diff options
| -rw-r--r-- | src/backend/utils/resowner/README | 15 |
1 files changed, 7 insertions, 8 deletions
diff --git a/src/backend/utils/resowner/README b/src/backend/utils/resowner/README index 2998f6bb362..f94c9700df4 100644 --- a/src/backend/utils/resowner/README +++ b/src/backend/utils/resowner/README @@ -54,20 +54,19 @@ The basic operations on a ResourceOwner are: * delete a ResourceOwner (including child owner objects); all resources must have been released beforehand +This API directly supports the resource types listed in the definition of +ResourceOwnerData struct in src/backend/utils/resowner/resowner.c. +Other objects can be associated with a ResourceOwner by recording the address +of the owning ResourceOwner in such an object. There is an API for other +modules to get control during ResourceOwner release, so that they can scan +their own data structures to find the objects that need to be deleted. + Locks are handled specially because in non-error situations a lock should be held until end of transaction, even if it was originally taken by a subtransaction or portal. Therefore, the "release" operation on a child ResourceOwner transfers lock ownership to the parent instead of actually releasing the lock, if isCommit is true. -Currently, ResourceOwners contain direct support for recording ownership of -buffer pins, lmgr locks, and catcache, relcache, plancache, tupdesc, and -snapshot references. Other objects can be associated with a ResourceOwner by -recording the address of the owning ResourceOwner in such an object. There is -an API for other modules to get control during ResourceOwner release, so that -they can scan their own data structures to find the objects that need to be -deleted. - Whenever we are inside a transaction, the global variable CurrentResourceOwner shows which resource owner should be assigned ownership of acquired resources. Note however that CurrentResourceOwner |