Correctness

SQLLogicTests

To measure Dolt's SQL correctness, we test each release of Dolt against a SQL testing suite called sqllogictest. This suite consists of 5.9 million SQL queries and their results, using the results returned by MySQL as a reference. Many of these are randomly generated queries that exercise very complex logic a human would have a hard time reasoning about. They give us greater confidence that the query engine produces correct results for any query, as opposed to just the ones we and our customers have thought to try so far. These tests have exposed many bugs in query execution logic before customers discovered them.

Here's an example of a query run by this test suite:

SELECT pk FROM tab1 WHERE ((((col3 > 0 AND ((col0 >= 7 AND col0 <= 2)
AND (col0 <= 4 OR col4 < 5.82 OR col3 > 7) AND col0 >= 4) AND col0 <
0) AND ((col1 > 7.76))))) OR ((col1 > 7.23 OR (col0 <= 3) OR (col4 >=
2.72 OR col1 >= 8.63) OR (col3 >= 3 AND col3 <= 4)) AND ((col0 < 2 AND
col3 < 0 AND (col1 < 6.30 AND col4 >= 7.2)) AND (((col3 < 5 AND col4
IN (SELECT col1 FROM tab1 WHERE ((col3 >= 7 AND col3 <= 6) OR col0 < 0
OR col1 >= 0.64 OR col3 <= 7 AND (col3 >= 8) AND ((col3 <= 6) AND
((col0 = 1 AND col3 IS NULL)) OR col0 > 7 OR col3 IN (8,1,7,4) OR col3
> 7 AND col3 >= 5 AND (col3 < 0) OR col0 > 3 AND col4 > 1.21 AND col0
< 4 OR ((col4 > 9.30)) AND ((col3 >= 5 AND col3 <= 7))) AND col0 <= 5
OR ((col0 >= 1 AND col4 IS NULL AND col0 > 5 AND (col0 < 3) OR col4 <=
8.86 AND (col3 > 0) AND col3 = 8)) OR col3 >= 1 OR (col3 < 4 OR (col3
= 7 OR (col1 >= 4.84 AND col1 <= 5.61)) OR col3 >= 5 AND ((col3 < 4)
AND ((col3 > 9)) OR (col0 < 3) AND (((col0 IS NULL))) AND (col0 < 4))
AND ((col4 IN (0.79)))) OR (col4 = 6.26 AND col1 >= 5.64) OR col1 IS
NULL AND col0 < 1)))) AND ((((col3 < 9) OR ((col0 IS NULL) OR (((col1
>= 8.40 AND col1 <= 0.30) AND col3 IS NULL OR (col0 <= 7 OR ((col3 >
4))) AND col0 = 6)) OR col3 < 6 AND (((((((col1 > 4.8)) OR col0 < 9 OR
(col3 = 1))) AND col4 >= 4.12))) OR (((col1 > 1.58 AND col0 < 7))) AND
(col1 < 8.60) AND ((col0 > 1 OR col0 > 1 AND ((col3 >= 2 AND col3 <=
0) AND col0 <= 0) OR ((col0 >= 8)) AND (((col3 >= 8 AND col3 <= 8) OR
col0 > 4 OR col3 = 8)) AND col1 > 5.10) AND ((col0 < 7 OR (col0 < 6 OR
(col3 < 0 OR col4 >= 9.51 AND (col3 IS NULL AND col1 < 9.41 AND col1 =
1.9 AND col0 > 1 AND col3 < 9 OR (col4 IS NULL) OR col1 = 0.5 AND
(col0 >= 3) OR col4 = 9.25 OR ((col1 > 0.26)) AND col4 < 8.25 AND
(col0 >= 2) AND col3 IS NULL AND (col1 > 3.52) OR (((col4 < 7.24)) AND
col1 IS NULL) OR col0 > 3) AND col3 >= 4 AND col4 >= 2.5 AND col0 >= 0
OR (col3 > 3 AND col3 >= 3) AND col0 = 1 OR col1 <= 8.9 AND col1 >
9.66 OR (col3 > 9) AND col0 > 0 AND col3 >= 0 AND ((col4 > 8.39))))
AND (col1 IS NULL)))))) AND col1 <= 2.0 OR col4 < 1.8 AND (col4 = 6.59
AND col3 IN (3,9,0))))) OR col4 <= 4.25 OR ((col3 = 5))) OR (((col0 >
0)) AND col0 > 6 AND (col4 >= 6.56)))

Here are Dolt's sqllogictest results for version 1.35.10. Tests that did not run could not complete due to a timeout earlier in the run.

Results	Count
ok	5937457

Correctness Percentage	100.0

Function Coverage

We also measure the coverage of the functions in the SQL engine. This is a measure of how many of the supported MySQL functions are also supported by Dolt.

Here are Dolt's function coverage results for version 1.35.9.

Supported	Total	Percent Coverage
308	438	70

Skipped Engine Tests

Here are the total number of tests skipped by the engine for version 1.35.9. These are edge cases that we know are failing for one reason or another, but haven't been able to fix yet.

In general, these tests are more difficult to fix compared to SQLLogicTests. These are tests we discovered during development that emphasize blind spots in SQLLogicTests. Additionally, these tests are unique and do not overlap in coverage (unlike SQLLogicTests).

Passing	Total	Percent Passing
42152	42347	99.54