Re-Opening #1076 because it had bit-rotted to a point of no return.
However it has improved. Now with Weak references and no incrementing Rc
strong counts.
This also includes a better test extension that returns info about the
other tables in the schema.

(theme doesn't show rows column)
Closes#1366
Fixes#1567
Probably also fixes#1485
Currently we are simply unable to read any WAL frames from disk once a
fresh process w/ Limbo is opened, since we never try to read anything
from disk unless we already have it in our in-memory frame cache.
This commit implements a crude way of reading entire WAL into memory as
a single buffer and reconstructing the frame cache.
Reviewed-by: Pere Diaz Bou <pere-altea@homail.com>
Closes#1570
Shared cache requires more locking mechasnisms. We still have multi
threading issues not related to shared cache so it is wise to first fix
those and then once they are fixed, we can incrementally add shared
cache back with locking in place.
Reviewed-by: Jussi Saurio <jussi.saurio@gmail.com>
Closes#1568
Added a benchmark to bench TPC-H with criterion and have it uploaded to
Nyrkio. I did not delete the other tpc-h job because maybe someone uses
it and I'm not aware of it.
Closes#1560
Currently we are simply unable to read any WAL frames from disk
once a fresh process w/ Limbo is opened, since we never try to read
anything from disk unless we already have it in our in-memory
frame cache.
This commit implements a crude way of reading entire WAL into memory
as a single buffer and reconstructing the frame cache.
Adds support for `UNION ALL` and introduces `Plan::CompoundSelect` so
that it can be extended to support `UNION/EXCEPT/INTERSECT` as well
```sql
do_execsql_test_on_specific_db {:memory:} select-union-all-1 {
CREATE TABLE t1(x INTEGER);
CREATE TABLE t2(x INTEGER);
CREATE TABLE t3(x INTEGER);
INSERT INTO t1 VALUES(1),(2),(3);
INSERT INTO t2 VALUES(4),(5),(6);
INSERT INTO t3 VALUES(7),(8),(9);
SELECT x FROM t1
UNION ALL
SELECT x FROM t2
UNION ALL
SELECT x FROM t3;
} {1
2
3
4
5
6
7
8
9}
do_execsql_test_on_specific_db {:memory:} select-union-all-with-filters {
CREATE TABLE t4(x INTEGER);
CREATE TABLE t5(x INTEGER);
CREATE TABLE t6(x INTEGER);
INSERT INTO t4 VALUES(1),(2),(3),(4);
INSERT INTO t5 VALUES(5),(6),(7),(8);
INSERT INTO t6 VALUES(9),(10),(11),(12);
SELECT x FROM t4 WHERE x > 2
UNION ALL
SELECT x FROM t5 WHERE x < 7
UNION ALL
SELECT x FROM t6 WHERE x = 10;
} {3
4
5
6
10}
```
Supports LIMIT. Currently does not support `WITH()`, `OFFSET` or `ORDER
BY` and explicitly returns a parse error if those are present.
Closes#1541