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QuestDB is supported by SQLancer — the main repository ships a testing implementation for it. SQLancer is credited with 55 bugs in it, reported between 2022-10-26 and 2026-02-09. Its source is at questdb/questdb.

How the bugs break down

By year reported

2022
3
2023
44
2024
6
2026
2

Who found them

Found by the SQLancer project
53
Found by someone outside the project
2

By status

Fixed
49
Confirmed
1
Open
5

By symptom

Unclassified
55

By technique

Technique not recorded
55

Why each bug counts

Filed by someone who runs SQLancer campaigns
49
The reproducer carries SQLancer's generated schema
4
The report names SQLancer
2

Who reported them (5)

YuanchengJiang
49
Ming Wei Tan
2
puzpuzpuz
2
SuriZhang
1
suyZhong
1

Every bug on record (55)

One row per report, newest first, each linking to the report itself. Rejected reports are marked and are not part of any count above.

Reported Report Status Technique Reporter
2026-02-09 AssertionError: index 1 out of bounds for list size 1 fixed — YuanchengJiang
2026-02-09 AssertionError at FilteredRecordCursorFactory.java fixed — YuanchengJiang
2024-09-25 Internal error thrown in select query fixed — Ming Wei Tan
2024-09-18 NULL record not retrieved if NULL is in WHERE clause verified — Ming Wei Tan
2024-05-21 Incorrect result with window function and table joins open — YuanchengJiang
2024-05-21 Incorrect result when having NULL within the CASE...WHEN clause open — YuanchengJiang
2024-05-15 Incorrect result when having null in case clause fixed — YuanchengJiang
2024-05-13 Incorrect result when having NULL with IN operation fixed — YuanchengJiang
2023-12-11 Unexpected results when comparing NULL value in WHERE clause open — suyZhong
2023-11-28 Incorrect results with nested joins fixed — YuanchengJiang
2023-11-13 NullPointerException: Cannot read field "token" because "first" is null fixed — YuanchengJiang
2023-11-09 Unexpected results when having brackets with window query fixed — YuanchengJiang
2023-11-09 Unexpected invalid column not completely fixed fixed — YuanchengJiang
2023-11-09 Unexpected DatabaseError: queries have different number of columns in window function with union fixed — YuanchengJiang
2023-11-09 NullPointerException: Cannot invoke "io.questdb.cairo.sql.SymbolTable.valueOf(int)" because "this.symbolTab... fixed — YuanchengJiang
2023-11-09 Incorrect result with window function fixed — YuanchengJiang
2023-11-09 Inaccurate result with sum float data open — YuanchengJiang
2023-10-10 ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 16 fixed — YuanchengJiang
2023-10-09 Incorrect results with symbol comparison fixed — YuanchengJiang
2023-09-12 Invalid column error not completely fixed fixed — YuanchengJiang
2023-08-19 Invalid column error with LEFT OUTER JOIN fixed — YuanchengJiang
2023-08-19 Incorrect results returned from `UNION` fixed — YuanchengJiang
2023-08-07 UnsupportedOperationException in IntFunction.getStr(IntFunction.java:145) fixed — YuanchengJiang
2023-08-07 StringIndexOutOfBoundsException: String index out of range: 0 with ORDER BY empty string fixed — YuanchengJiang
2023-08-04 Invalid Column error with multiple JOIN fixed — YuanchengJiang
2023-07-25 Unexpected Error Invalid Column with multiple JOIN fixed — YuanchengJiang
2023-07-21 ClassCastException: GenericRecordMetadata cannot be cast to JoinRecordMetadata in generateJoins() fixed — YuanchengJiang
2023-07-19 Incorrect result returned by `INTERSECT` fixed — YuanchengJiang
2023-07-19 Inaccurate results with `EXCEPT`/`INTERSECT` fixed — YuanchengJiang
2023-07-18 Unrobust comparison between string and char fixed — YuanchengJiang
2023-07-18 Suspicious incorrect result when left join with an empty table fixed — YuanchengJiang
2023-06-29 java.lang.NullPointerException: Cannot read field "type" because "op" is null in rewriteAggregate(SqlOptimi... fixed — YuanchengJiang
2023-06-10 StringIndexOutOfBoundsException: String index out of range: 0 fixed — YuanchengJiang
2023-06-10 NullPointerException: Cannot read field "type" because "column" is null fixed — YuanchengJiang
2023-06-10 CairoException when casting string to timestamp fixed — YuanchengJiang
2023-06-10 ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 0 at io.questdb.std.LongList.extendAndSet fixed — YuanchengJiang
2023-06-08 ImplicitCastException and stuck when comparing `STRING` with `NULL` fixed — YuanchengJiang
2023-06-08 ClassCastException: NullConstant cannot be cast to class SymbolFunction fixed — YuanchengJiang
2023-06-05 NullPointerException Cannot invoke ".isUndefined()" because the return value of ".getQuick(int)" is null fixed — YuanchengJiang
2023-06-01 ArrayIndexOutOfBoundsException: Index -1 out of bounds for length 16 fixed — YuanchengJiang
2023-05-29 Unexpected StringIndexOutOfBoundsException with empty string fixed — YuanchengJiang
2023-05-29 NullPointerException: Cannot read field "type" because "node" is null with constant expression fixed — YuanchengJiang
2023-05-29 NullPointerException Cannot invoke ".getAst()" because "queryColumn" is null with `order by` clause fixed — YuanchengJiang
2023-05-23 Unexpected UnsupportedOperationException with `join` query on non-boolean expression fixed — YuanchengJiang
2023-05-22 Consuming input failed: server closed the connection unexpectedly fixed — YuanchengJiang
2023-05-17 `Null` in equality operator fixed — YuanchengJiang
2023-05-17 Unexpected NullPointerException with `null` query fixed — YuanchengJiang
2023-05-17 Unexpected ClassCastException with `null` query fixed — YuanchengJiang
2023-05-11 Unexpected Internal Error: UnsupportedOperationException fixed — YuanchengJiang
2023-05-11 Unexpected Internal Error: NullPointerException fixed — YuanchengJiang
2023-05-11 Unexpected Internal Error: Index -1 out of bounds for length 16 fixed — YuanchengJiang
2023-05-10 Unexpected error when using `count()` fixed — YuanchengJiang
2022-11-03 Unexpected result set with a no-op numeric filter fixed — puzpuzpuz
2022-11-03 SQL engine issues found by SQLancer open — puzpuzpuz
2022-10-26 CREATE TABLE with INDEX causing error fixed — SuriZhang

Every figure on this page is computed from _data/impact/. The attribution policy explains what has to be true for a bug to be counted.