Re: Listen / Notify - what to do when the queue is full

Joachim Wieland wrote:

> + typedef struct AsyncQueueEntry
> + {
> + /*
> + * this record has the maximal length, but usually we limit it to
> + * AsyncQueueEntryEmptySize + strlen(payload).
> + */
> + Size length;
> + Oid dboid;
> + TransactionId xid;
> + int32 srcPid;
> + char channel[NAMEDATALEN];
> + char payload[NOTIFY_PAYLOAD_MAX_LENGTH];
> + } AsyncQueueEntry;
> + #define AsyncQueueEntryEmptySize \
> + (sizeof(AsyncQueueEntry) - NOTIFY_PAYLOAD_MAX_LENGTH + 1)

These are the on-disk notifications, right? It seems to me a bit
wasteful to store channel name always as NAMEDATALEN bytes. Can we
truncate it at its strlen? I realize that this would cause the struct
definition to be uglier (you will no longer be able to have both channel
and payload pointers, only a char[1] pointer to a data area to which you
write both). Typical channel names should be short, so IMHO this is
worthwhile. Besides, I think the uglification of code this causes
should be fairly contained ...

--
Alvaro Herrera http://www.CommandPrompt.com/
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