[tarantool-patches] Re: [PATCH v1 2/4] sql: use 64b bitmasks instead of 32b where possible
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Fri Feb 15 20:05:05 MSK 2019
Thanks for the patch! See 1 comment below.
On 08/02/2019 13:52, Kirill Shcherbatov wrote:
> In some cases(like foreign keys) the SQL code is still used
> 32-bit bit mask, while 64-bit bit masks will perform better
> column optimizations. There was refactored code to work with 64b
> bitmasks where required.
> The 32b bitmasks are still used to specify constant OP_Function
> arguments because this change would require changing the P1 type
> of the VDBE p1 argument, which is not desirable. Moreover, the
> 64 function's arguments is an explicit overkill.
>
> Part of #3571
> ---
> src/box/alter.cc | 10 ++-------
> src/box/sql/delete.c | 8 +++----
> src/box/sql/resolve.c | 19 ++++++-----------
> src/box/sql/sqliteInt.h | 46 +++++++++++++++++++++++------------------
> src/box/sql/trigger.c | 14 ++++++-------
> src/box/sql/update.c | 21 ++++++++-----------
> 6 files changed, 53 insertions(+), 65 deletions(-)
>
> diff --git a/src/box/sql/delete.c b/src/box/sql/delete.c
> index f9c42fdec..5e134ab0c 100644
> --- a/src/box/sql/delete.c
> +++ b/src/box/sql/delete.c
> @@ -484,10 +484,8 @@ sql_generate_row_delete(struct Parse *parse, struct Table *table,
> */
> sqlite3VdbeAddOp2(v, OP_Copy, reg_pk, first_old_reg);
> for (int i = 0; i < (int)table->def->field_count; i++) {
> - testcase(mask != 0xffffffff && iCol == 31);
> - testcase(mask != 0xffffffff && iCol == 32);
> - if (mask == 0xffffffff
> - || (i <= 31 && (mask & MASKBIT32(i)) != 0)) {
> + if (i >= COLUMN_MASK_SIZE ||
> + column_mask_fieldno_is_set(mask, i)) {
Now I see, why did you define COLUMN_MASK_SIZE. And still the problem
is in the way how you understand the last bit.
column_mask_fieldno_is_set() should check, if i >= COLUMN_MASK_SIZE, and in such
a case 'and' it with the last bit. In your code the mask is not 'smart' -
you consider fields >= 63 as set even if the last bit of the mask is 0. It is
worthy of note that literally every place of column_mask_fieldno_is_set() usage
also checks for i >= COLUMN_MASK_SIZE.
> sqlite3ExprCodeGetColumnOfTable(v, table->def,
> cursor, i,
> first_old_reg +
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