diff --git a/db/pglite/build/README.md b/db/pglite/build/README.md
index b096899b6..64333cbac 100644
--- a/db/pglite/build/README.md
+++ b/db/pglite/build/README.md
@@ -11,6 +11,9 @@ electric-sql/postgres-pglite, branch REL_17_5_WASM-pglite). Clone it to /tmp/pgl
 - `wasi-c.diff` — makes the forced `-fPIC` in the compiler wrapper overridable (`PGLITE_PIC`). NOTE: the matching
   `-fpic` in `postgresql-src/wasm-build/build-pgcore.sh` (cloned at build time) is not covered by a diff here; the
   `-fno-pic` experiment did not take effect and is unmeasured.
+- `message_context_reset.diff` — goes in `patches/pglite-wasm/`. The fork stubs `MemoryContextResetAndDeleteChildren`
+  (removed in PostgreSQL 17) as an empty macro, so `MessageContext` is never reset and every wire message leaks its
+  parse/plan state (~10 KB per statement; a library scan reached 15 GB). The patch maps it to `MemoryContextReset`.
 - `clear_error_portals.diff` — goes in `patches/pglite-wasm/`. A PostgreSQL ERROR traps the wasm instance, which skips
   every PG_CATCH, so the active portal is never marked failed and the next statement fails with
   "cannot drop active portal". Wrapping `AbortCurrentTransaction()` in `clear_error()` with
diff --git a/db/pglite/build/message_context_reset.diff b/db/pglite/build/message_context_reset.diff
new file mode 100644
index 000000000..d8e5a7fe8
--- /dev/null
+++ b/db/pglite/build/message_context_reset.diff
@@ -0,0 +1,12 @@
+--- a/pg_main.c
++++ b/pg_main.c
+@@ -28,7 +28,8 @@
+ 
+ // globals
+ 
+-#define MemoryContextResetAndDeleteChildren(...)
++// PG17 dropped this macro; the no-op stub leaked every message's parse/plan state.
++#define MemoryContextResetAndDeleteChildren(ctx) MemoryContextReset(ctx)
+ // #define SpinLockInit(...)
+ 
+ 
diff --git a/db/pglite/pglite.go b/db/pglite/pglite.go
index 46a5a35c5..a329e5fa3 100644
--- a/db/pglite/pglite.go
+++ b/db/pglite/pglite.go
@@ -403,6 +403,9 @@ func (pg *PGlite) startBridge() error {
 // DataDir is the host directory holding the cluster.
 func (pg *PGlite) DataDir() string { return pg.dataDir }
 
+// MemorySize reports the wasm linear memory size in bytes; it only ever grows.
+func (pg *PGlite) MemorySize() uint64 { return uint64(pg.mod.Memory().Size()) }
+
 // Connections reports how many client connections the bridge has accepted.
 func (pg *PGlite) Connections() int64 { return pg.connections.Load() }
 
diff --git a/db/pglite/pglite.wasi.gz b/db/pglite/pglite.wasi.gz
index b406c1504..ce1f6c6a8 100644
Binary files a/db/pglite/pglite.wasi.gz and b/db/pglite/pglite.wasi.gz differ