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pgsql: pg_upgrade: Retrieve subscription count more efficiently. 2+ messages / 1 participants [nested] [flat]
* pgsql: pg_upgrade: Retrieve subscription count more efficiently. @ 2024-07-24 16:31 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 2+ messages in thread From: Nathan Bossart @ 2024-07-24 16:31 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org pg_upgrade: Retrieve subscription count more efficiently. 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 Branch ------ master Details ------- https://git.postgresql.org/pg/commitdiff/364509a2e7f92785407348ec702e39729fda6cf8 Modified Files -------------- src/bin/pg_upgrade/check.c | 13 +++++------ src/bin/pg_upgrade/info.c | 51 ++++++----------------------------------- src/bin/pg_upgrade/pg_upgrade.h | 4 ++-- 3 files changed, 15 insertions(+), 53 deletions(-) ^ permalink raw reply [nested|flat] 2+ messages in thread
* pgsql: pg_upgrade: Retrieve subscription count more efficiently. @ 2024-07-24 16:31 Nathan Bossart <nathan@postgresql.org> 0 siblings, 0 replies; 2+ messages in thread From: Nathan Bossart @ 2024-07-24 16:31 UTC (permalink / raw) To: pgsql-committers@lists.postgresql.org pg_upgrade: Retrieve subscription count more efficiently. 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 Branch ------ REL_17_STABLE Details ------- https://git.postgresql.org/pg/commitdiff/73de50e13e397da8e98ed59b0fe63a00051a7128 Modified Files -------------- src/bin/pg_upgrade/check.c | 13 +++++------ src/bin/pg_upgrade/info.c | 51 ++++++----------------------------------- src/bin/pg_upgrade/pg_upgrade.h | 4 ++-- 3 files changed, 15 insertions(+), 53 deletions(-) ^ permalink raw reply [nested|flat] 2+ messages in thread
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