0);
	common_info->merge_event = os_event_create(0);
	common_info->opt_doc_id_size = opt_doc_id_size;

	if (log_tmp_is_encrypted()) {
		encrypted = true;
	}

	ut_ad(trx->mysql_thd != NULL);
	const char*	path = thd_innodb_tmpdir(trx->mysql_thd);
	/* There will be FTS_NUM_AUX_INDEX number of "sort buckets" for
	each parallel sort thread. Each "sort bucket" holds records for
	a particular "FTS index partition" */
	for (j = 0; j < fts_sort_pll_degree; j++) {

		UT_LIST_INIT(
			psort_info[j].fts_doc_list, &fts_doc_item_t::doc_list);

		for (i = 0; i < FTS_NUM_AUX_INDEX; i++) {

			psort_info[j].merge_file[i] =
				 static_cast<merge_file_t*>(
					ut_zalloc_nokey(sizeof(merge_file_t)));

			if (!psort_info[j].merge_file[i]) {
				ret = FALSE;
				goto func_exit;
			}

			psort_info[j].merge_buf[i] = row_merge_buf_create(
				dup->index);

			if (row_merge_file_create(psort_info[j].merge_file[i],
						  path) < 0) {
				goto func_exit;
			}

			/* Need to align memory for O_DIRECT write */
			psort_info[j].block_alloc[i] =
				static_cast<row_merge_block_t*>(ut_malloc_nokey(
					block_size + 1024));

			psort_info[j].merge_block[i] =
				static_cast<row_merge_block_t*>(
					ut_align(
					psort_info[j].block_alloc[i], 1024));

			if (!psort_info[j].merge_block[i]) {
				ret = FALSE;
				goto func_exit;
			}

			/* If tablespace is encrypted, allocate additional buffer for
			encryption/decryption. */
			if (encrypted) {

				/* Need to align memory for O_DIRECT write */
				psort_info[j].crypt_alloc[i] =
					static_cast<row_merge_block_t*>(ut_malloc_nokey(
							block_size + 1024));

				psort_info[j].crypt_block[i] =
					static_cast<row_merge_block_t*>(
						ut_align(
							psort_info[j].crypt_alloc[i], 1024));

				if (!psort_info[j].crypt_block[i]) {
					ret = FALSE;
					goto func_exit;
				}
			} else {
				psort_info[j].crypt_alloc[i] = NULL;
				psort_info[j].crypt_block[i] = NULL;
			}
		}

		psort_info[j].child_status = 0;
		psort_info[j].state = 0;
		psort_info[j].psort_common = common_info;
		psort_info[j].error = DB_SUCCESS;
		psort_info[j].memory_used = 0;
		mutex_create(LATCH_ID_FTS_PLL_TOKENIZE, &psort_info[j].mutex);
	}

	/* Initialize merge_info structures parallel merge and insert
	into auxiliary FTS tables (FTS_INDEX_TABLE) */
	*merge = merge_info = static_cast<fts_psort_t*>(
		ut_malloc_nokey(FTS_NUM_AUX_INDEX * sizeof *merge_info));

	for (j = 0; j < FTS_NUM_AUX_INDEX; j++) {

		merge_info[j].child_status = 0;
		merge_info[j].state = 0;
		merge_info[j].psort_common = common_info;
	}

func_exit:
	if (!ret) {
		row_fts_psort_info_destroy(psort_info, merge_info);
	}

	return(ret);
}
/*********************************************************************//**
Clean up and deallocate FTS parallel sort structures, and close the
merge sort files  */
void
row_fts_psort_info_destroy(
/*=======================*/
	fts_psort_t*	psort_info,	/*!< parallel sort info */
	fts_psort_t*	merge_info)	/*!< parallel merge info */
{
	ulint	i;
	ulint	j;

	if (psort_info) {
		for (j = 0; j < fts_sort_pll_degree; j++) {
			for (i = 0; i < FTS_NUM_AUX_INDEX; i++) {
				if (psort_info[j].merge_file[i]) {
					row_merge_file_destroy(
						psort_info[j].merge_file[i]);
				}

				ut_free(psort_info[j].block_alloc[i]);
				ut_free(psort_info[j].merge_file[i]);

				if (psort_info[j].crypt_alloc[i]) {
					ut_free(psort_info[j].crypt_alloc[i]);
				}
			}

			mutex_free(&psort_info[j].mutex);
		}

		os_event_destroy(merge_info[0].psort_common->sort_event);
		os_event_destroy(merge_info[0].psort_common->merge_event);
		ut_free(merge_info[0].psort_common->dup);
		ut_free(merge_info[0].psort_common);
		ut_free(psort_info);
	}

	ut_free(merge_info);
}
/*********************************************************************//**
Free up merge buffers when merge sort is done */
void
row_fts_free_pll_merge_buf(
/*=======================*/
	fts_psort_t*	psort_info)	/*!< in: parallel sort info */
{
	ulint	j;
	ulint	i;

	if (!psort_info) {
		return;
	}

	for (j = 0; j < fts_sort_pll_degree; j++) {
		for (i = 0; i < FTS_NUM_AUX_INDEX; i++) {
			row_merge_buf_free(psort_info[j].merge_buf[i]);
		}
	}

	return;
}

/*********************************************************************//**
FTS plugin parser 'myql_add_word' callback function for row merge.
Refer to 'st_mysql_ftparser_param' for more detail.
@return always returns 0 */
static
int
row_merge_fts_doc_add_word_for_parser(
/*==================================*/
	MYSQL_FTPARSER_PARAM	*param,		/* in: parser paramter */
	const char		*word,		/* in: token word */
	int			word_len,	/* in: word len */
	MYSQL_FTPARSER_BOOLEAN_INFO*	boolean_info)	/* in: boolean info */
{
	fts_string_t		str;
	fts_tokenize_ctx_t*	t_ctx;
	row_fts_token_t*	fts_token;
	byte*			ptr;

	ut_ad(param);
	ut_ad(param->mysql_ftparam);
	ut_ad(word);
	ut_ad(boolean_info);

	t_ctx = static_cast<fts_tokenize_ctx_t*>(param->mysql_ftparam);
	ut_ad(t_ctx);

	str.f_str = (byte*)(word);
	str.f_len = word_len;
	str.f_n_char = fts_get_token_size(
		(CHARSET_INFO*)param->cs, word, word_len);

