Current chDB(till v2.0.2) relys on temp disk storage to keep the session data.
Everytime session.query runs almost everything in memory will be recreated and reinit which caused a lot of state problems like:
Originally posted by **l1t1** February 7, 2024
```sql
:) create table a engine=Memory as select 1 a;
0.11995077133178711
:) select * from a;
Code: 60. DB::Exception: Table _local.a does not exist. (UNKNOWN_TABLE)
0.11473512649536133
```
Here is how clickhouse-local interactive mode works:
```
root@0a8b55995b6e:/auxten/chdb/tests# ./ch24.5/usr/bin/clickhouse
ClickHouse local version 24.5.1.1763 (official build).
0a8b55995b6e :) create table a engine=Memory as select 1 a;
CREATE TABLE a
ENGINE = Memory
AS SELECT 1 AS a
Query id: 967a5d72-bb39-4a42-8a11-a108eda2a5d9
Ok.
0 rows in set. Elapsed: 0.008 sec.
0a8b55995b6e :) select * from a;
SELECT *
FROM a
Query id: e5be6b9b-b752-4418-8753-adb8cc69a127
┌─a─┐
1. │ 1 │
└───┘
1 row in set. Elapsed: 0.008 sec.
```
The good part are:
Better support for states like 'Memory Table Engine', 'UDF', 'SET', 'USE'
Less tricky code to handle default database and 'SET', 'USE' statements
Without load tables and do init on every query function call, Performance should be much better than current implementation
Current chDB(till v2.0.2) relys on temp disk storage to keep the session data. Everytime
session.query
runs almost everything in memory will be recreated and reinit which caused a lot of state problems like:Also some feature implemented and bugs walked around before also need a better way to fix:
133
176
207
Some chDB contributor also gave a try to make session better:
The good part are:
query
function call, Performance should be much better than current implementation