RE: Skipping logical replication transactions on subscriber side - Mailing list pgsql-hackers

On Mon, Oct 18, 2021 9:34 AM Masahiko Sawada <sawada.mshk@gmail.com> wrote:
> I've attached updated patches that incorporate all comments I got so far.

Hi,

Here are some minor comments for the patches.

v17-0001-Add-a-subscription-errors-statistics-view-pg_sta.patch

1)

+    /* Clean up */
+    if (not_ready_rels != NIL)
+        list_free_deep(not_ready_rels);

Maybe we don't need the ' if (not_ready_rels != NIL)' check as
list_free_deep will do this check internally.

2)

+    for (int i = 0; i < msg->m_nentries; i++)
+    {
+        HASH_SEQ_STATUS sstat;
+        PgStat_StatSubWorkerEntry *wentry;
+
+        /* Remove all worker statistics of the subscription */
+        hash_seq_init(&sstat, subWorkerStatHash);
+        while ((wentry = (PgStat_StatSubWorkerEntry *) hash_seq_search(&sstat)) != NULL)
+        {
+            if (wentry->key.subid == msg->m_subids[i])
+                (void) hash_search(subWorkerStatHash, (void *) &(wentry->key),
+                                   HASH_REMOVE, NULL);

Would it be a little faster if we scan hashtable in outerloop and
scan the msg in innerloop ?
Like:
while ((wentry = (PgStat_StatSubWorkerEntry *) hash_seq_search(&sstat)) != NULL)
{
    for (int i = 0; i < msg->m_nentries; i++)
    ...


v17-0002-Add-RESET-command-to-ALTER-SUBSCRIPTION-command

1)
I noticed that we cannot RESET slot_name while we can SET it.
And the slot_name have a default behavior that " use the name of the subscription for the slot name.".
So, is it possible to support RESET it ?

Best regards,
Hou zj