	/* JAN: TODO: MySQL 5.7 FTS
	ut_ad(boolean_info->position >= 0);
	*/

	ptr = static_cast<byte*>(ut_malloc_nokey(sizeof(row_fts_token_t)
			+ sizeof(fts_string_t) + str.f_len));
	fts_token = reinterpret_cast<row_fts_token_t*>(ptr);
	fts_token->text = reinterpret_cast<fts_string_t*>(
			ptr + sizeof(row_fts_token_t));
	fts_token->text->f_str = static_cast<byte*>(
			ptr + sizeof(row_fts_token_t) + sizeof(fts_string_t));

	fts_token->text->f_len = str.f_len;
	fts_token->text->f_n_char = str.f_n_char;
	memcpy(fts_token->text->f_str, str.f_str, str.f_len);

	/* JAN: TODO: MySQL 5.7 FTS
	fts_token->position = boolean_info->position;
	*/

	/* Add token to list */
	UT_LIST_ADD_LAST(t_ctx->fts_token_list, fts_token);

	return(0);
}

/*********************************************************************//**
Tokenize by fts plugin parser */
static
void
row_merge_fts_doc_tokenize_by_parser(
/*=================================*/
	fts_doc_t*		doc,	/* in: doc to tokenize */
	st_mysql_ftparser*	parser,	/* in: plugin parser instance */
	fts_tokenize_ctx_t*	t_ctx)	/* in/out: tokenize ctx instance */
{
	MYSQL_FTPARSER_PARAM	param;

	ut_a(parser);

	/* Set paramters for param */
	param.mysql_parse = fts_tokenize_document_internal;
	param.mysql_add_word = row_merge_fts_doc_add_word_for_parser;
	param.mysql_ftparam = t_ctx;
	param.cs = doc->charset;
	param.doc = reinterpret_cast<char*>(doc->text.f_str);
	param.length = static_cast<int>(doc->text.f_len);
	param.mode= MYSQL_FTPARSER_SIMPLE_MODE;

	PARSER_INIT(parser, &param);
	/* We assume parse returns successfully here. */
	parser->parse(&param);
	PARSER_DEINIT(parser, &param);
}

/*********************************************************************//**
Tokenize incoming text data and add to the sort buffer.
@see row_merge_buf_encode()
@return	TRUE if the record passed, FALSE if out of space */
static
ibool
row_merge_fts_doc_tokenize(
/*=======================*/
	row_merge_buf_t**	sort_buf,	/*!< in/out: sort buffer */
	doc_id_t		doc_id,		/*!< in: Doc ID */
	fts_doc_t*		doc,		/*!< in: Doc to be tokenized */
	merge_file_t**		merge_file,	/*!< in/out: merge file */
	ibool			opt_doc_id_size,/*!< in: whether to use 4 bytes
						instead of 8 bytes integer to
						store Doc ID during sort*/
	fts_tokenize_ctx_t*	t_ctx)          /*!< in/out: tokenize context */
{
	ulint		inc = 0;
	fts_string_t	str;
	ulint		len;
	row_merge_buf_t* buf;
	dfield_t*	field;
	fts_string_t	t_str;
	ibool		buf_full = FALSE;
	byte		str_buf[FTS_MAX_WORD_LEN + 1];
	ulint		data_size[FTS_NUM_AUX_INDEX];
	ulint		n_tuple[FTS_NUM_AUX_INDEX];
	st_mysql_ftparser*	parser;

	t_str.f_n_char = 0;
	t_ctx->buf_used = 0;

	memset(n_tuple, 0, FTS_NUM_AUX_INDEX * sizeof(ulint));
	memset(data_size, 0, FTS_NUM_AUX_INDEX * sizeof(ulint));

	parser = sort_buf[0]->index->parser;

	/* Tokenize the data and add each word string, its corresponding
	doc id and position to sort buffer */
	while (t_ctx->processed_len < doc->text.f_len) {
		ulint		idx = 0;
		ulint		cur_len;
		doc_id_t	write_doc_id;
		row_fts_token_t* fts_token = NULL;

		if (parser != NULL) {
			if (t_ctx->processed_len == 0) {
				UT_LIST_INIT(t_ctx->fts_token_list, &row_fts_token_t::token_list);

				/* Parse the whole doc and cache tokens */
				row_merge_fts_doc_tokenize_by_parser(doc,
					parser, t_ctx);

				/* Just indictate we have parsed all the word */
				t_ctx->processed_len += 1;
			}

			/* Then get a token */
			fts_token = UT_LIST_GET_FIRST(t_ctx->fts_token_list);
			if (fts_token) {
				str.f_len = fts_token->text->f_len;
				str.f_n_char = fts_token->text->f_n_char;
				str.f_str = fts_token->text->f_str;
			} else {
				ut_ad(UT_LIST_GET_LEN(t_ctx->fts_token_list) == 0);
				/* Reach the end of the list */
				t_ctx->processed_len = doc->text.f_len;
				break;
			}
		} else {
			inc = innobase_mysql_fts_get_token(
				doc->charset,
				doc->text.f_str + t_ctx->processed_len,
				doc->text.f_str + doc->text.f_len, &str);

			ut_a(inc > 0);
		}

		/* Ignore string whose character number is less than
		"fts_min_token_size" or more than "fts_max_token_size" */
		if (!fts_check_token(&str, NULL, NULL)) {
			if (parser != NULL) {
				UT_LIST_REMOVE(t_ctx->fts_token_list, fts_token);
				ut_free(fts_token);
			} else {
				t_ctx->processed_len += inc;
			}

			continue;
		}

		t_str.f_len = innobase_fts_casedn_str(
			doc->charset, (char*) str.f_str, str.f_len,
			(char*) &str_buf, FTS_MAX_WORD_LEN + 1);

		t_str.f_str = (byte*) &str_buf;

		/* if "cached_stopword" is defined, ignore words in the
		stopword list */
		if (!fts_check_token(&str, t_ctx->cached_stopword,
				     doc->charset)) {
			if (parser != NULL) {
				UT_LIST_REMOVE(t_ctx->fts_token_list, fts_token);
				ut_free(fts_token);
			} else {
				t_ctx->processed_len += inc;
			}

			continue;
		}

		/* There are FTS_NUM_AUX_INDEX auxiliary tables, find
		out which sort buffer to put this word record in */
		t_ctx->buf_used = fts_select_index(
			doc->charset, t_str.f_str, t_str.f_len);

		buf = sort_buf[t_ctx->buf_used];

		ut_a(t_ctx->buf_used < FTS_NUM_AUX_INDEX);
		idx = t_ctx->buf_used;

		mtuple_t* mtuple = &buf->tuples[buf->n_tuples + n_tuple[idx]];

		field = mtuple->fields = static_cast<dfield_t*>(
			mem_heap_alloc(buf->heap,
				       FTS_NUM_FIELDS_SORT * sizeof *field));

		/* The first field is the tokenized word */
		dfield_set_data(field, t_str.f_str, t_str.f_len);
		len = dfield_get_len(field);

		dict_col_copy_type(dict_index_get_nth_col(buf->index, 0), &field->type);
		field->type.prtype |= DATA_NOT_NULL;
		ut_ad(len <= field->type.len);

		/* For the temporary file, row_merge_buf_encode() uses
		1 byte for representing the number of extra_size bytes.
		This number will always be 1, because for this 3-field index
		consisting of one variable-size column, extra_size will always
		be 1 or 2, which can be encoded in one byte.

