fix(electric): Fix temporary replication slot going over character li…

…mit (#1315)

Addresses [this
issue](https://linear.app/electric-sql/issue/VAX-1888/temporary-replication-slot-name-too-long-crashes-electric)

This is a quick fix to avoid failures because of long names but the
longer term solution is to ensure the replication slot names are smaller
in general, see issue description for suggestions.

.changeset/yellow-geckos-mix.md

@@ -0,0 +1,5 @@
+---
+"@core/electric": patch
+---
+
+Truncate temporary replication slot name to always fit within Postgres' limit of 63 chars

components/electric/lib/electric/replication/postgres/logical_replication_producer.ex

@@ -111,7 +111,8 @@ defmodule Electric.Replication.Postgres.LogicalReplicationProducer do
 
     publication = repl_opts.publication
     main_slot = repl_opts.slot
-    tmp_slot = main_slot <> "_rc"
+    # Ensure temporary slot name fits within Postgres' limit of 63 chars
+    tmp_slot = String.slice(main_slot, 0..59) <> "_rc"
 
     Logger.metadata(pg_producer: origin)