[tarantool-patches] Re: [PATCH 4/5] sql: display error on FK creation and drop failure
Vladislav Shpilevoy
v.shpilevoy at tarantool.org
Wed Jul 18 00:04:56 MSK 2018
Thanks for the patch! See 4 comments below.
On 13/07/2018 05:04, Nikita Pettik wrote:
> Before insertion to _fk_constraint we must be sure that there in no
> entry with given <name, child id>. Otherwise, insertion will fail and
> 'duplicate key' will be shown. Such error message doesn't seem to be
> informative enough, so lets manually iterate through whole space looking
> for appropriate record.
1. As I know, vdbe_emit_halt_with_presence_test do not iterate through
the whole space. It uses an index to search for the record fast.
> The same is for dropping constraint, but here vice versa: we test
> that _fk_contraint contains entry with given name and child id.
2. Typo: _fk_contraint -> _fk_constraint.
>
> It is worth mentioning that during CREATE TABLE processing schema id
> changes and check in OP_OpenRead opcode fails (which in turn shows that
> pointer to space may expire). On the other hand, _fk_constraint space
> itself remains immutable, so as a temporary workaround lets use flag
> indicating pointer to system space passed to OP_OpenRead. It makes
> possible to use pointer to space, even if schema has changed.
>
> Closes #3271
> ---
> src/box/errcode.h | 2 ++
> src/box/sql/build.c | 43 +++++++++++++++++++++++++++++++------------
> src/box/sql/sqliteInt.h | 10 +++++++---
> src/box/sql/trigger.c | 24 ++++++++++++++++--------
> src/box/sql/vdbe.c | 3 ++-
> test/box/misc.result | 2 ++
> test/sql-tap/alter2.test.lua | 25 ++++++++++++++++++++++++-
> 7 files changed, 84 insertions(+), 25 deletions(-)
>
> diff --git a/src/box/sql/build.c b/src/box/sql/build.c
> index c2d3cd035..20ace09e4 100644
> --- a/src/box/sql/build.c
> +++ b/src/box/sql/build.c
> @@ -1784,6 +1784,20 @@ vdbe_fkey_code_creation(struct Parse *parse_context, const struct fkey_def *fk)
> sqlite3VdbeAddOp2(vdbe, OP_Integer, fk->parent_id,
> constr_tuple_reg + 2);
> }
> + /*
> + * Lets check that constraint with this name hasn't
> + * been created before.
> + */
> + const char *error_msg =
> + tt_sprintf(tnt_errcode_desc(ER_CONSTRAINT_EXISTS), name_copy);
> + if (vdbe_emit_halt_with_presence_test(parse_context,
> + BOX_FK_CONSTRAINT_ID, 0,
> + constr_tuple_reg, 2,
> + ER_CONSTRAINT_EXISTS, error_msg,
> + false, OP_NoConflict) != 0) {
> + free((void *) name_copy);
3. Name_copy is allocated on db.
> + return;
> + }
> diff --git a/src/box/sql/vdbe.c b/src/box/sql/vdbe.c
> index b9723e2e7..0f227e637 100644
> --- a/src/box/sql/vdbe.c
> +++ b/src/box/sql/vdbe.c
> @@ -3172,7 +3172,8 @@ case OP_OpenWrite:
> * during runtime.
> */
> if (box_schema_version() != p->schema_ver &&
> - (pOp->p5 & OPFLAG_FRESH_PTR) == 0) {
> + (pOp->p5 & OPFLAG_FRESH_PTR) == 0 &&
> + (pOp->p5 & OPFLAG_SYSTEMSP) == 0) {
4. Why not p5 & (FRESH_PTR | SYSTEMSP) ?
> p->expired = 1;
> rc = SQLITE_ERROR;
> sqlite3VdbeError(p, "schema version has changed: " \
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