mirror of https://github.com/sqlite/sqlite
Simplify things by rolling the functionality of balance_shallower() into balance_nonroot(). (CVS 6808)
FossilOrigin-Name: 11750c6aee6aa05b2627ad9dfb2fbcdfe8944168
This commit is contained in:
danielk1977
parent
0b9f50d8aa
commit
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16
manifest
16
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@ -1,5 +1,5 @@
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C Enhance\sautoincrement\sso\sthat\sit\sworks\swith\striggers\sthat\salso\sdo\r\nautoincrement\sinserts,\seven\smultiple\sinserts\sinto\sthe\ssame\stable.\r\nTicket\s#3928\s(CVS\s6807)
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D 2009-06-23T20:28:54
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C Simplify\sthings\sby\srolling\sthe\sfunctionality\sof\sbalance_shallower()\sinto\sbalance_nonroot().\s(CVS\s6808)
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D 2009-06-24T05:40:34
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F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
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F Makefile.in 8b8fb7823264331210cddf103831816c286ba446
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F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
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@ -106,9 +106,9 @@ F src/auth.c 98db07c2088455797678eb1031f42d4d94d18a71
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F src/backup.c ff50af53184a5fd7bdee4d620b5dabef74717c79
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F src/bitvec.c 0ef0651714728055d43de7a4cdd95e703fac0119
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F src/btmutex.c 9b899c0d8df3bd68f527b0afe03088321b696d3c
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F src/btree.c 807e32c181e681ffd3468d114b5cb11c63984842
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F src/btree.c 699c333dd98db2498eb17ca43b2a5482c9dd098f
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F src/btree.h f70b694e8c163227369a66863b01fbff9009f323
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F src/btreeInt.h 7267e965e34314aa2bddbdde268b31e1034eda9c
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F src/btreeInt.h 55346bc14b939ad41b297942e8b1b581e960fb99
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F src/build.c d930b3899aea564f01a581e0e9429d92fb5f98f0
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F src/callback.c cb68b21b0d4ae7d11ae0e487933bce3323784dcf
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F src/complete.c 5ad5c6cd4548211867c204c41a126d73a9fbcea0
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@ -737,7 +737,7 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
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F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
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F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
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F tool/vdbe-compress.tcl 672f81d693a03f80f5ae60bfefacd8a349e76746
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P c5dc80e6bdd18a5ada728c8d5c9403ac233f1c9a
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R 8916621e1801546a3d0feafac918adbe
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U drh
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Z cb8dc29a045e11a78c5fa19e64b5f95b
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P 1330993de8eae7baeec24100216158063c9bdc19
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R a93d21d5217aa847ca2406219efba4db
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U danielk1977
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Z ce9bb99781cb9e1be1b1a4518af4f1e5
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@ -1 +1 @@
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1330993de8eae7baeec24100216158063c9bdc19
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11750c6aee6aa05b2627ad9dfb2fbcdfe8944168
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146
src/btree.c
146
src/btree.c
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@ -9,7 +9,7 @@
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** $Id: btree.c,v 1.641 2009/06/23 16:40:18 danielk1977 Exp $
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** $Id: btree.c,v 1.642 2009/06/24 05:40:34 danielk1977 Exp $
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**
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** This file implements a external (disk-based) database using BTrees.
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** See the header comment on "btreeInt.h" for additional information.
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@ -5388,47 +5388,6 @@ static int copyNodeContent(MemPage *pFrom, MemPage *pTo){
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return rc;
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}
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/*
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** This routine is called on the root page of a btree when the root
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** page contains no cells. This is an opportunity to make the tree
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** shallower by one level.
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*/
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static int balance_shallower(MemPage *pRoot, MemPage *pChild){
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/* The root page is empty but has one child. Transfer the
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** information from that one child into the root page if it
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** will fit. This reduces the depth of the tree by one.
