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h2database
Commits
bbf19a56
提交
bbf19a56
authored
6 年前
作者:
Andrei Tokar
浏览文件
操作
浏览文件
下载
电子邮件补丁
差异文件
TransactionMap::sizeAsLong() optimized - temp map eliminated
上级
9e734920
显示空白字符变更
内嵌
并排
正在显示
1 个修改的文件
包含
54 行增加
和
40 行删除
+54
-40
TransactionMap.java
h2/src/main/org/h2/mvstore/tx/TransactionMap.java
+54
-40
没有找到文件。
h2/src/main/org/h2/mvstore/tx/TransactionMap.java
浏览文件 @
bbf19a56
...
@@ -70,6 +70,11 @@ public class TransactionMap<K, V> {
...
@@ -70,6 +70,11 @@ public class TransactionMap<K, V> {
public
long
sizeAsLong
()
{
public
long
sizeAsLong
()
{
TransactionStore
store
=
transaction
.
store
;
TransactionStore
store
=
transaction
.
store
;
// The purpose of the following loop is to get a coherent picture
// of a state of three independent volatile / atomic variables,
// which they had at some recent moment in time.
// In order to get such a "snapshot", we wait for a moment of silence,
// when none of the variables concurrently changes it's value.
BitSet
committingTransactions
;
BitSet
committingTransactions
;
MVMap
.
RootReference
mapRootReference
;
MVMap
.
RootReference
mapRootReference
;
MVMap
.
RootReference
undoLogRootReference
;
MVMap
.
RootReference
undoLogRootReference
;
...
@@ -79,58 +84,67 @@ public class TransactionMap<K, V> {
...
@@ -79,58 +84,67 @@ public class TransactionMap<K, V> {
undoLogRootReference
=
store
.
undoLog
.
getRoot
();
undoLogRootReference
=
store
.
undoLog
.
getRoot
();
}
while
(
committingTransactions
!=
store
.
committingTransactions
.
get
()
||
}
while
(
committingTransactions
!=
store
.
committingTransactions
.
get
()
||
mapRootReference
!=
map
.
getRoot
());
mapRootReference
!=
map
.
getRoot
());
// Now we have a snapshot, where mapRootReference points to state of the map,
// undoLogRootReference captures the state of undo log
// and committingTransactions mask tells us which of seemingly uncommitted changes
// should be considered as committed.
// Subsequent processing uses this snapshot info only.
Page
undoRootPage
=
undoLogRootReference
.
root
;
Page
undoRootPage
=
undoLogRootReference
.
root
;
long
undoLogSize
=
undoRootPage
.
getTotalCount
();
long
undoLogSize
=
undoRootPage
.
getTotalCount
();
Page
mapRootPage
=
mapRootReference
.
root
;
Page
mapRootPage
=
mapRootReference
.
root
;
long
size
=
mapRootPage
.
getTotalCount
();
long
size
=
mapRootPage
.
getTotalCount
();
// if we are looking at the map without any uncommitted values
if
(
undoLogSize
==
0
)
{
if
(
undoLogSize
==
0
)
{
return
size
;
return
size
;
}
}
if
(
undoLogSize
>
size
)
{
// the undo log is larger than the map -
// Entries describing removals from the map by this transaction and all transactions,
// count the entries of the map
// which are committed but not closed yet,
size
=
0
;
// and antries about additions to the map by other uncommitted transactions were counted,
// but they should not contribute into total count.
if
(
2
*
undoLogSize
>
size
)
{
// the undo log is larger than half of the map - scan the entries of the map directly
Cursor
<
K
,
VersionedValue
>
cursor
=
new
Cursor
<>(
mapRootPage
,
null
);
Cursor
<
K
,
VersionedValue
>
cursor
=
new
Cursor
<>(
mapRootPage
,
null
);
while
(
cursor
.
hasNext
())
{
while
(
cursor
.
hasNext
())
{
K
key
=
cursor
.
next
();
cursor
.
next
();
VersionedValue
data
=
cursor
.
getValue
();
VersionedValue
currentValue
=
cursor
.
getValue
();
data
=
getValue
(
data
,
committingTransactions
);
assert
currentValue
!=
null
;
if
(
data
!=
null
&&
data
.
value
!=
null
)
{
long
operationId
=
currentValue
.
