Sami Imseih <[email protected]> 于2026年4月7日周二 06:56写道：
> Hi, > > While working on extending tests for dshash.c [1], I realized that a > user that creates a hash table with GetNamedDSHash() has no way > to cap the size of the dsa area underpinning the table by using > dsa_set_size_limit(). This is because the dsa_area created using > this API is not exposed to the user. > > This is a gap for users of the GetNamedDSHash() API, > because it's very likely that the callers don't want runaway growth of > these hash tables. > > Attached is a new API, dshash_get_dsa_area() that takes in a dshash_table > and returns the area. The caller can then use dsa_set_size_limit() to limit > the size. > > We could change the GetNamedDSHash() API to take in a size, but that > will not be ideal since a caller may want to change the size dynamically > after > the hash table is created. > > I don't have a patch for this yet, but I also think it will make sense for > pg_dsm_registry_allocations to also show the max_size > > postgres=# select * from pg_dsm_registry_allocations; > name | type | size > ------------------------+---------+--------- > test_dsm_registry_dsa | area | 1048576 > test_dsm_registry_hash | hash | 1048576 > test_dsm_registry_dsm | segment | 20 > (3 rows) > > Thoughts? > > > [1] [https://www.postgresql.org/message-id/acXCJODjsCytdpwT%40paquier.xyz] > > -- > Sami Imseih > Amazon Web Services (AWS) > Hi, I think an assert check could be added in this patch for better safety. Assert(hash_table != NULL); Best regards, -- wang jie
