Pumice db #2
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Pumice db #2
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It was enabling, not disabling.
This is very high level and there are probably still lots of incorrect assumptions floating around.
More fleshing out of the read and write handlers including how KV pairs will be shared with the upper and lower layer (the lower layer is needed so that pending commit state may be tracked per-application object).
This patch mostly deals with the implementation of pmdb_object_lookup() and its supporting code. pmdb_object_lookup() starts to work with the rocksDB api to lookup the KV for a PMDB object. A PMDB object will have binary contents in the form of struct pmdb_object, which has been defined in this patch. Note that pmdb_object_lookup() is not concerned with the application API at all. It's only used within the PumiceDB private column-family for accessing the shadow metadata which PumiceDB stores on behalf of all application objects. The patch also implements a method for determining whether a write operation is pending to application object through the use of a term value held in the pmdb_object. A term which is == to the current term means that the a write is pending and no others may be accepted until it completes. It also means that the apply of the object (through commit) must reset that term value. The pmdb_object::term value is neutralized when a leader election occurs and the held term is < the current raft term. pmdb_sm_handler_client_write() is also coming along but still needs some work. It also uses the newly introduced lookup method to obtain the application's pumice metadata. The error handling is still a bit of mess (though this is somewhat expected).
PumiceDB needs to support supplementary atomic KV writes with both raft-entry writes and state machine application. This patch starts to implement a simple API for attaching KVs to struct raft_net_client_request so that these may be included in rockds write batches. One the raft-entry write end, pumiceDB must be updated so that the application object gets a pending marker placed into rocksDB atomically with the raft-entry. This is meant to prevent retried writes on the same seqno from entering raft and causing idempotency issues. On the state machine application side, the supplement will be raft itself. Here, raft will store some metadata marking which commits have been applied into rocksDB, again, with the goal of preventing idempotency related issues.
This patch adds the write supplements functions which are to be for passing KVs from the state machine back to the raft-server logic. Added a new raft-backend-api call: rib_sm_apply_opt(). This is called after the SM callback is run in commit-apply context. The SM is to present all KVs it wishes to have written into the backend - it does not write these itself! The raft backend implementation will execute the write itself and may encode other non-SM related metadata, such as the last-applied raft index.
Just some minor changes following a cursory review.
Use raft_client_net_request_error_set() instead of setting reply errors directly.
This patch adds the pmdb object as a KV to raft client request write supplement. The patch also implements the crc calculation of the pmdb object.
The raft_instance_backend rib_entry_write func pointer now accepts a raft_net_sm_write_supplements pointer. This pointer is optional and will be used (at this time) only by the rockdsDB backend. Note the write api may be (and should be) simplified in the future to accept one set of KVs instead the raft-entry pointer and a set of KVs. The raft-entry itself can be passed as a KV in the same set as the supplements.
Write supplements are now considered for both rsbr_entry_write() as well as rsbr_sm_apply_opt(), which is implemented in this patch.
pmdb_apply_sm_handler_t parameters have been modified to reflect the new rocksdb write model where writes are applied in raft backend context rather than in pumiceDB. This means that pumiceDB applications do not need to issue rocksDB write calls in order to store there KVs. pmdb_sm_handler() has now been modified to support RAFT_NET_CLIENT_REQ_TYPE_COMMIT. A new external function, PmdbWriteKV(), has been added in this patch. PmdbWriteKV() is used by pumiceDB applications to stage KVs for storing into rocksDB in the context of pmdb_apply_sm_handler_t. These KVs will be written atomically with any KVs added by pumiceDB.
Added a make target for it as well which builds a shared library.
pmdb_sm_handler_pmdb_sm_apply() was forgetting to unset the pending term element in the pmdb_object KV. This patch fixes the situation by adding the pmdb_obj to the sm_apply write supplement. Implement PmdbClose(). Add comments to the header files for the exported PMDB calls.
Add libpumice.so.1.0.1 to .gitignore
This test server uses the pumiceDB api to implement the same server behaviour found in raft_server_test.c. The idea, for now, is to reuse the same client (raft_client_test.c) to verify that pumiceDB achieves basic functionality.
Fix a few minor compilation problems and add to the makefile.
be1d65 removed an initialization call.
bergstartup
added a commit
that referenced
this pull request
Aug 10, 2022
Deletion of stale ctl entries using timeout
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