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Investigate performance regression

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Performance has regressed following the hashtable change.  Speculation
that the hashtable format might not be right, and so there is more
cycling around the hashtree.  Logging added.
This commit is contained in:
martinsumner 2016-12-13 14:06:19 +00:00
parent 52499170c0
commit 8f775a88fd
2 changed files with 24 additions and 7 deletions
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24
src/leveled_cdb.erl
View file

@ -1092,9 +1092,14 @@ read_integerpairs(<<Int1:32, Int2:32, Rest/binary>>, Pairs) ->
%% false - don't check the CRC before returning key & value
%% loose_presence - confirm that the hash of the key is present
search_hash_table(_Handle, [], _Hash, _Key, _QuickCheck) ->
search_hash_table(Handle, Entries, Hash, Key, QuickCheck) ->
search_hash_table(Handle, Entries, Hash, Key, QuickCheck, 0).
search_hash_table(_Handle, [], _Hash, _Key, _QuickCheck, CycleCount) ->
log_cyclecount(CycleCount),
missing;
search_hash_table(Handle, [Entry|RestOfEntries], Hash, Key, QuickCheck) ->
search_hash_table(Handle, [Entry|RestOfEntries], Hash, Key,
QuickCheck, CycleCount) ->
{ok, _} = file:position(Handle, Entry),
{StoredHash, DataLoc} = read_next_2_integers(Handle),
case StoredHash of
@ -1111,15 +1116,26 @@ search_hash_table(Handle, [Entry|RestOfEntries], Hash, Key, QuickCheck) ->
RestOfEntries,
Hash,
Key,
QuickCheck);
QuickCheck,
CycleCount + 1);
_ ->
log_cyclecount(CycleCount),
KV
end;
%0 ->
% % Hash is 0 so key must be missing as 0 found before Hash matched
% missing;
_ ->
search_hash_table(Handle, RestOfEntries, Hash, Key, QuickCheck)
search_hash_table(Handle, RestOfEntries, Hash, Key,
QuickCheck, CycleCount + 1)
end.
log_cyclecount(CycleCount) ->
if
CycleCount > 8 ->
leveled_log:log("CDB15", [CycleCount]);
true ->
ok
end.
% Write Key and Value tuples into the CDB. Each tuple consists of a

7
src/leveled_log.erl
View file

@ -260,9 +260,10 @@
{"CDB13",
{info, "Write options of ~w"}},
{"CDB14",
{info, "Microsecond imings for hashtree build of "
++ "to_list ~w sort ~w build ~w"}}
{info, "Microsecond timings for hashtree build of "
++ "to_list ~w sort ~w build ~w"}},
{"CDB15",
{info, "Cycle count of ~w in hashtable search higher than expected~n"}}
])).