btr0cur.c Improve range size estimate for big ranges (6e553a2c) · Commits · Software / OSDI20 Artifacts / mariadb

BitKeeper/etc/logging_ok

+1 −0

Original line number	Diff line number	Diff line
		jani@hynda.mysql.fi
		heikki@donna.mysql.fi

innobase/btr/btr0cur.c

+11 −0

Original line number	Diff line number	Diff line
		@@ -2351,6 +2351,7 @@ btr_estimate_n_rows_in_range(
		btr_path_t* slot1;
		btr_path_t* slot2;
		ibool diverged;
		ulint divergence_level;
		ulint n_rows;
		ulint i;
		mtr_t mtr;
		@@ -2393,6 +2394,7 @@ btr_estimate_n_rows_in_range(

		n_rows = 1;
		diverged = FALSE;
		divergence_level = 1000000;

		for (i = 0; ; i++) {
		ut_ad(i < BTR_PATH_ARRAY_N_SLOTS);
		@@ -2403,6 +2405,13 @@ btr_estimate_n_rows_in_range(
		if (slot1->nth_rec == ULINT_UNDEFINED
		\|\| slot2->nth_rec == ULINT_UNDEFINED) {

		if (i > divergence_level + 1) {
		/* In trees whose height is > 1 our algorithm
		tends to underestimate: multiply the estimate
		by 2: */

		n_rows = n_rows * 2;
		}
		return(n_rows);
		}

		@@ -2417,6 +2426,8 @@ btr_estimate_n_rows_in_range(
		return(10);
		}

		divergence_level = i;

		diverged = TRUE;
		} else if (diverged) {
		n_rows = (n_rows * (slot1->n_recs + slot2->n_recs))

sql/ha_innobase.cc

+36 −5

Original line number	Diff line number	Diff line
		@@ -822,11 +822,11 @@ ha_innobase::open(

		if (NULL == (ib_table = dict_table_get(norm_name, NULL))) {

		fprintf(stderr, "\
		Cannot find table %s from the internal data dictionary\n\
		of InnoDB though the .frm file for the table exists. Maybe you have deleted\n\
		and created again an InnoDB database but forgotten to delete the\n\
		corresponding .frm files of old InnoDB tables?\n",
		fprintf(stderr,
		"Cannot find table %s from the internal data dictionary\n"
		"of InnoDB though the .frm file for the table exists. Maybe you have deleted\n"
		"and created again an InnoDB database but forgotten to delete the\n"
		"corresponding .frm files of old InnoDB tables?\n",
		norm_name);

		free_share(share);
		@@ -2659,6 +2659,37 @@ ha_innobase::records_in_range(
		DBUG_RETURN((ha_rows) n_rows);
		}

		/*************************************************************************
		Gives an UPPER BOUND to the number of rows in a table. This is used in
		filesort.cc and the upper bound must hold. TODO: Since the number of
		rows in a table may change after this function is called, we still may
		get a 'Sort aborted' error in filesort.cc of MySQL. The ultimate fix is to
		improve the algorithm of filesort.cc. */

		ha_rows
		ha_innobase::estimate_number_of_rows(void)
		/======================================/
		/* out: upper bound of rows, currently 32-bit int
		or uint */
		{
		row_prebuilt_t* prebuilt = (row_prebuilt_t*) innobase_prebuilt;
		dict_table_t* ib_table;

		DBUG_ENTER("info");

		ib_table = prebuilt->table;

		dict_update_statistics(ib_table);

		data_file_length = ((ulonglong)
		ib_table->stat_clustered_index_size)
		* UNIV_PAGE_SIZE;

		/* The minimum clustered index record size is 20 bytes */

		return((ha_rows) (1000 + data_file_length / 20));
		}

		/*************************************************************************
		How many seeks it will take to read through the table. This is to be
		comparable to the number returned by records_in_range so that we can