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Embeddable, replicated and fault-tolerant SQL engine.
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Recursion in EXEC_SQL request handling #701

Closed cole-miller closed 1 month ago

cole-miller commented 2 months ago

Copying the description from #697

Recall that the issue arises with a call stack like this (callees at the top)

handle_exec_sql_next handle_exec_sql_cb leaderExecV2 leaderbarrier leaderexec handle_exec_sql_next ...

that is, indirect recursion that can generate a number of stack frames proportional to the number of ;-separated statements in an EXEC_SQL request. This happens because leaderbarrier and leaderexec can invoke their callbacks synchronously when suspending is not required (respectively, because the FSM is up to date with the raft log and and because sqlite3_step generated no changed pages).