		The extra_size is 1 byte if the length of the
		variable-length column is less than 128 bytes or the
		maximum length is less than 256 bytes. */

		/* One variable length column, word with its lenght less than
		fts_max_token_size, add one extra size and one extra byte.

		Since the max length for FTS token now is larger than 255,
		so we will need to signify length byte itself, so only 1 to 128
		bytes can be used for 1 bytes, larger than that 2 bytes. */
		if (len < 128 || field->type.len < 256) {
			/* Extra size is one byte. */
			cur_len = 2 + len;
		} else {
			/* Extra size is two bytes. */
			cur_len = 3 + len;
		}

		dfield_dup(field, buf->heap);
		field++;

		/* The second field is the Doc ID */

		ib_uint32_t	doc_id_32_bit;

		if (!opt_doc_id_size) {
			fts_write_doc_id((byte*) &write_doc_id, doc_id);

			dfield_set_data(
				field, &write_doc_id, sizeof(write_doc_id));
		} else {
			mach_write_to_4(
				(byte*) &doc_id_32_bit, (ib_uint32_t) doc_id);

			dfield_set_data(
				field, &doc_id_32_bit, sizeof(doc_id_32_bit));
		}

		len = field->len;
		ut_ad(len == FTS_DOC_ID_LEN || len == sizeof(ib_uint32_t));

		field->type.mtype = DATA_INT;
		field->type.prtype = DATA_NOT_NULL | DATA_BINARY_TYPE;
		field->type.len = len;
		field->type.mbminlen = 0;
		field->type.mbmaxlen = 0;

		cur_len += len;
		dfield_dup(field, buf->heap);

		++field;

		/* The third field is the position.
		MySQL 5.7 changed the fulltext parser plugin interface
		by adding MYSQL_FTPARSER_BOOLEAN_INFO::position.
		Below we assume that the field is always 0. */
		unsigned	pos = t_ctx->init_pos;
		byte		position[4];
		if (parser == NULL) {
			pos += t_ctx->processed_len + inc - str.f_len;
		}
		len = 4;
		mach_write_to_4(position, pos);
		dfield_set_data(field, &position, len);

		field->type.mtype = DATA_INT;
		field->type.prtype = DATA_NOT_NULL;
		field->type.len = len;
		field->type.mbminlen = 0;
		field->type.mbmaxlen = 0;
		cur_len += len;
		dfield_dup(field, buf->heap);

		/* Reserve one byte for the end marker of row_merge_block_t */
		if (buf->total_size + data_size[idx] + cur_len
		    >= srv_sort_buf_size - 1) {

			buf_full = TRUE;
			break;
		}

		/* Increment the number of tuples */
		n_tuple[idx]++;
		if (parser != NULL) {
			UT_LIST_REMOVE(t_ctx->fts_token_list, fts_token);
			ut_free(fts_token);
		} else {
			t_ctx->processed_len += inc;
		}
		data_size[idx] += cur_len;
	}

	/* Update the data length and the number of new word tuples
	added in this round of tokenization */
	for (ulint i = 0; i <  FTS_NUM_AUX_INDEX; i++) {
		/* The computation of total_size below assumes that no
		delete-mark flags will be stored and that all fields
		are NOT NULL and fixed-length. */

		sort_buf[i]->total_size += data_size[i];

		sort_buf[i]->n_tuples += n_tuple[i];

		merge_file[i]->n_rec += n_tuple[i];
		t_ctx->rows_added[i] += n_tuple[i];
	}

	if (!buf_full) {
		/* we pad one byte between text accross two fields */
		t_ctx->init_pos += doc->text.f_len + 1;
	}

	return(!buf_full);
}

/*********************************************************************//**
Get next doc item from fts_doc_list */
UNIV_INLINE
void
row_merge_fts_get_next_doc_item(
/*============================*/
	fts_psort_t*		psort_info,	/*!< in: psort_info */
	fts_doc_item_t**	doc_item)	/*!< in/out: doc item */
{
	if (*doc_item != NULL) {
		ut_free(*doc_item);
	}

	mutex_enter(&psort_info->mutex);

	*doc_item = UT_LIST_GET_FIRST(psort_info->fts_doc_list);
	if (*doc_item != NULL) {
		UT_LIST_REMOVE(psort_info->fts_doc_list, *doc_item);

		ut_ad(psort_info->memory_used >= sizeof(fts_doc_item_t)
		      + (*doc_item)->field->len);
		psort_info->memory_used -= sizeof(fts_doc_item_t)
			+ (*doc_item)->field->len;
	}

	mutex_exit(&psort_info->mutex);
}

/*********************************************************************//**
Function performs parallel tokenization of the incoming doc strings.
It also performs the initial in memory sort of the parsed records.
@return OS_THREAD_DUMMY_RETURN */
static
os_thread_ret_t
fts_parallel_tokenization(
/*======================*/
	void*		arg)	/*!< in: psort_info for the thread */
{
	fts_psort_t*		psort_info = (fts_psort_t*) arg;
	ulint			i;
	fts_doc_item_t*		doc_item = NULL;
	row_merge_buf_t**	buf;
	ibool			processed = FALSE;
	merge_file_t**		merge_file;
	row_merge_block_t**	block;
	row_merge_block_t**	crypt_block;
	int			tmpfd[FTS_NUM_AUX_INDEX];
	ulint			mycount[FTS_NUM_AUX_INDEX];
	ib_uint64_t		total_rec = 0;
	ulint			num_doc_processed = 0;
	doc_id_t		last_doc_id = 0;
	mem_heap_t*		blob_heap = NULL;
	fts_doc_t		doc;
	dict_table_t*		table = psort_info->psort_common->new_table;
	fts_tokenize_ctx_t	t_ctx;
	ulint			retried = 0;
	dberr_t			error = DB_SUCCESS;

	ut_ad(psort_info->psort_common->trx->mysql_thd != NULL);