getOperationId
();
size
++;
if
(
operationId
!=
0
)
{
// skip committed entries
int
txId
=
TransactionStore
.
getTransactionId
(
operationId
);
boolean
isVisible
=
txId
==
transaction
.
transactionId
||
committingTransactions
.
get
(
txId
);
Object
v
=
isVisible
?
currentValue
.
value
:
currentValue
.
getCommittedValue
();
if
(
v
==
null
)
{
--
size
;
}
}
}
}
return
size
;
}
}
// the undo log is smaller than the map -
}
else
{
// scan the undo log and subtract invisible entries
// The undo log is much smaller than the map - scan the undo log, and then lookup relevant map entry.
MVMap
<
Object
,
Integer
>
temp
=
store
.
createTempMap
();
try
{
Cursor
<
Long
,
Object
[]>
cursor
=
new
Cursor
<>(
undoRootPage
,
null
);
Cursor
<
Long
,
Object
[]>
cursor
=
new
Cursor
<>(
undoRootPage
,
null
);
while
(
cursor
.
hasNext
())
{
while
(
cursor
.
hasNext
())
{
cursor
.
next
();
cursor
.
next
();
Object
[]
op
=
cursor
.
getValue
();
Object
op
[]
=
cursor
.
getValue
();
int
m
=
(
int
)
op
[
0
];
if
((
int
)
op
[
0
]
==
map
.
getId
())
{
if
(
m
!=
map
.
getId
())
{
VersionedValue
currentValue
=
map
.
get
(
mapRootPage
,
op
[
1
]);
// a different map - ignore
// If map entry is not there, then we never counted it, in the first place, so skip it.
continue
;
// This is possible when undo entry exists because it belongs
// to a committed but not yet closed transaction,
// and it was later deleted by some other already committed and closed transaction.
if
(
currentValue
!=
null
)
{
// only the last undo entry for any given map key should be considered
long
operationId
=
cursor
.
getKey
();
if
(
currentValue
.
getOperationId
()
==
operationId
)
{
int
txId
=
TransactionStore
.
getTransactionId
(
operationId
);
boolean
isVisible
=
txId
==
transaction
.
transactionId
||
committingTransactions
.
get
(
txId
);
Object
v
=
isVisible
?
currentValue
.
value
:
currentValue
.
getCommittedValue
();
if
(
v
==
null
)
{
--
size
;
}
}
}
@SuppressWarnings
(
"unchecked"
)
K
key
=
(
K
)
op
[
1
];
VersionedValue
data
=
map
.
get
(
mapRootPage
,
key
);
data
=
getValue
(
data
,
committingTransactions
);
if
(
data
==
null
||
data
.
value
==
null
)
{
Integer
old
=
temp
.
put
(
key
,
1
);
// count each key only once (there might be
// multiple
// changes for the same key)
if
(
old
==
null
)
{
size
--;
}
}
}
}
}
}
}
finally
{
transaction
.
store
.
store
.
removeMap
(
temp
);
}
}
return
size
;
return
size
;
}
}
...
@@ -623,10 +637,10 @@ public class TransactionMap<K, V> {
...
@@ -623,10 +637,10 @@ public class TransactionMap<K, V> {
TransactionStore
store
=
transactionMap
.
transaction
.
store
;
TransactionStore
store
=
transactionMap
.
transaction
.
store
;
MVMap
<
K
,
VersionedValue
>
map
=
transactionMap
.
map
;
MVMap
<
K
,
VersionedValue
>
map
=
transactionMap
.
map
;
// The purpose of the following loop is to get a coherent picture
// The purpose of the following loop is to get a coherent picture
// of a state of two independent volatile / atomic variables
// of a state of two independent volatile / atomic variables
,
// which they had at some recent moment in time.
// which they had at some recent moment in time.
// In order to get such a "snapshot", we wait for a moment of silence
// In order to get such a "snapshot", we wait for a moment of silence
,
// when neither of the variables concurrently ch
e
nges it's value.
// when neither of the variables concurrently ch
a
nges it's value.
BitSet
committingTransactions
;
BitSet
committingTransactions
;
MVMap
.
RootReference
mapRootReference
;
MVMap
.
RootReference
mapRootReference
;
do
{
do
{
...
...
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