Trackback has MySQL-specific REPLACE INTO

I wrote first entry with four TrackBack pings on a post-4.5.2 Drupal system today, and got some very odd results. Most noticeably, after previewing and submitting, I was sent back to the editing page, as if I had gone through another round of previews, rather than actually submitting. I checked the front page, and the entry actually did show up normally, but as time went by, I realized that the pings had not been sent; no trackback entries showed up at any of the other locations. I actually had cause to edit the document some time later, and decided to try again to insert the trackback entry. Again, after clicking Submit, I was returned to the editing page, the edits having been made, but no trackbacks having been sent.

Trying to find out if my whole system was broken, I tried creating a few test entries with no TrackBack entries at all, and they worked just fine.

Poking through the TrackBack module code, I did spot some incompatible SQL, most notably use of the MySQL-specific REPLACE INTO command, while I'm using PostgreSQL as a backend. That has always been there, however, and I *have* successfully sent some BackTrack entries in the past, though generally to a single source. Once, some time ago, I sent two at once, and they both seemed to go through (though the software on the other side of one of them really didn't like that I have my base URL set with https instead of http).

No entries are stored in the trackback_sent table, but that, too, has always been true, even for successful publications.

No messages are left in either the Drupal logs or the PostgreSQL logs.