	/* const char*		path = thd_innodb_tmpdir(
		psort_info->psort_common->trx->mysql_thd);
	*/

	ut_ad(psort_info->psort_common->trx->mysql_thd != NULL);

	const char*		path = thd_innodb_tmpdir(
		psort_info->psort_common->trx->mysql_thd);

	ut_ad(psort_info);

	buf = psort_info->merge_buf;
	merge_file = psort_info->merge_file;
	blob_heap = mem_heap_create(512);
	memset(&doc, 0, sizeof(doc));
	memset(mycount, 0, FTS_NUM_AUX_INDEX * sizeof(int));

	doc.charset = fts_index_get_charset(
		psort_info->psort_common->dup->index);

	block = psort_info->merge_block;
	crypt_block = psort_info->crypt_block;

	const page_size_t&	page_size = dict_table_page_size(table);

	row_merge_fts_get_next_doc_item(psort_info, &doc_item);

	t_ctx.cached_stopword = table->fts->cache->stopword_info.cached_stopword;
	processed = TRUE;
loop:
	while (doc_item) {
		dfield_t*	dfield = doc_item->field;

		last_doc_id = doc_item->doc_id;

		ut_ad (dfield->data != NULL
		       && dfield_get_len(dfield) != UNIV_SQL_NULL);

		/* If finish processing the last item, update "doc" with
		strings in the doc_item, otherwise continue processing last
		item */
		if (processed) {
			byte*		data;
			ulint		data_len;

			dfield = doc_item->field;
			data = static_cast<byte*>(dfield_get_data(dfield));
			data_len = dfield_get_len(dfield);

			if (dfield_is_ext(dfield)) {
				doc.text.f_str =
					btr_copy_externally_stored_field(
						&doc.text.f_len, data,
						page_size, data_len, blob_heap);
			} else {
				doc.text.f_str = data;
				doc.text.f_len = data_len;
			}

			doc.tokens = 0;
			t_ctx.processed_len = 0;
		} else {
			/* Not yet finish processing the "doc" on hand,
			continue processing it */
			ut_ad(doc.text.f_str);
			ut_ad(t_ctx.processed_len < doc.text.f_len);
		}

		processed = row_merge_fts_doc_tokenize(
			buf, doc_item->doc_id, &doc,
			merge_file, psort_info->psort_common->opt_doc_id_size,
			&t_ctx);

		/* Current sort buffer full, need to recycle */
		if (!processed) {
			ut_ad(t_ctx.processed_len < doc.text.f_len);
			ut_ad(t_ctx.rows_added[t_ctx.buf_used]);
			break;
		}

		num_doc_processed++;

		if (fts_enable_diag_print && num_doc_processed % 10000 == 1) {
			ib::info() << "Number of documents processed: "
				<< num_doc_processed;
#ifdef FTS_INTERNAL_DIAG_PRINT
			for (i = 0; i < FTS_NUM_AUX_INDEX; i++) {
				ib::info() << "ID " << psort_info->psort_id
					<< ", partition " << i << ", word "
					<< mycount[i];
			}
#endif
		}

		mem_heap_empty(blob_heap);

		row_merge_fts_get_next_doc_item(psort_info, &doc_item);

		if (doc_item && last_doc_id != doc_item->doc_id) {
			t_ctx.init_pos = 0;
		}
	}

	/* If we run out of current sort buffer, need to sort
	and flush the sort buffer to disk */
	if (t_ctx.rows_added[t_ctx.buf_used] && !processed) {
		row_merge_buf_sort(buf[t_ctx.buf_used], NULL);
		row_merge_buf_write(buf[t_ctx.buf_used],
				    merge_file[t_ctx.buf_used],
				    block[t_ctx.buf_used]);

		if (!row_merge_write(merge_file[t_ctx.buf_used]->fd,
				     merge_file[t_ctx.buf_used]->offset++,
				     block[t_ctx.buf_used],
				     crypt_block[t_ctx.buf_used],
				     table->space)) {
			error = DB_TEMP_FILE_WRITE_FAIL;
			goto func_exit;
		}

		UNIV_MEM_INVALID(block[t_ctx.buf_used][0], srv_sort_buf_size);
		buf[t_ctx.buf_used] = row_merge_buf_empty(buf[t_ctx.buf_used]);
		mycount[t_ctx.buf_used] += t_ctx.rows_added[t_ctx.buf_used];
		t_ctx.rows_added[t_ctx.buf_used] = 0;

		ut_a(doc_item);
		goto loop;
	}

	/* Parent done scanning, and if finish processing all the docs, exit */
	if (psort_info->state == FTS_PARENT_COMPLETE) {
		if (UT_LIST_GET_LEN(psort_info->fts_doc_list) == 0) {
			goto exit;
		} else if (retried > 10000) {
			ut_ad(!doc_item);
			/* retried too many times and cannot get new record */
			ib::error() << "FTS parallel sort processed "
				<< num_doc_processed
				<< " records, the sort queue has "
				<< UT_LIST_GET_LEN(psort_info->fts_doc_list)
				<< " records. But sort cannot get the next"
				" records";
			goto exit;
		}
	} else if (psort_info->state == FTS_PARENT_EXITING) {
		/* Parent abort */
		goto func_exit;
	}

	if (doc_item == NULL) {
		os_thread_yield();
	}

	row_merge_fts_get_next_doc_item(psort_info, &doc_item);

	if (doc_item != NULL) {
		if (last_doc_id != doc_item->doc_id) {
			t_ctx.init_pos = 0;
		}

		retried = 0;
	} else if (psort_info->state == FTS_PARENT_COMPLETE) {
		retried++;
	}

	goto loop;

exit:
	/* Do a final sort of the last (or latest) batch of records
	in block memory. Flush them to temp file if records cannot
	be hold in one block memory */
	for (i = 0; i < FTS_NUM_AUX_INDEX; i++) {
		if (t_ctx.rows_added[i]) {
			row_merge_buf_sort(buf[i], NULL);
			row_merge_buf_write(
				buf[i], merge_file[i], block[i]);

			/* Write to temp file, only if records have
			been flushed to temp file before (offset > 0):
			The pseudo code for sort is following:

				while (there are rows) {
					tokenize rows, put result in block[]
					if (block[] runs out) {
						sort rows;
						write to temp file with
						row_merge_write();
						offset++;
					}
				}

				# write out the last batch
				if (offset > 0) {
					row_merge_write();
					offset++;
				} else {
					# no need to write anything
					offset stay as 0
				}

			so if merge_file[i]->offset is 0 when we come to
			here as the last batch, this means rows have
			never flush to temp file, it can be held all in
			memory */
			if (merge_file[i]->offset != 0) {
				if (!row_merge_write(merge_file[i]->fd,
						merge_file[i]->offset++,
						block[i],
						crypt_block[i],
						table->space)) {
					error = DB_TEMP_FILE_WRITE_FAIL;
					goto func_exit;
				}

