fix(server): mget crash on same key get #2474
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Signed-off-by: adi_holden <adi@dragonflydb.io>
This reverts commit f69f2ec.
Signed-off-by: adi_holden <adi@dragonflydb.io>
adiholden
requested review from
romange and
kostasrim
and removed request for
romange
kostasrim
previously approved these changes
Jan 25, 2024
| @@ -279,6 +279,39 @@ TEST_F(StringFamilyTest, MGetCachingModeBug2276) { | |||
| EXPECT_GT(bumps2, bumps1); | |||
| } | |||
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| TEST_F(StringFamilyTest, MGetCachingModeBug2465) { | |||
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Nice! I was about to ask for a test and you pushed :)
romange
previously approved these changes
Jan 25, 2024
| @@ -121,7 +121,7 @@ class PrimeBumpPolicy { | |||
| : bumped_items_(bumped_items) { | |||
| } | |||
| // returns true if key can be made less important for eviction (opposite of bump up) | |||
| bool CanBumpDown(const CompactObj& obj) const { | |||
| bool CanBump(const CompactObj& obj) const { | |||
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Please update comment as well
src/server/string_family.cc
Outdated
| @@ -494,18 +494,18 @@ class SetResultBuilder { | |||
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| SinkReplyBuilder::MGetResponse OpMGet(bool fetch_mcflag, bool fetch_mcver, const Transaction* t, | |||
| EngineShard* shard) { | |||
| auto keys = t->GetShardArgs(shard->shard_id()); | |||
| DCHECK(!keys.empty()); | |||
| auto args = t->GetShardArgs(shard->shard_id()); | |||
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Can you please still keep the 'keys' name here?
Signed-off-by: adi_holden <adi@dragonflydb.io>
Signed-off-by: adi_holden <adi@dragonflydb.io>
Signed-off-by: adi_holden <adi@dragonflydb.io>
romange
approved these changes
Jan 28, 2024
romange
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Nov 9, 2024
This pr #2474 introduced iterator protection by tracking which keys where bumped up during the transaction operation. This was done by managing keys view set. However, this can be simplified using fingerprints. Also, fingerprints do not require that the original keys exist. In addition, this #3241 PR introduces FetchedItemsRestorer that tracks bumped set and saves it to protect against fiber context switch. My claim is that it's redundant. Since we only keep the auto-laundering iterators, when a fiber preempts these iterators recognize it (see IteratorT::LaunderIfNeeded) and refresh themselves anyway. To summarize: fetched_items_ protect us from iterator invalidation during atomic scenarios, and auto-laundering protects us from everything else, so fetched_items_ can be cleared in that case. Signed-off-by: Roman Gershman <roman@dragonflydb.io>
romange
added a commit
that referenced
this pull request
Nov 13, 2024
This pr #2474 introduced iterator protection by tracking which keys where bumped up during the transaction operation. This was done by managing keys view set. However, this can be simplified using fingerprints. Also, fingerprints do not require that the original keys exist. In addition, this #3241 PR introduces FetchedItemsRestorer that tracks bumped set and saves it to protect against fiber context switch. My claim is that it's redundant. Since we only keep the auto-laundering iterators, when a fiber preempts these iterators recognize it (see IteratorT::LaunderIfNeeded) and refresh themselves anyway. To summarize: fetched_items_ protect us from iterator invalidation during atomic scenarios, and auto-laundering protects us from everything else, so fetched_items_ can be cleared in that case. Signed-off-by: Roman Gershman <roman@dragonflydb.io>
romange
added a commit
that referenced
this pull request
Nov 13, 2024
* chore: simplify BumpUps deduplication This pr #2474 introduced iterator protection by tracking which keys where bumped up during the transaction operation. This was done by managing keys view set. However, this can be simplified using fingerprints. Also, fingerprints do not require that the original keys exist. In addition, this #3241 PR introduces FetchedItemsRestorer that tracks bumped set and saves it to protect against fiber context switch. My claim is that it's redundant. Since we only keep the auto-laundering iterators, when a fiber preempts these iterators recognize it (see IteratorT::LaunderIfNeeded) and refresh themselves anyway. To summarize: fetched_items_ protect us from iterator invalidation during atomic scenarios, and auto-laundering protects us from everything else, so fetched_items_ can be cleared in that case. --------- Signed-off-by: Roman Gershman <roman@dragonflydb.io>
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fix: #2465
the bug: on cache mode mget bumps up items. When executing mget with the same key several times i.e mget key key we will invalidate the iterator when we bump up the item in dash table.
the fix: bump up/down items only once by using bumped_items set
This PR also reverts c225113
and updates the bumped stats and bumped_items set if the item was bumped