[Tarantool-patches] [PATCH v1 1/1] sql: remove OP_Realify
Mergen Imeev
imeevma at tarantool.org
Mon Sep 28 19:41:08 MSK 2020
Hi! Thank you for review! My answer below.
On Mon, Sep 28, 2020 at 03:55:59PM +0000, Nikita Pettik wrote:
> On 26 Sep 17:15, imeevma at tarantool.org wrote:
> > This opcode was used to convert INTEGER values to REAL. It is not
> > necessary in Tarantool and may cause errors.
>
> Add justification: what this change fixes, in which way etc.
>
Fixed:
commit 379694944e39a3b0c33135a724f2ee246c619110
Author: Mergen Imeev <imeevma at gmail.com>
Date: Sat Sep 26 12:43:18 2020 +0300
sql: remove OP_Realify
This opcode was used to convert INTEGER values to REAL. It is not
necessary in Tarantool and causes errors.
Due to OP_Realify two type of errors appeared:
1) In some cases in trigger INTEGER may be converted to DOUBLE.
For example:
box.execute("CREATE TABLE t (i NUMBER PRIMARY KEY, n NUMBER);")
box.execute("CREATE TRIGGER t AFTER INSERT ON t FOR EACH ROW BEGIN UPDATE t SET n = new.n; END;")
box.execute("INSERT INTO t VALUES (1, 1);")
box.execute("SELECT i / 2, n / 2 FROM t;")
Result:
tarantool> box.execute("SELECT i / 2, n / 2 FROM t;")
---
- metadata:
- name: COLUMN_1
type: number
- name: COLUMN_2
type: number
rows:
- [0, 0.5]
...
2) If SELECT uses GROUP BY then it may return DOUBLE instead of INTEGER.
For example:
box.execute("CREATE TABLE t (i NUMBER PRIMARY KEY, n NUMBER);")
box.execute("INSERT INTO t VALUES (1,1);")
box.execute("SELECT i / 2, n / 2 FROM t GROUP BY n;")
Result:
tarantool> box.execute("SELECT i / 2, n / 2 FROM t GROUP BY n;")
---
- metadata:
- name: COLUMN_1
type: number
- name: COLUMN_2
type: number
rows:
- [0.5, 0.5]
...
This patch removes OP_Realify, after which these errors disappear.
Closes #5335
> > Closes #5335
> > ---
> > https://github.com/tarantool/tarantool/issues/5335
> > https://github.com/tarantool/tarantool/tree/imeevma/gh-5335-remove-op-realify
> >
> > @ChangeLog
> > - Fixed a bug with unnecessary convertion from INTEGER to DOUBLE (gh-5335).
> >
> > src/box/sql/delete.c | 12 -----
> > src/box/sql/expr.c | 13 -----
> > src/box/sql/vdbe.c | 17 -------
> > ...-unnecessary-conversation-to-double.result | 51 +++++++++++++++++++
> > ...nnecessary-conversation-to-double.test.lua | 11 ++++
> > 5 files changed, 62 insertions(+), 42 deletions(-)
> > create mode 100644 test/sql/gh-5335-unnecessary-conversation-to-double.result
> > create mode 100644 test/sql/gh-5335-unnecessary-conversation-to-double.test.lua
> >
> > diff --git a/src/box/sql/delete.c b/src/box/sql/delete.c
> > index 68abd1f58..a78c68df6 100644
> > --- a/src/box/sql/delete.c
> > +++ b/src/box/sql/delete.c
> > @@ -565,18 +565,6 @@ sql_generate_index_key(struct Parse *parse, struct index *index, int cursor,
> > }
> > uint32_t tabl_col = index->def->key_def->parts[j].fieldno;
> > sqlVdbeAddOp3(v, OP_Column, cursor, tabl_col, reg_base + j);
> > - /*
> > - * If the column type is NUMBER but the number
> > - * is an integer, then it might be stored in the
> > - * table as an integer (using a compact
> > - * representation) then converted to REAL by an
> > - * OP_Realify opcode. But we are getting
> > - * ready to store this value back into an index,
> > - * where it should be converted by to INTEGER
> > - * again. So omit the OP_Realify opcode if
> > - * it is present
> > - */
> > - sqlVdbeDeletePriorOpcode(v, OP_Realify);
> > }
> > if (reg_out != 0)
> > sqlVdbeAddOp3(v, OP_MakeRecord, reg_base, col_cnt, reg_out);
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