				UNIV_MEM_INVALID(block[i][0],
						 srv_sort_buf_size);

				if (crypt_block[i]) {
					UNIV_MEM_INVALID(crypt_block[i][0],
						 srv_sort_buf_size);
				}
			}

			buf[i] = row_merge_buf_empty(buf[i]);
			t_ctx.rows_added[i] = 0;
		}
	}

	if (fts_enable_diag_print) {
		DEBUG_FTS_SORT_PRINT("  InnoDB_FTS: start merge sort\n");
	}

	for (i = 0; i < FTS_NUM_AUX_INDEX; i++) {
		if (!merge_file[i]->offset) {
			continue;
		}

		tmpfd[i] = row_merge_file_create_low(path);
		if (tmpfd[i] < 0) {
			error = DB_OUT_OF_MEMORY;
			goto func_exit;
		}

		error = row_merge_sort(psort_info->psort_common->trx,
				       psort_info->psort_common->dup,
				       merge_file[i], block[i], &tmpfd[i],
				       false, 0.0/* pct_progress */, 0.0/* pct_cost */,
				       crypt_block[i], table->space);

		if (error != DB_SUCCESS) {
			close(tmpfd[i]);
			goto func_exit;
		}

		total_rec += merge_file[i]->n_rec;
		close(tmpfd[i]);
	}

func_exit:
	if (fts_enable_diag_print) {
		DEBUG_FTS_SORT_PRINT("  InnoDB_FTS: complete merge sort\n");
	}

	mem_heap_free(blob_heap);

	mutex_enter(&psort_info->mutex);
	psort_info->error = error;
	mutex_exit(&psort_info->mutex);

	if (UT_LIST_GET_LEN(psort_info->fts_doc_list) > 0) {
		/* child can exit either with error or told by parent. */
		ut_ad(error != DB_SUCCESS
		      || psort_info->state == FTS_PARENT_EXITING);
	}

	/* Free fts doc list in case of error. */
	do {
		row_merge_fts_get_next_doc_item(psort_info, &doc_item);
	} while (doc_item != NULL);

	psort_info->child_status = FTS_CHILD_COMPLETE;
	os_event_set(psort_info->psort_common->sort_event);
	psort_info->child_status = FTS_CHILD_EXITING;

	os_thread_exit();

	OS_THREAD_DUMMY_RETURN;
}

/*********************************************************************//**
Start the parallel tokenization and parallel merge sort */
void
row_fts_start_psort(
/*================*/
	fts_psort_t*	psort_info)	/*!< parallel sort structure */
{
	ulint		i = 0;
	os_thread_id_t	thd_id;

	for (i = 0; i < fts_sort_pll_degree; i++) {
		psort_info[i].psort_id = i;
		psort_info[i].thread_hdl =
			os_thread_create(fts_parallel_tokenization,
				(void*) &psort_info[i],
				 &thd_id);
	}
}

/*********************************************************************//**
Function performs the merge and insertion of the sorted records.
@return OS_THREAD_DUMMY_RETURN */
static
os_thread_ret_t
fts_parallel_merge(
/*===============*/
	void*		arg)		/*!< in: parallel merge info */
{
	fts_psort_t*	psort_info = (fts_psort_t*) arg;
	ulint		id;

	ut_ad(psort_info);

	id = psort_info->psort_id;

	row_fts_merge_insert(psort_info->psort_common->dup->index,
			     psort_info->psort_common->new_table,
			     psort_info->psort_common->all_info, id);

	psort_info->child_status = FTS_CHILD_COMPLETE;
	os_event_set(psort_info->psort_common->merge_event);
	psort_info->child_status = FTS_CHILD_EXITING;

	os_thread_exit(false);

	OS_THREAD_DUMMY_RETURN;
}

/*********************************************************************//**
Kick off the parallel merge and insert thread */
void
row_fts_start_parallel_merge(
/*=========================*/
	fts_psort_t*	merge_info)	/*!< in: parallel sort info */
{
	int		i = 0;

	/* Kick off merge/insert threads */
	for (i = 0; i <  FTS_NUM_AUX_INDEX; i++) {
		merge_info[i].psort_id = i;
		merge_info[i].child_status = 0;

		merge_info[i].thread_hdl = os_thread_create(
			fts_parallel_merge,
			(void*) &merge_info[i],
			&merge_info[i].thread_hdl);
	}
}

/**
Write out a single word's data as new entry/entries in the INDEX table.
@param[in]	ins_ctx	insert context
@param[in]	word	word string
@param[in]	node	node colmns
@return	DB_SUCCUESS if insertion runs fine, otherwise error code */
static
dberr_t
row_merge_write_fts_node(
	const	fts_psort_insert_t*	ins_ctx,
	const	fts_string_t*		word,
	const	fts_node_t*		node)
{
	dtuple_t*	tuple;
	dfield_t*	field;
	dberr_t		ret = DB_SUCCESS;
	doc_id_t	write_first_doc_id[8];
	doc_id_t	write_last_doc_id[8];
	ib_uint32_t	write_doc_count;

	tuple = ins_ctx->tuple;

	/* The first field is the tokenized word */
	field = dtuple_get_nth_field(tuple, 0);
	dfield_set_data(field, word->f_str, word->f_len);

	/* The second field is first_doc_id */
	field = dtuple_get_nth_field(tuple, 1);
	fts_write_doc_id((byte*)&write_first_doc_id, node->first_doc_id);
	dfield_set_data(field, &write_first_doc_id, sizeof(doc_id_t));

	/* The third and fourth fileds(TRX_ID, ROLL_PTR) are filled already.*/
	/* The fifth field is last_doc_id */
	field = dtuple_get_nth_field(tuple, 4);
	fts_write_doc_id((byte*)&write_last_doc_id, node->last_doc_id);
	dfield_set_data(field, &write_last_doc_id, sizeof(doc_id_t));

	/* The sixth field is doc_count */
	field = dtuple_get_nth_field(tuple, 5);
	mach_write_to_4((byte*)&write_doc_count, (ib_uint32_t)node->doc_count);
	dfield_set_data(field, &write_doc_count, sizeof(ib_uint32_t));

	/* The seventh field is ilist */
	field = dtuple_get_nth_field(tuple, 6);
	dfield_set_data(field, node->ilist, node->ilist_size);

	ret = ins_ctx->btr_bulk->insert(tuple);

	return(ret);
}

/********************************************************************//**
Insert processed FTS data to auxillary index tables.
@return DB_SUCCESS if insertion runs fine */
static MY_ATTRIBUTE((nonnull))
dberr_t
row_merge_write_fts_word(
/*=====================*/
	fts_psort_insert_t*	ins_ctx,	/*!< in: insert context */
	fts_tokenizer_word_t*	word)		/*!< in: sorted and tokenized
						word */
{
	dberr_t	ret = DB_SUCCESS;

	ut_ad(ins_ctx->aux_index_id == fts_select_index(
		ins_ctx->charset, word->text.f_str, word->text.f_len));

