Tomas Vondra 6ca015f9f0 Track unowned relations in doubly-linked list ... Relations dropped in a single transaction are tracked in a list of unowned relations. With large number of dropped relations this resulted in poor performance at the end of a transaction, when the relations are removed from the singly linked list one by one. Commit b4166911 attempted to address this issue (particularly when it happens during recovery) by removing the relations in a reverse order, resulting in O(1) lookups in the list of unowned relations. This did not work reliably, though, and it was possible to trigger the O(N^2) behavior in various ways. Instead of trying to remove the relations in a specific order with respect to the linked list, which seems rather fragile, switch to a regular doubly linked. That allows us to remove relations cheaply no matter where in the list they are. As b4166911 was a bugfix, backpatched to all supported versions, do the same thing here. Reviewed-by: Alvaro Herrera Discussion: https://www.postgresql.org/message-id/flat/80c27103-99e4-1d0c-642c-d9f3b94aaa0a%402ndquadrant.com Backpatch-through: 9.4		2019-03-27 02:39:39 +01:00
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buffer	Update copyright for 2019	2019-01-02 12:44:25 -05:00
file	Move hash_any prototype from access/hash.h to utils/hashutils.h	2019-03-11 13:17:50 -03:00
freespace	Improve code comments in b0eaa4c51b.	2019-03-16 06:55:56 +05:30
ipc	Add macro to cast away volatile without allowing changes to underlying type	2019-03-25 09:37:03 +01:00
large_object	Remove superfluous tqual.h includes.	2019-01-21 12:15:02 -08:00
lmgr	Enable parallel query with SERIALIZABLE isolation.	2019-03-15 17:47:04 +13:00
page	Track block level checksum failures in pg_stat_database	2019-03-09 10:47:30 -08:00
smgr	Track unowned relations in doubly-linked list	2019-03-27 02:39:39 +01:00
Makefile	Remove cvs keywords from all files.	2010-09-20 22:08:53 +02:00