Description:
When using a LATERAL subquery that references an outer query block and employs Index Skip Scan optimization, the server crashes with an assertion failure in `handler::ha_index_init()`:
```
mysqld: /data/mysql-server/sql/handler.cc:2792: int handler::ha_index_init(uint, bool): Assertion `inited == NONE' failed.
```
## Root Cause
In `IndexSkipScanIterator::Init()` (line 152), the code calls `ha_index_init()` without first checking if the handler is already initialized. When a LATERAL subquery is re-materialized for each outer row, `IndexSkipScanIterator::Init()` is called multiple times, but the handler's `inited` flag is still set from the previous iteration.
**Problematic Code (`sql/range_optimizer/index_skip_scan.cc:152`):**
```cpp
bool IndexSkipScanIterator::Init(void) {
// ... initialization code ...
// BUG: No check for table()->file->inited before calling ha_index_init()
if ((result = table()->file->ha_index_init(index, true))) {
table()->file->print_error(result, MYF(0));
return true;
}
// ...
}
```
## Stack Trace
```
#0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50
#1 __GI_abort () at abort.c:79
#2 __assert_fail_base (...) at assert.c:92
#3 __GI___assert_fail (...) at assert.c:101
#4 handler::ha_index_init(unsigned int, bool) at sql/handler.cc:2792
#5 IndexSkipScanIterator::Init() at sql/range_optimizer/index_skip_scan.cc:152
#6 FilterIterator::Init() at sql/iterators/composite_iterators.cc:...
#7 LimitOffsetIterator::Init() at sql/iterators/composite_iterators.cc:...
#8 MaterializeIterator::MaterializeQueryBlock(...) at sql/iterators/composite_iterators.cc:846
#9 MaterializeIterator::Init() at sql/iterators/composite_iterators.cc:557
#10 NestedLoopIterator::Read() at sql/iterators/composite_iterators.cc:...
...
```
How to repeat:
CREATE TABLE t_outer (id INT PRIMARY KEY);
INSERT INTO t_outer VALUES (1), (2);
-- trigger Bug
SET SESSION optimizer_switch = 'hash_join=off';
SELECT subq_0.id as c0
FROM (SELECT id FROM t_outer LIMIT 110) as subq_0,
LATERAL (
SELECT subq_0.id as c1
FROM information_schema.ST_SPATIAL_REFERENCE_SYSTEMS as ref_8
WHERE ref_8.ORGANIZATION IS NOT NULL
LIMIT 64
) as subq_1;
© 2026, Oracle Corporation and/or its affiliates
Description: When using a LATERAL subquery that references an outer query block and employs Index Skip Scan optimization, the server crashes with an assertion failure in `handler::ha_index_init()`: ``` mysqld: /data/mysql-server/sql/handler.cc:2792: int handler::ha_index_init(uint, bool): Assertion `inited == NONE' failed. ``` ## Root Cause In `IndexSkipScanIterator::Init()` (line 152), the code calls `ha_index_init()` without first checking if the handler is already initialized. When a LATERAL subquery is re-materialized for each outer row, `IndexSkipScanIterator::Init()` is called multiple times, but the handler's `inited` flag is still set from the previous iteration. **Problematic Code (`sql/range_optimizer/index_skip_scan.cc:152`):** ```cpp bool IndexSkipScanIterator::Init(void) { // ... initialization code ... // BUG: No check for table()->file->inited before calling ha_index_init() if ((result = table()->file->ha_index_init(index, true))) { table()->file->print_error(result, MYF(0)); return true; } // ... } ``` ## Stack Trace ``` #0 __GI_raise (sig=sig@entry=6) at ../sysdeps/unix/sysv/linux/raise.c:50 #1 __GI_abort () at abort.c:79 #2 __assert_fail_base (...) at assert.c:92 #3 __GI___assert_fail (...) at assert.c:101 #4 handler::ha_index_init(unsigned int, bool) at sql/handler.cc:2792 #5 IndexSkipScanIterator::Init() at sql/range_optimizer/index_skip_scan.cc:152 #6 FilterIterator::Init() at sql/iterators/composite_iterators.cc:... #7 LimitOffsetIterator::Init() at sql/iterators/composite_iterators.cc:... #8 MaterializeIterator::MaterializeQueryBlock(...) at sql/iterators/composite_iterators.cc:846 #9 MaterializeIterator::Init() at sql/iterators/composite_iterators.cc:557 #10 NestedLoopIterator::Read() at sql/iterators/composite_iterators.cc:... ... ``` How to repeat: CREATE TABLE t_outer (id INT PRIMARY KEY); INSERT INTO t_outer VALUES (1), (2); -- trigger Bug SET SESSION optimizer_switch = 'hash_join=off'; SELECT subq_0.id as c0 FROM (SELECT id FROM t_outer LIMIT 110) as subq_0, LATERAL ( SELECT subq_0.id as c1 FROM information_schema.ST_SPATIAL_REFERENCE_SYSTEMS as ref_8 WHERE ref_8.ORGANIZATION IS NOT NULL LIMIT 64 ) as subq_1;