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**
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** If the root page is page 1, it has less space available than
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** its child (due to the 100 byte header that occurs at the beginning
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** of the database fle), so it might not be able to hold all of the
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** information currently contained in the child. If this is the
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** case, then do not do the transfer. Leave page 1 empty except
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** for the right-pointer to the child page. The child page becomes
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** the virtual root of the tree.
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*/
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int rc = SQLITE_OK; /* Return code */
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int const hdr = pRoot->hdrOffset; /* Offset of root page header */
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assert( sqlite3_mutex_held(pRoot->pBt->mutex) );
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assert( pRoot->nCell==0 );
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assert( pChild->pgno==get4byte(&pRoot->aData[pRoot->hdrOffset+8]) );
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assert( hdr==0 || pRoot->pgno==1 );
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if( pChild->nFree>=hdr ){
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if( hdr ){
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rc = defragmentPage(pChild);
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}
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if( rc==SQLITE_OK ){
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rc = copyNodeContent(pChild, pRoot);
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}
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if( rc==SQLITE_OK ){
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rc = freePage(pChild);
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}
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}
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return rc;
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}
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/*
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** This routine redistributes cells on the iParentIdx'th child of pParent
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** (hereafter "the page") and up to 2 siblings so that all pages have about the
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@ -5922,38 +5881,60 @@ static int balance_nonroot(
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memcpy(&apNew[nNew-1]->aData[8], zChild, 4);
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}
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/* Fix the pointer-map entries for all the cells that were shifted around.
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** There are several different types of pointer-map entries that need to
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** be dealt with by this routine. Some of these have been set already, but
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** many have not. The following is a summary:
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**
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** 1) The entries associated with new sibling pages that were not
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** siblings when this function was called. These have already
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** been set. We don't need to worry about old siblings that were
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** moved to the free-list - the freePage() code has taken care
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** of those.
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**
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** 2) The pointer-map entries associated with the first overflow
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** page in any overflow chains used by new divider cells. These
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** have also already been taken care of by the insertCell() code.
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**
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** 3) If the sibling pages are not leaves, then the child pages of
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** cells stored on the sibling pages may need to be updated.
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**
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** 4) If the sibling pages are not internal intkey nodes, then any
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** overflow pages used by these cells may need to be updated
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** (internal intkey nodes never contain pointers to overflow pages).
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**
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** 5) If the sibling pages are not leaves, then the pointer-map
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** entries for the right-child pages of each sibling may need
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** to be updated.
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**
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** Cases 1 and 2 are dealt with above by other code. The following
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** block deals with cases 3 and 4. Since setting a pointer map entry
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** is a relatively expensive operation, this code only sets pointer
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** map entries for child or overflow pages that have actually moved
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** between pages. */
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if( ISAUTOVACUUM ){
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if( isRoot && pParent->nCell==0 && pParent->hdrOffset<=apNew[0]->nFree ){
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/* The root page of the b-tree now contains no cells. The only sibling
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** page is the right-child of the parent. Copy the contents of the
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** child page into the parent, decreasing the overall height of the
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** b-tree structure by one. This is described as the "balance-shallower"
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** sub-algorithm in some documentation.
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**
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** If this is an auto-vacuum database, the call to copyNodeContent()
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** sets all pointer-map entries corresponding to database image pages
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** for which the pointer is stored within the content being copied.
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**
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** The second assert below verifies that the child page is defragmented
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** (it must be, as it was just reconstructed using assemblePage()). This
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** is important if the parent page happens to be page 1 of the database
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** image. */
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assert( nNew==1 );
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assert( apNew[0]->nFree ==
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(get2byte(&apNew[0]->aData[5])-apNew[0]->cellOffset-apNew[0]->nCell*2)
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);
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if( SQLITE_OK==(rc = copyNodeContent(apNew[0], pParent)) ){
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rc = freePage(apNew[0]);
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}
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}else if( ISAUTOVACUUM ){
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/* Fix the pointer-map entries for all the cells that were shifted around.
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** There are several different types of pointer-map entries that need to
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** be dealt with by this routine. Some of these have been set already, but
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** many have not. The following is a summary:
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**
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** 1) The entries associated with new sibling pages that were not
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** siblings when this function was called. These have already
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** been set. We don't need to worry about old siblings that were
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** moved to the free-list - the freePage() code has taken care
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** of those.