	/* Pop out each fts_node in word->nodes write them to auxiliary table */
	for (ulint i = 0; i < ib_vector_size(word->nodes); i++) {
		dberr_t		error;
		fts_node_t*	fts_node;

		fts_node = static_cast<fts_node_t*>(ib_vector_get(word->nodes, i));

		error = row_merge_write_fts_node(ins_ctx, &word->text, fts_node);

		if (error != DB_SUCCESS) {
			ib::error() << "Failed to write word "
				<< word->text.f_str << " to FTS auxiliary"
				" index table, error (" << ut_strerr(error)
				<< ")";
			ret = error;
		}

		ut_free(fts_node->ilist);
		fts_node->ilist = NULL;
	}

	ib_vector_reset(word->nodes);

	return(ret);
}

/*********************************************************************//**
Read sorted FTS data files and insert data tuples to auxillary tables.
@return DB_SUCCESS or error number */
static
void
row_fts_insert_tuple(
/*=================*/
	fts_psort_insert_t*
			ins_ctx,	/*!< in: insert context */
	fts_tokenizer_word_t* word,	/*!< in: last processed
					tokenized word */
	ib_vector_t*	positions,	/*!< in: word position */
	doc_id_t*	in_doc_id,	/*!< in: last item doc id */
	dtuple_t*	dtuple)		/*!< in: entry to insert */
{
	fts_node_t*	fts_node = NULL;
	dfield_t*	dfield;
	doc_id_t	doc_id;
	ulint		position;
	fts_string_t	token_word;
	ulint		i;

	/* Get fts_node for the FTS auxillary INDEX table */
	if (ib_vector_size(word->nodes) > 0) {
		fts_node = static_cast<fts_node_t*>(
			ib_vector_last(word->nodes));
	}

	if (fts_node == NULL
	    || fts_node->ilist_size > FTS_ILIST_MAX_SIZE) {

		fts_node = static_cast<fts_node_t*>(
			ib_vector_push(word->nodes, NULL));

		memset(fts_node, 0x0, sizeof(*fts_node));
	}

	/* If dtuple == NULL, this is the last word to be processed */
	if (!dtuple) {
		if (fts_node && ib_vector_size(positions) > 0) {
			fts_cache_node_add_positions(
				NULL, fts_node, *in_doc_id,
				positions);

			/* Write out the current word */
			row_merge_write_fts_word(ins_ctx, word);
		}

		return;
	}

	/* Get the first field for the tokenized word */
	dfield = dtuple_get_nth_field(dtuple, 0);

	token_word.f_n_char = 0;
	token_word.f_len = dfield->len;
	token_word.f_str = static_cast<byte*>(dfield_get_data(dfield));

	if (!word->text.f_str) {
		fts_string_dup(&word->text, &token_word, ins_ctx->heap);
	}

	/* compare to the last word, to see if they are the same
	word */
	if (innobase_fts_text_cmp(ins_ctx->charset,
				  &word->text, &token_word) != 0) {
		ulint	num_item;

		/* Getting a new word, flush the last position info
		for the currnt word in fts_node */
		if (ib_vector_size(positions) > 0) {
			fts_cache_node_add_positions(
				NULL, fts_node, *in_doc_id, positions);
		}

		/* Write out the current word */
		row_merge_write_fts_word(ins_ctx, word);

		/* Copy the new word */
		fts_string_dup(&word->text, &token_word, ins_ctx->heap);

		num_item = ib_vector_size(positions);

		/* Clean up position queue */
		for (i = 0; i < num_item; i++) {
			ib_vector_pop(positions);
		}

		/* Reset Doc ID */
		*in_doc_id = 0;
		memset(fts_node, 0x0, sizeof(*fts_node));
	}

	/* Get the word's Doc ID */
	dfield = dtuple_get_nth_field(dtuple, 1);

	if (!ins_ctx->opt_doc_id_size) {
		doc_id = fts_read_doc_id(
			static_cast<byte*>(dfield_get_data(dfield)));
	} else {
		doc_id = (doc_id_t) mach_read_from_4(
			static_cast<byte*>(dfield_get_data(dfield)));
	}

	/* Get the word's position info */
	dfield = dtuple_get_nth_field(dtuple, 2);
	position = mach_read_from_4(static_cast<byte*>(dfield_get_data(dfield)));

	/* If this is the same word as the last word, and they
	have the same Doc ID, we just need to add its position
	info. Otherwise, we will flush position info to the
	fts_node and initiate a new position vector  */
	if (!(*in_doc_id) || *in_doc_id == doc_id) {
		ib_vector_push(positions, &position);
	} else {
		ulint	num_pos = ib_vector_size(positions);

		fts_cache_node_add_positions(NULL, fts_node,
					     *in_doc_id, positions);
		for (i = 0; i < num_pos; i++) {
			ib_vector_pop(positions);
		}
		ib_vector_push(positions, &position);
	}

	/* record the current Doc ID */
	*in_doc_id = doc_id;
}

/*********************************************************************//**
Propagate a newly added record up one level in the selection tree
@return parent where this value propagated to */
static
int
row_fts_sel_tree_propagate(
/*=======================*/
	int		propogated,	/*<! in: tree node propagated */
	int*		sel_tree,	/*<! in: selection tree */
	const mrec_t**	mrec,		/*<! in: sort record */
	ulint**		offsets,	/*<! in: record offsets */
	dict_index_t*	index)		/*<! in/out: FTS index */
{
	ulint	parent;
	int	child_left;
	int	child_right;
	int	selected;

	/* Find which parent this value will be propagated to */
	parent = (propogated - 1) / 2;

