73de50e13e
Presently, pg_upgrade obtains the number of subscriptions in the to-be-upgraded cluster by first querying pg_subscription in every database for the number of subscriptions in only that database. Then, in count_old_cluster_subscriptions(), it adds all the values collected in the first step. This is expensive, especially when there are many databases. Fortunately, there is a better way to retrieve the subscription count. Since pg_subscription is a shared catalog, we only need to connect to a single database and query it once. This commit modifies pg_upgrade to use that approach, which also allows us to trim several lines of code. In passing, move the call to get_db_subscription_count(), which has been renamed to get_subscription_count(), from get_db_rel_and_slot_infos() to the dedicated >= v17 section in check_and_dump_old_cluster(). We may be able to make similar improvements to get_old_cluster_logical_slot_infos(), but that is left as a future exercise. Reviewed-by: Michael Paquier, Amit Kapila Discussion: https://postgr.es/m/ZprQJv_TxccN3tkr%40nathan Backpatch-through: 17
PostgreSQL Database Management System
This directory contains the source code distribution of the PostgreSQL database management system.
PostgreSQL is an advanced object-relational database management system that supports an extended subset of the SQL standard, including transactions, foreign keys, subqueries, triggers, user-defined types and functions. This distribution also contains C language bindings.
Copyright and license information can be found in the file COPYRIGHT.
General documentation about this version of PostgreSQL can be found at https://www.postgresql.org/docs/17/. In particular, information about building PostgreSQL from the source code can be found at https://www.postgresql.org/docs/17/installation.html.
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