Merge pull request #846 from ApptiveGrid/BTree-DataPage-Recycle

Implement recyclePage: for Btree Data pages

src/Soil-Core-Tests/SoilBTreeTest.class.st

@@ -500,6 +500,30 @@ SoilBTreeTest >> testRemoveKey [
 	self should: [ index removeKey: 20  ] raise: KeyNotFound.
 ]
 
+{ #category : #tests }
+SoilBTreeTest >> testRemovePage [
+
+	| capacityFirst offset capacity iterator |
+	capacityFirst := index firstPage itemCapacity.
+	1 to: capacityFirst do: [ :n | 
+		index at: n put: (n asByteArrayOfSize: 8) ].
+	self assert: index pages size equals: 3.
+	offset := capacityFirst.
+	iterator := index newIterator.
+	2 to: 6 do: [ :p | 
+		index at: offset + 1 put: ((offset + 1) asByteArrayOfSize: 8).
+		capacity := index lastPage itemCapacity.
+		offset + 2 to:  (offset + capacity) do: [:n | .
+			index at: n put: (n asByteArrayOfSize: 8) ].
+		offset := offset + capacity ].
+	self assert: index pages size equals: 13.
+	index recyclePage: (index pages at: 3).
+	self assert: index pages size equals: 13.
+	"after, index 3 should not be a value in any index page item"
+	index indexPages do: [ :indexPage | self assert: (indexPage items noneSatisfy: [ :item | item value == 3 ]) ]
+
+]
+
 { #category : #tests }
 SoilBTreeTest >> testSize [
 

src/Soil-Core/SoilBTreeHeaderPage.class.st

@@ -27,6 +27,12 @@ SoilBTreeHeaderPage >> decreaseSize [
  	needWrite := true
 ]
 
+{ #category : #accessing }
+SoilBTreeHeaderPage >> firstFreePageIndex [
+
+	^ firstFreePageIndex
+]
+
 { #category : #accessing }
 SoilBTreeHeaderPage >> firstFreePageIndex: anObject [
 

src/Soil-Core/SoilBasicBTree.class.st

@@ -119,6 +119,16 @@ SoilBasicBTree >> pageClass [
 	^ SoilBTreeDataPage
 ]
 
+{ #category : #removing }
+SoilBasicBTree >> recyclePage: aPage [
+	"the header stays untouched even it it gets empty"
+	aPage isHeaderPage ifTrue: [ ^ aPage ].
+	"remove page from chain of item pages"
+	self removePage: aPage. 
+	"add page to free list chain"
+	^ self addToFreePages: aPage
+]
+
 { #category : #removing }
 SoilBasicBTree >> removeKey: key ifAbsent: aBlock [
 	| removedItem |
@@ -127,6 +137,26 @@ SoilBasicBTree >> removeKey: key ifAbsent: aBlock [
 	^removedItem value 
 ]
 
+{ #category : #removing }
+SoilBasicBTree >> removePage: aPage [
+	| iterator previousPage |
+	(aPage offset > 1) ifFalse: [ ^ aPage ].
+
+	"We use the iterator to find the previousPage, to change it's next pointer to my next"
+	iterator := self newIterator. 
+	previousPage := iterator findPreviousPageOf: aPage. 
+	previousPage next: aPage next.
+
+	"now remove all keys, this will update the index pages"
+
+	aPage items reverseDo: [ :item | item ifNotNil: [self removeKey: item key]  ].
+
+	"finally remove the page from the store"
+	store removePageAt: aPage offset.
+	^ aPage 
+
+]
+
 { #category : #accessing }
 SoilBasicBTree >> rootPage [
 	^ self store pageAt: 2

src/Soil-Core/SoilFreePage.class.st

@@ -56,6 +56,11 @@ SoilFreePage >> isDirty [
 	^ needWrite 
 ]
 
+{ #category : #testing }
+SoilFreePage >> isIndexPage [
+	^ false
+]
+
 { #category : #accessing }
 SoilFreePage >> label [ 
 	^ 'free page'

src/Soil-Core/SoilIndex.class.st

@@ -26,6 +26,32 @@ SoilIndex >> addDirtyPage: aPage [
 
 ]
 
+{ #category : #adding }
+SoilIndex >> addToFreePages: aPage [  
+	| currentFreePage newFreePage |
+	newFreePage := aPage asSoilFreePage.
+	store pageAt: aPage offset put: newFreePage.
+	currentFreePage := self firstFreePage
+		ifNil: [ 
+			"if there is no first free page yet make aPage the
+			first free page"
+			self headerPage firstFreePageIndex: newFreePage offset.
+			^ newFreePage ].
+	"if there is a first free page start scanning from here for a
+	free page that has room to store another free page"
+	[ currentFreePage hasRoom ] whileFalse: [ 
+		"if there is no room for the page to store and the current
+		free page does not have a next pointer we make aPage the 
+		next"
+		currentFreePage next isZero 
+			ifTrue: [
+				currentFreePage next: newFreePage offset.
+				^ newFreePage  ]
+			ifFalse: [ currentFreePage := store pageAt: currentFreePage next ]].
+	currentFreePage addPage: newFreePage.
+	^ newFreePage 
+]
+
 { #category : #private }
 SoilIndex >> at: key [ 
 	^ self 
@@ -91,6 +117,15 @@ SoilIndex >> first: anInteger [
 	^ self newIterator first: anInteger
 ]
 
+{ #category : #accessing }
+SoilIndex >> firstFreePage [
+	| index | 
+	index := self headerPage firstFreePageIndex.
+	^ index isZero 
+		ifTrue: [ ^ nil ]
+		ifFalse: [ store pageAt: index ]
+]
+
 { #category : #accessing }
 SoilIndex >> firstPage [
 	^ self headerPage

src/Soil-Core/SoilSkipList.class.st

@@ -14,32 +14,6 @@ SoilSkipList >> acceptSoil: aSoilVisitor [
 	^ aSoilVisitor visitSkipList: self
 ]
 
-{ #category : #adding }
-SoilSkipList >> addToFreePages: aPage [  
-	| currentFreePage newFreePage |
-	newFreePage := aPage asSoilFreePage.
-	store pageAt: aPage offset put: newFreePage.
-	currentFreePage := self firstFreePage
-		ifNil: [ 
-			"if there is no first free page yet make aPage the
-			first free page"
-			self headerPage firstFreePageIndex: newFreePage offset.
-			^ newFreePage ].
-	"if there is a first free page start scanning from here for a
-	free page that has room to store another free page"
-	[ currentFreePage hasRoom ] whileFalse: [ 
-		"if there is no room for the page to store and the current
-		free page does not have a next pointer we make aPage the 
-		next"
-		currentFreePage next isZero 
-			ifTrue: [
-				currentFreePage next: newFreePage offset.
-				^ newFreePage  ]
-			ifFalse: [ currentFreePage := store pageAt: currentFreePage next ]].
-	currentFreePage addPage: newFreePage.
-	^ newFreePage 
-]
-
 { #category : #'as yet unclassified' }
 SoilSkipList >> allocatePage [
 	^ self newPage 
@@ -72,15 +46,6 @@ SoilSkipList >> destroy [
 	path ensureDelete 
 ]
 
-{ #category : #accessing }
-SoilSkipList >> firstFreePage [
-	| offset | 
-	offset := self headerPage firstFreePageIndex.
-	^ offset isZero 
-		ifTrue: [ ^ nil ]
-		ifFalse: [ store pageAt: offset ]
-]
-
 { #category : #deleting }
 SoilSkipList >> flush [
 	self store flush