Title
#users-public
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Suri Zhang

10/26/2022, 2:42 AM
hi there im working on adding questdb to sqlancer https://github.com/questdb/questdb/issues/595 but im also new to questdb. i have a couple questions (maybe super dumb tho :face_holding_back_tears: ) • is there a way to batch drop all tables created (i.e reset db to a clean state)?
--Caused by: org.postgresql.util.PSQLException: ERROR: cannot create index for [column='c0, type=BOOLEAN, path=/usr/local/var/questdb/db/t2][errno=-1]
--  Position: 13
• i have found this error ^^ by my initial runs with queries . i cant seem to find any more detailed info about this errorno. is this a bug or some intended constraints?
Andrey Pechkurov

Andrey Pechkurov

10/26/2022, 6:01 AM
Hi Suri
6:01 AM
QuestDB doesn't support indexes on non-symbol columns
6:01 AM
And it seems that sqlancer is trying to create one
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Suri Zhang

10/26/2022, 6:02 AM
ooh yes gotcha
Andrey Pechkurov

Andrey Pechkurov

10/26/2022, 6:02 AM
You'd need to modify sqlancer's Postgres test suite to create a QuestDB one. That's because we're not 100% Postgres compatible
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Suri Zhang

10/26/2022, 6:03 AM
im creating a new one for questdb
6:03 AM
but connected via postgres jdbc driver
6:04 AM
does
ERROR: Could not lock 'test' [reason='createTable']
means too frequent operations on one single table?
6:04 AM
drop then create with index
6:04 AM
sometimes i get these errors sometimes i dont
6:05 AM
also for q1 - is there a simpler way to clean the db? im manually executing the
DROP TABLEs
now
Andrey Pechkurov

Andrey Pechkurov

10/26/2022, 6:24 AM
does ERROR: Could not lock 'test' [reason='createTable'] means too frequent operations on one single table?
It means that CREATE TABLE AS is still writing into the table while you're trying to run another write operation
6:24 AM
QuestDB has single writer design: concurrent writes over PGWire are not supported and you'd get such error messages
6:25 AM
We have a troubleshooting guide with common problems
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Suri Zhang

10/26/2022, 6:26 AM
gr8 thanks!!!