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**
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** 2) The pointer-map entries associated with the first overflow
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** page in any overflow chains used by new divider cells. These
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** have also already been taken care of by the insertCell() code.
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**
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** 3) If the sibling pages are not leaves, then the child pages of
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** cells stored on the sibling pages may need to be updated.
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**
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** 4) If the sibling pages are not internal intkey nodes, then any
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** overflow pages used by these cells may need to be updated
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** (internal intkey nodes never contain pointers to overflow pages).
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**
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** 5) If the sibling pages are not leaves, then the pointer-map
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** entries for the right-child pages of each sibling may need
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** to be updated.
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**
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** Cases 1 and 2 are dealt with above by other code. The next
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** block deals with cases 3 and 4 and the one after that, case 5. Since
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** setting a pointer map entry is a relatively expensive operation, this
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** code only sets pointer map entries for child or overflow pages that have
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** actually moved between pages. */
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MemPage *pNew = apNew[0];
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MemPage *pOld = apCopy[0];
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int nOverflow = pOld->nOverflow;
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@ -6032,16 +6013,6 @@ static int balance_nonroot(
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TRACE(("BALANCE: finished: old=%d new=%d cells=%d\n",
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nOld, nNew, nCell));
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if( rc==SQLITE_OK && pParent->nCell==0 && isRoot ){
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/* The root page of the b-tree now contains no cells. If the root-page
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** is not also a leaf page, it will have a single child page. Call
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** balance_shallower to attempt to copy the contents of the single
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** child-page into the root page (this may not be possible if the
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** root page is page 1). */
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assert( nNew==1 );
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rc = balance_shallower(pParent, apNew[0]);
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}
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/*
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** Cleanup before returning.
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*/
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@ -6127,11 +6098,6 @@ static int balance_deeper(MemPage *pRoot, MemPage **ppChild){
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** balance_quick()
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** balance_deeper()
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** balance_nonroot()
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**
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** If built with SQLITE_DEBUG, pCur->pagesShuffled is set to true if
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** balance_shallower(), balance_deeper() or balance_nonroot() is called.
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** If none of these functions are invoked, pCur->pagesShuffled is left
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** unmodified.
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*/
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static int balance(BtCursor *pCur){
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int rc = SQLITE_OK;
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@ -6161,7 +6127,6 @@ static int balance(BtCursor *pCur){
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pCur->aiIdx[1] = 0;
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assert( pCur->apPage[1]->nOverflow );
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}
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VVA_ONLY( pCur->pagesShuffled = 1 );
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}else{
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break;
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}
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@ -6229,7 +6194,6 @@ static int balance(BtCursor *pCur){
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** balance_nonroot(), or just before this function returns, whichever
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** comes first. */
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pFree = pSpace;
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VVA_ONLY( pCur->pagesShuffled = 1 );
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}
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}
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@ -9,7 +9,7 @@
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** May you share freely, never taking more than you give.
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**
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*************************************************************************
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** $Id: btreeInt.h,v 1.48 2009/06/22 12:05:10 drh Exp $
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** $Id: btreeInt.h,v 1.49 2009/06/24 05:40:34 danielk1977 Exp $
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**
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** This file implements a external (disk-based) database using BTrees.
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** For a detailed discussion of BTrees, refer to
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@ -475,9 +475,6 @@ struct BtCursor {
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#ifndef SQLITE_OMIT_INCRBLOB
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u8 isIncrblobHandle; /* True if this cursor is an incr. io handle */
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Pgno *aOverflow; /* Cache of overflow page locations */
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#endif
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#ifndef NDEBUG
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u8 pagesShuffled; /* True if Btree pages are rearranged by balance()*/
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#endif
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i16 iPage; /* Index of current page in apPage */
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MemPage *apPage[BTCURSOR_MAX_DEPTH]; /* Pages from root to current page */
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