Commit 7b07e332 authored by unknown's avatar unknown
Browse files

InnoDB: Reduce memcpy() load in row_sel_pop_cached_row_for_mysql() 

by copying only a prefix of the row that covers the requested
columns.


innobase/include/row0mysql.h:
  row_prebuilt_struct: Add field mysql_prefix_len
  in order to reduce memcpy() time in
  row_sel_pop_cached_row_for_mysql().
innobase/row/row0sel.c:
  row_sel_pop_cached_row_for_mysql(): memcpy() only
  mysql_prefix_len bytes instead of mysql_row_len.
sql/ha_innodb.cc:
  build_template(): Initialize prebuilt->mysql_prefix_len.
parent 4e0e9a3b

innobase/include/row0mysql.h

+2 −0
Original line number Diff line number Diff line
@@ -599,6 +599,8 @@ struct row_prebuilt_struct { 
					that was decided in ha_innodb.cc,

					::store_lock(), ::external_lock(),

					etc. */

	ulint		mysql_prefix_len;/* byte offset of the end of

					the last requested column */

	ulint		mysql_row_len;	/* length in bytes of a row in the

					MySQL format */

	ulint		n_rows_fetched;	/* number of rows fetched after

innobase/row/row0sel.c

+3 −2
Original line number Diff line number Diff line
@@ -2849,8 +2849,9 @@ row_sel_pop_cached_row_for_mysql( 
	mysql_row_templ_t*	templ;

	byte*			cached_rec;

        ut_ad(prebuilt->n_fetch_cached > 0);

	ut_ad(prebuilt->mysql_prefix_len <= prebuilt->mysql_row_len);

	

	if (prebuilt->keep_other_fields_on_keyread)

	if (UNIV_UNLIKELY(prebuilt->keep_other_fields_on_keyread))

	{

		/* Copy cache record field by field, don't touch fields that 

		are not covered by current key */
@@ -2877,7 +2878,7 @@ row_sel_pop_cached_row_for_mysql( 
	else

	{

		ut_memcpy(buf, prebuilt->fetch_cache[prebuilt->fetch_cache_first],

				prebuilt->mysql_row_len);

				prebuilt->mysql_prefix_len);

	}

	prebuilt->n_fetch_cached--;

	prebuilt->fetch_cache_first++;

sql/ha_innodb.cc

+8 −0
Original line number Diff line number Diff line
@@ -2618,6 +2618,8 @@ build_template( 
	ibool		fetch_all_in_key	= FALSE;

	ibool		fetch_primary_key_cols	= FALSE;

	ulint		i;

	/* byte offset of the end of last requested column */

	ulint		mysql_prefix_len	= 0;



	if (prebuilt->select_lock_type == LOCK_X) {

		/* We always retrieve the whole clustered index record if we
@@ -2738,6 +2740,11 @@ build_template( 
					get_field_offset(table, field);



		templ->mysql_col_len = (ulint) field->pack_length();

		if (mysql_prefix_len < templ->mysql_col_offset

				+ templ->mysql_col_len) {

			mysql_prefix_len = templ->mysql_col_offset

				+ templ->mysql_col_len;

		}

		templ->type = index->table->cols[i].type.mtype;

		templ->mysql_type = (ulint)field->type();
@@ -2760,6 +2767,7 @@ build_template( 
	}



	prebuilt->n_template = n_requested_fields;

	prebuilt->mysql_prefix_len = mysql_prefix_len;



	if (index != clust_index && prebuilt->need_to_access_clustered) {

		/* Change rec_field_no's to correspond to the clustered index