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From: Zsolt Parragi <zsolt.parragi@percona.com>
Date: Wed, 18 Mar 2026 20:49:37 +0000
Message-ID: 
 <CAN4CZFMk10YCixVTnt+uBaUH_BH1R=Er-PnPs2YDBhFjuE3K-Q@mail.gmail.com>
Subject: Re: Stack-based tracking of per-node WAL/buffer usage
To: Lukas Fittl <lukas@fittl.com>
Cc: Tomas Vondra <tomas@vondra.me>,
	PostgreSQL Hackers <pgsql-hackers@lists.postgresql.org>,
 Andres Freund <andres@anarazel.de>,
	Peter Smith <smithpb2250@gmail.com>
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Archived-At: 
 <https://www.postgresql.org/message-id/CAN4CZFMk10YCixVTnt%2BuBaUH_BH1R%3DEr-PnPs2YDBhFjuE3K-Q%40mail.gmail.com>
Precedence: bulk

+ instr_stack.stack_space *= 2;
+ instr_stack.entries = repalloc_array(instr_stack.entries,
Instrumentation *, instr_stack.stack_space);

Can't this also cause issues with OOM? repalloc_array failing, but we
already doubled stack_space.
The initialization above uses the same order, but that should be safe
as entries is initially NULL.


+ * 2) Accumulate all instrumentation to the currently active instrumentation,
+ *    so that callers get a complete picture of activity, even after an abort
...
+ if (idx >= 0)
+ {
+ while (instr_stack.stack_size > idx + 1)
+ instr_stack.stack_size--;
+
+ InstrPopStack(instr);
+ }

There seems to be one more bug in this:

1. EXPLAIN ANALYZE fires a trigger
2. The trigger function throws ERROR, InstrStopTrigger never runs
3. ResOwnerReleaseInstrumentation runs but only checks
unfinalized_children, not triggers
4. InstrStopFinalize discards the trigger entry
5. Trigger instrumentation information shows 0