	/* Find out which value is smaller, and to propagate */
	child_left = sel_tree[parent * 2 + 1];
	child_right = sel_tree[parent * 2 + 2];

	if (child_left == -1 || mrec[child_left] == NULL) {
		if (child_right == -1
		    || mrec[child_right] == NULL) {
			selected = -1;
		} else {
			selected = child_right ;
		}
	} else if (child_right == -1
		   || mrec[child_right] == NULL) {
		selected = child_left;
	} else if (cmp_rec_rec_simple(mrec[child_left], mrec[child_right],
				      offsets[child_left],
				      offsets[child_right],
				      index, NULL) < 0) {
		selected = child_left;
	} else {
		selected = child_right;
	}

	sel_tree[parent] = selected;

	return(static_cast<int>(parent));
}

/*********************************************************************//**
Readjust selection tree after popping the root and read a new value
@return the new root */
static
int
row_fts_sel_tree_update(
/*====================*/
	int*		sel_tree,	/*<! in/out: selection tree */
	ulint		propagated,	/*<! in: node to propagate up */
	ulint		height,		/*<! in: tree height */
	const mrec_t**	mrec,		/*<! in: sort record */
	ulint**		offsets,	/*<! in: record offsets */
	dict_index_t*	index)		/*<! in: index dictionary */
{
	ulint	i;

	for (i = 1; i <= height; i++) {
		propagated = static_cast<ulint>(row_fts_sel_tree_propagate(
			static_cast<int>(propagated), sel_tree, mrec, offsets, index));
	}

	return(sel_tree[0]);
}

/*********************************************************************//**
Build selection tree at a specified level */
static
void
row_fts_build_sel_tree_level(
/*=========================*/
	int*		sel_tree,	/*<! in/out: selection tree */
	ulint		level,		/*<! in: selection tree level */
	const mrec_t**	mrec,		/*<! in: sort record */
	ulint**		offsets,	/*<! in: record offsets */
	dict_index_t*	index)		/*<! in: index dictionary */
{
	ulint	start;
	int	child_left;
	int	child_right;
	ulint	i;
	ulint	num_item	= ulint(1) << level;

	start = num_item - 1;

	for (i = 0; i < num_item;  i++) {
		child_left = sel_tree[(start + i) * 2 + 1];
		child_right = sel_tree[(start + i) * 2 + 2];

		if (child_left == -1) {
			if (child_right == -1) {
				sel_tree[start + i] = -1;
			} else {
				sel_tree[start + i] =  child_right;
			}
			continue;
		} else if (child_right == -1) {
			sel_tree[start + i] = child_left;
			continue;
		}

		/* Deal with NULL child conditions */
		if (!mrec[child_left]) {
			if (!mrec[child_right]) {
				sel_tree[start + i] = -1;
			} else {
				sel_tree[start + i] = child_right;
			}
			continue;
		} else if (!mrec[child_right]) {
			sel_tree[start + i] = child_left;
			continue;
		}

		/* Select the smaller one to set parent pointer */
		int cmp = cmp_rec_rec_simple(
			mrec[child_left], mrec[child_right],
			offsets[child_left], offsets[child_right],
			index, NULL);

		sel_tree[start + i] = cmp < 0 ? child_left : child_right;
	}
}

/*********************************************************************//**
Build a selection tree for merge. The selection tree is a binary tree
and should have fts_sort_pll_degree / 2 levels. With root as level 0
@return number of tree levels */
static
ulint
row_fts_build_sel_tree(
/*===================*/
	int*		sel_tree,	/*<! in/out: selection tree */
	const mrec_t**	mrec,		/*<! in: sort record */
	ulint**		offsets,	/*<! in: record offsets */
	dict_index_t*	index)		/*<! in: index dictionary */
{
	ulint	treelevel = 1;
	ulint	num = 2;
	int	i = 0;
	ulint	start;

	/* No need to build selection tree if we only have two merge threads */
	if (fts_sort_pll_degree <= 2) {
		return(0);
	}

	while (num < fts_sort_pll_degree) {
		num = num << 1;
		treelevel++;
	}

	start = (ulint(1) << treelevel) - 1;

	for (i = 0; i < (int) fts_sort_pll_degree; i++) {
		sel_tree[i + start] = i;
	}

	for (i = static_cast<int>(treelevel) - 1; i >= 0; i--) {
		row_fts_build_sel_tree_level(
			sel_tree, static_cast<ulint>(i), mrec, offsets, index);
	}

	return(treelevel);
}

/*********************************************************************//**
Read sorted file containing index data tuples and insert these data
tuples to the index
@return DB_SUCCESS or error number */
dberr_t
row_fts_merge_insert(
/*=================*/
	dict_index_t*		index,	/*!< in: index */
	dict_table_t*		table,	/*!< in: new table */
	fts_psort_t*		psort_info, /*!< parallel sort info */
	ulint			id)	/* !< in: which auxiliary table's data
					to insert to */
{
	const byte**		b;
	mem_heap_t*		tuple_heap;
	mem_heap_t*		heap;
	dberr_t			error = DB_SUCCESS;
	ulint*			foffs;
	ulint**			offsets;
	fts_tokenizer_word_t	new_word;
	ib_vector_t*		positions;
	doc_id_t		last_doc_id;
	ib_alloc_t*		heap_alloc;
	ulint			i;
	mrec_buf_t**		buf;
	int*			fd;
	byte**			block;
	byte**			crypt_block;
	const mrec_t**		mrec;
	ulint			count = 0;
	int*			sel_tree;
	ulint			height;
	ulint			start;
	fts_psort_insert_t	ins_ctx;
	ulint			count_diag = 0;
	fts_table_t		fts_table;
	char			aux_table_name[MAX_FULL_NAME_LEN];
	dict_table_t*		aux_table;
	dict_index_t*		aux_index;
	trx_t*			trx;
	byte			trx_id_buf[6];
	roll_ptr_t		roll_ptr = 0;
	dfield_t*		field;

	ut_ad(index);
	ut_ad(table);

	/* We use the insert query graph as the dummy graph
	needed in the row module call */

	trx = trx_allocate_for_background();
	trx_start_if_not_started(trx, true);

	trx->op_info = "inserting index entries";

	ins_ctx.opt_doc_id_size = psort_info[0].psort_common->opt_doc_id_size;

	heap = mem_heap_create(500 + sizeof(mrec_buf_t));

	b = (const byte**) mem_heap_alloc(
		heap, sizeof (*b) * fts_sort_pll_degree);
	foffs = (ulint*) mem_heap_alloc(
		heap, sizeof(*foffs) * fts_sort_pll_degree);
	offsets = (ulint**) mem_heap_alloc(
		heap, sizeof(*offsets) * fts_sort_pll_degree);
	buf = (mrec_buf_t**) mem_heap_alloc(
		heap, sizeof(*buf) * fts_sort_pll_degree);
	fd = (int*) mem_heap_alloc(heap, sizeof(*fd) * fts_sort_pll_degree);
	block = (byte**) mem_heap_alloc(
		heap, sizeof(*block) * fts_sort_pll_degree);
	crypt_block = (byte**) mem_heap_alloc(
		heap, sizeof(*block) * fts_sort_pll_degree);
	mrec = (const mrec_t**) mem_heap_alloc(
		heap, sizeof(*mrec) * fts_sort_pll_degree);
	sel_tree = (int*) mem_heap_alloc(
		heap, sizeof(*sel_tree) * (fts_sort_pll_degree * 2));

