Add support for QuestDB

[mrigger]

See questdb/questdb#595.

[MingCheng991129]

I ran the code of QuestDB and found that the correctness rate (successful statements) of generated queries are very low (around 5%).
[2023/01/29 00:35:33] Executed 9 queries (1 queries/s; 0.40/s dbs, successful statements: 4%). Threads shut down: 1.
The running command I use: java -jar sqlancer-*.jar --num-threads 4 questdb
Is it actually an issue?

[mrigger]

I think it would be useful to analyze which statements are failing. The rate definitely seems low. @SuriZhang, do you have any idea?

[SuriZhang]

Not sure why this happens. But iirc, maybe this shouldn’t be run using multiple threads(at least I didn’t do that)? I can have a quick check later.  可用于iOS的myMail发送 2023年1月29日 星期日 +0800 下午1:53 发件人 ***@***.*** ***@***.***>:

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I think it would be useful to analyze which statements are failing. The rate definitely seems low. @SuriZhang , do you have any idea? — Reply to this email directly, view it on GitHub , or unsubscribe . You are receiving this because you were mentioned. Message ID: <sqlancer/sqlancer/issues/457/1407569950 @ github . com>

[mrigger]

@MingCheng991129 discovered that the number of tables referenced in queries is very high, so that might be the issue.

[SuriZhang]

@MingCheng991129 pls see #712 . this might give you some ideas on the limitation of the current (and very preliminary) version of support of questDB in sqlancer.
I talked with Manuel offline, we believe the tables might not be the cause. also we checked the queries generated are syntax-correct.