Re: [I] Cannot drop and create a table in a single statement using ``. [shardingsphere]

["terrymanu (via GitHub)" <gi...@apache.org>]

terrymanu commented on issue #35093:
URL: https://github.com/apache/shardingsphere/issues/35093#issuecomment-3671295708

   ##  Issue Understanding
   
     - In shardingsphere-proxy 5.5.2 (PostgreSQL protocol, backend PostgreSQL 17.2), sending DROP TABLE ...; CREATE TABLE ...; in a single PQexec fails with a syntax error, while splitting into two PQexec calls or connecting directly to PostgreSQL works. You want the official documentation reference that states multi-statement execution is not supported.
   
   ##  Root Cause
   
     - The Proxy’s PostgreSQL frontend treats Simple Query (PQexec default) as a single SQL. It does not implement semicolon splitting or multi-statement execution, so the combined string is parsed as one statement and fails. The trailing “, null” is from the Proxy error message template appending an empty reason string.
   
   ##  Analysis
   
     - The official English documentation explicitly lists this limitation:
         - docs/document/content/features/sharding/limitation.en.md, section “Semicolons separate multiple statements”: “Not support simultaneous execution of multiple SQL statements separated by ;.”
     - DistSQL rule statements and table DDL are expected to be sent one by one to keep parsing, routing, and metadata broadcasting correct.
   
   ##  Conclusion
   
     - This is a known functional limitation, not a Proxy bug. Please keep DROP TABLE and CREATE TABLE as separate statements (multiple PQexec calls or client-side splitting).


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