	tuple_heap = mem_heap_create(1000);

	ins_ctx.charset = fts_index_get_charset(index);
	ins_ctx.heap = heap;

	for (i = 0; i < fts_sort_pll_degree; i++) {
		ulint	num;

		num = 1 + REC_OFFS_HEADER_SIZE
			+ dict_index_get_n_fields(index);
		offsets[i] = static_cast<ulint*>(mem_heap_zalloc(
			heap, num * sizeof *offsets[i]));
		offsets[i][0] = num;
		offsets[i][1] = dict_index_get_n_fields(index);
		block[i] = psort_info[i].merge_block[id];
		crypt_block[i] = psort_info[i].crypt_block[id];
		b[i] = psort_info[i].merge_block[id];
		fd[i] = psort_info[i].merge_file[id]->fd;
		foffs[i] = 0;

		buf[i] = static_cast<mrec_buf_t*>(
			mem_heap_alloc(heap, sizeof *buf[i]));

		count_diag += (int) psort_info[i].merge_file[id]->n_rec;
	}

	if (fts_enable_diag_print) {
		ib::info() << "InnoDB_FTS: to insert " << count_diag
			<< " records";
	}

	/* Initialize related variables if creating FTS indexes */
	heap_alloc = ib_heap_allocator_create(heap);

	memset(&new_word, 0, sizeof(new_word));

	new_word.nodes = ib_vector_create(heap_alloc, sizeof(fts_node_t), 4);
	positions = ib_vector_create(heap_alloc, sizeof(ulint), 32);
	last_doc_id = 0;

	/* We should set the flags2 with aux_table_name here,
	in order to get the correct aux table names. */
	index->table->flags2 |= DICT_TF2_FTS_AUX_HEX_NAME;
	DBUG_EXECUTE_IF("innodb_test_wrong_fts_aux_table_name",
			index->table->flags2 &= ~DICT_TF2_FTS_AUX_HEX_NAME;);
	fts_table.type = FTS_INDEX_TABLE;
	fts_table.index_id = index->id;
	fts_table.table_id = table->id;
	fts_table.parent = index->table->name.m_name;
	fts_table.table = index->table;
	fts_table.suffix = fts_get_suffix(id);

	/* Get aux index */
	fts_get_table_name(&fts_table, aux_table_name);
	aux_table = dict_table_open_on_name(aux_table_name, FALSE, FALSE,
					    DICT_ERR_IGNORE_NONE);
	ut_ad(aux_table != NULL);
	dict_table_close(aux_table, FALSE, FALSE);
	aux_index = dict_table_get_first_index(aux_table);

	/* Create bulk load instance */
	ins_ctx.btr_bulk = UT_NEW_NOKEY(
		BtrBulk(aux_index, trx, psort_info[0].psort_common->trx
			->flush_observer));

	/* Create tuple for insert */
	ins_ctx.tuple = dtuple_create(heap, dict_index_get_n_fields(aux_index));
	dict_index_copy_types(ins_ctx.tuple, aux_index,
			      dict_index_get_n_fields(aux_index));

	/* Set TRX_ID and ROLL_PTR */
	trx_write_trx_id(trx_id_buf, trx->id);
	field = dtuple_get_nth_field(ins_ctx.tuple, 2);
	dfield_set_data(field, &trx_id_buf, 6);

	field = dtuple_get_nth_field(ins_ctx.tuple, 3);
	dfield_set_data(field, &roll_ptr, 7);

#ifdef UNIV_DEBUG
	ins_ctx.aux_index_id = id;
#endif
	const ulint space = table->space;

	for (i = 0; i < fts_sort_pll_degree; i++) {
		if (psort_info[i].merge_file[id]->n_rec == 0) {
			/* No Rows to read */
			mrec[i] = b[i] = NULL;
		} else {
			/* Read from temp file only if it has been
			written to. Otherwise, block memory holds
			all the sorted records */
			if (psort_info[i].merge_file[id]->offset > 0
			    && (!row_merge_read(
					fd[i], foffs[i],
					(row_merge_block_t*) block[i],
					(row_merge_block_t*) crypt_block[i],
					space))) {
				error = DB_CORRUPTION;
				goto exit;
			}

			ROW_MERGE_READ_GET_NEXT(i);
		}
	}

	height = row_fts_build_sel_tree(sel_tree, (const mrec_t **) mrec,
					offsets, index);

	start = (1 << height) - 1;

	/* Fetch sorted records from sort buffer and insert them into
	corresponding FTS index auxiliary tables */
	for (;;) {
		dtuple_t*	dtuple;
		ulint		n_ext;
		int		min_rec = 0;

		if (fts_sort_pll_degree <= 2) {
			while (!mrec[min_rec]) {
				min_rec++;

				if (min_rec >= (int) fts_sort_pll_degree) {
					row_fts_insert_tuple(
						&ins_ctx, &new_word,
						positions, &last_doc_id,
						NULL);

					goto exit;
				}
			}

			for (i = min_rec + 1; i < fts_sort_pll_degree; i++) {
				if (!mrec[i]) {
					continue;
				}

				if (cmp_rec_rec_simple(
					    mrec[i], mrec[min_rec],
					    offsets[i], offsets[min_rec],
					    index, NULL) < 0) {
					min_rec = static_cast<int>(i);
				}
			}
		} else {
			min_rec = sel_tree[0];

			if (min_rec ==  -1) {
				row_fts_insert_tuple(
					&ins_ctx, &new_word,
					positions, &last_doc_id,
					NULL);

				goto exit;
			}
		}

		dtuple = row_rec_to_index_entry_low(
			mrec[min_rec], index, offsets[min_rec], &n_ext,
			tuple_heap);

		row_fts_insert_tuple(
			&ins_ctx, &new_word, positions,
			&last_doc_id, dtuple);


		ROW_MERGE_READ_GET_NEXT(min_rec);

		if (fts_sort_pll_degree > 2) {
			if (!mrec[min_rec]) {
				sel_tree[start + min_rec] = -1;
			}

			row_fts_sel_tree_update(sel_tree, start + min_rec,
						height, mrec,
						offsets, index);
		}

		count++;

		mem_heap_empty(tuple_heap);
	}

exit:
	fts_sql_commit(trx);

	trx->op_info = "";

	mem_heap_free(tuple_heap);

	error = ins_ctx.btr_bulk->finish(error);
	UT_DELETE(ins_ctx.btr_bulk);

	trx_free_for_background(trx);

	mem_heap_free(heap);

	if (fts_enable_diag_print) {
		ib::info() << "InnoDB_FTS: inserted " << count << " records";
	}

	return(error);
}