Improve MemoryContext management to prevent memory exhaustion between queries

Author: Marcus Pousette

pglite-wasm/pg_main.c

@@ -28,7 +28,18 @@
 
 // globals
 
-#define MemoryContextResetAndDeleteChildren(...)
+/*
+ * Ensure MessageContext and its children are actually cleared between
+ * queries. Leaving this as a no-op causes unbounded growth in
+ * MessageContext when large query strings or parameters are processed,
+ * eventually exhausting memory.
+ */
+#undef MemoryContextResetAndDeleteChildren
+#define MemoryContextResetAndDeleteChildren(ctx) \
+    do {                                           \
+        MemoryContextDeleteChildren((ctx));         \
+        MemoryContextReset((ctx));                  \
+    } while (0)
 // #define SpinLockInit(...)