[Tarantool-patches] [PATCH v1 1/3] sql: fix truncation of DECIMAL in implicit cast

[Mergen Imeev]

Hi! Thank you for the review! My answer and diff below.

On Tue, Oct 05, 2021 at 11:56:08PM +0200, Vladislav Shpilevoy wrote:
> Hi! Thanks for the patchset!
> 
> > diff --git a/test/sql-tap/gh-6485-bugs-in-decimal.test.lua b/test/sql-tap/gh-6485-bugs-in-decimal.test.lua
> > new file mode 100755
> > index 000000000..3f63f2b76
> > --- /dev/null
> > +++ b/test/sql-tap/gh-6485-bugs-in-decimal.test.lua
> > @@ -0,0 +1,16 @@
> > +#!/usr/bin/env tarantool
> > +local test = require("sqltester")
> > +test:plan(1)
> > +
> > +-- Make sure DECIMAL is not truncated when used in an index.
> > +test:do_execsql_test(
> > +    "gh-6485-1",
> > +    [[
> > +        CREATE TABLE t(i INTEGER PRIMARY KEY);
> > +        INSERT INTO t VALUES(1), (2);
> > +        SELECT i FROM t WHERE i IN (CAST(1.1 AS DECIMAL), CAST(2.2 AS DECIMAL));
> > +        DROP TABLE t;
> > +    ]], {
> 
> Could you make the same select without creating a table? The same
> for the tests in the second commit.
> 
Both tests use indexes, so the simplest way is to use spaces. I think it is
possible to create queries that use ephemeral spaces with INTEGER indexes, but
I do not think that they will be simple.

I think I should mention that due to the work of the scheduler, the most common
searches of non-INTEGER values in an INTEGER index do not use the index, even
though the entire infrastructure is ready to use the index. This drastically
reduces the number of tests we can use to test this problem. For example, in
this case, a fullscan will be performed instead of an index search:
box.execute([[CREATE TABLE t(i INT PRIMARY KEY);]])
box.execute([[INSERT INTO t VALUES(1), (2), (3), (4);]])
box.execute([[SELECT i FROM t WHERE i = 3.0;]])

> Also you might want to make the test run only once. Now it is run
> twice with 2 engines.
Thanks, fixed:

diff --git a/test/sql-tap/engine.cfg b/test/sql-tap/engine.cfg
index a6f03307f..9d318a456 100644
--- a/test/sql-tap/engine.cfg
+++ b/test/sql-tap/engine.cfg
@@ -39,6 +39,7 @@
     "gh-6376-wrong-double-to-dec-cmp.test.lua": {},
     "gh-4077-iproto-execute-no-bind.test.lua": {},
     "gh-6375-assert-on-unsupported-ext.test.lua": {},
+    "gh-6485-bugs-in-decimal.test.lua": {},
     "*": {
         "memtx": {"engine": "memtx"},
         "vinyl": {"engine": "vinyl"}