Hello,
On 27.02.2016 03:05, Andres Freund wrote:
Hi,
I'm not really convinced by RegisterStandbyMsgPrefix() et al. There's
not much documentation about what it actually is supposed to
acomplish. Afaics you're basically forced to use
shared_preload_libraries with it right now? Also, iterating through a
linked list everytime something is logged doesn't seem very satisfying?
I have did some tests with a simple plugin. I have used event triggers
to send messages. It works, but I agree with Andres. We have problems if
plugin is not loaded. For example, if you will execute the query:
SELECT 'msg2' FROM pg_logical_send_message(false, 'test', 'msg2');
you will get the error (if plugin which should register a prefix is not
loaded yet):
ERROR: standby message prefix "test" is not registered
Some stylistic note (logical.c):
+static void message_cb_wrapper(ReorderBuffer *cache, ReorderBufferTXN *txn,
+ XLogRecPtr
message_lsn,
+ bool transactional,
const char *prefix,
+ Size sz, const char
*message)
+{
+ LogicalDecodingContext *ctx = cache->private_data;
+ LogicalErrorCallbackState state;
+ ErrorContextCallback errcallback;
It should be written in the following way:
static void
message_cb_wrapper(ReorderBuffer *cache, ReorderBufferTXN *txn,
XLogRecPtr message_lsn,
bool transactional, const char *prefix,
Size sz, const char *message)
{
LogicalDecodingContext *ctx = cache->private_data;
LogicalErrorCallbackState state;
ErrorContextCallback errcallback;
--
Artur Zakirov
Postgres Professional: http://www.postgrespro.com
Russian Postgres Company
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