在 Apache Ignite 中删除并重新创建表

Question

I am having a problem when I want to DROP a table and recreate it in APACHE IGNITE; I am using a combination of REST API and PyIgnite to perform the operations. IGNITE says the table do not exists, however it does not let me recreate it saying that it exists

>>> DROP_QUERY_ALERT="DROP TABLE alerts"
>>> client.sql(DROP_QUERY_ALERT)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.7/site-packages/pyignite/client.py", line 404, in sql
    raise SQLError(result.message)
pyignite.exceptions.SQLError: Table doesn't exist: ALERTS
>>> CREATE_ALERT_QUERY = '''CREATE TABLE storage.alerts (
...         id VARCHAR PRIMARY KEY,
...         name VARCHAR,
...         address_field VARCHAR,
...         create_on TIMESTAMP,
...         integration VARCHAR,
...         alert VARCHAR,
...     ) WITH "CACHE_NAME=storage"'''
>>> client.sql(CREATE_ALERT_QUERY)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.7/site-packages/pyignite/client.py", line 404, in sql
    raise SQLError(result.message)
pyignite.exceptions.SQLError: Table already exists: ALERTS
>>> 

If I try to make a query, it also fails:

>>> N_ALERT_QUERY = '''SELECT * FROM alerts'''
>>> result = client.sql(N_ALERT_QUERY, include_field_names=True)
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
  File "/usr/local/lib/python3.7/site-packages/pyignite/client.py", line 404, in sql
    raise SQLError(result.message)
pyignite.exceptions.SQLError: Failed to parse query. Table "ALERTS" not found; SQL statement:
SELECT * FROM alerts [42102-197]
>>> 

I am lost since this seemed to work before, but now I am unable to continue. Is this a bug, a known behavior? Am I missing something?

Thank you.

Answer 1

It may be a known behavior :

Note, however, that the cache we create can not be dropped with DDL command. … It should be deleted as any other key-value cache.

Answer 2

After some search and trying, I finally found that there was indeed a table by executing the following query:

SHOW_TABLES_QUERY="SELECT * FROM INFORMATION_SCHEMA.TABLES"

It turns out that IGNITE do not drop a table if it has at least a records, as it was in this case ( http://apache-ignite-users.70518.x6.nabble.com/Table-not-getting-dropped-td27957.html ).

I deleted the records, and dropped the table. It took some minutes, but then I was able to recreate the table.

Some of the confusion in my case was related to the fact that TABLE_NAME should have been replaced with <cachename>.TABLE_NAME when performing the drop query:

DROP_QUERY_ALERT="DROP TABLE storage.alerts"