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Commitc6e6d29

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committed
First step in attempt to fix tree at runtime: create upper levels
and new root page if old root one was splitted but new root pagewasn't created.New code is protected by FixBTree bool flag setted to FALSE, sonothing should be affected by this untested approach.
1 parent19c4197 commitc6e6d29

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3 files changed

+282
-61
lines changed

3 files changed

+282
-61
lines changed

‎src/backend/access/nbtree/nbtinsert.c‎

Lines changed: 217 additions & 54 deletions
Original file line numberDiff line numberDiff line change
@@ -8,7 +8,7 @@
88
*
99
*
1010
* IDENTIFICATION
11-
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.76 2001/01/24 19:42:48 momjian Exp $
11+
* $Header: /cvsroot/pgsql/src/backend/access/nbtree/nbtinsert.c,v 1.77 2001/01/26 01:24:31 vadim Exp $
1212
*
1313
*-------------------------------------------------------------------------
1414
*/
@@ -34,7 +34,9 @@ typedef struct
3434
intbest_delta;/* best size delta so far */
3535
}FindSplitData;
3636

37-
void_bt_newroot(Relationrel,Bufferlbuf,Bufferrbuf);
37+
Buffer_bt_fixroot(Relationrel,Bufferoldrootbuf,boolrelease);
38+
39+
staticBuffer_bt_newroot(Relationrel,Bufferlbuf,Bufferrbuf);
3840

3941
staticTransactionId_bt_check_unique(Relationrel,BTItembtitem,
4042
RelationheapRel,Bufferbuf,
@@ -44,6 +46,8 @@ static InsertIndexResult _bt_insertonpg(Relation rel, Buffer buf,
4446
intkeysz,ScanKeyscankey,
4547
BTItembtitem,
4648
OffsetNumberafteritem);
49+
staticvoid_bt_insertuple(Relationrel,Bufferbuf,
50+
Sizeitemsz,BTItembtitem,OffsetNumbernewitemoff);
4751
staticBuffer_bt_split(Relationrel,Bufferbuf,OffsetNumberfirstright,
4852
OffsetNumbernewitemoff,Sizenewitemsz,
4953
BTItemnewitem,boolnewitemonleft,
@@ -456,9 +460,14 @@ _bt_insertonpg(Relation rel,
456460

457461
if (is_root)
458462
{
463+
Bufferrootbuf;
464+
459465
Assert(stack== (BTStack)NULL);
460466
/* create a new root node and release the split buffers */
461-
_bt_newroot(rel,buf,rbuf);
467+
rootbuf=_bt_newroot(rel,buf,rbuf);
468+
_bt_wrtbuf(rel,rootbuf);
469+
_bt_wrtbuf(rel,rbuf);
470+
_bt_wrtbuf(rel,buf);
462471
}
463472
else
464473
{
@@ -519,52 +528,11 @@ _bt_insertonpg(Relation rel,
519528
}
520529
else
521530
{
522-
START_CRIT_SECTION();
523-
_bt_pgaddtup(rel,page,itemsz,btitem,newitemoff,"page");
524531
itup_off=newitemoff;
525532
itup_blkno=BufferGetBlockNumber(buf);
526-
/* XLOG stuff */
527-
{
528-
xl_btree_insertxlrec;
529-
uint8flag=XLOG_BTREE_INSERT;
530-
XLogRecPtrrecptr;
531-
XLogRecDatardata[2];
532-
BTItemDatatruncitem;
533533

534-
xlrec.target.node=rel->rd_node;
535-
ItemPointerSet(&(xlrec.target.tid),BufferGetBlockNumber(buf),newitemoff);
536-
rdata[0].buffer=InvalidBuffer;
537-
rdata[0].data= (char*)&xlrec;
538-
rdata[0].len=SizeOfBtreeInsert;
539-
rdata[0].next=&(rdata[1]);
540-
541-
/* Read comments in _bt_pgaddtup */
542-
if (!(P_ISLEAF(lpageop))&&newitemoff==P_FIRSTDATAKEY(lpageop))
543-
{
544-
truncitem=*btitem;
545-
truncitem.bti_itup.t_info=sizeof(BTItemData);
546-
rdata[1].data= (char*)&truncitem;
547-
rdata[1].len=sizeof(BTItemData);
548-
}
549-
else
550-
{
551-
rdata[1].data= (char*)btitem;
552-
rdata[1].len=IndexTupleDSize(btitem->bti_itup)+
553-
(sizeof(BTItemData)-sizeof(IndexTupleData));
554-
}
555-
rdata[1].buffer=buf;
556-
rdata[1].next=NULL;
534+
_bt_insertuple(rel,buf,itemsz,btitem,newitemoff);
557535

558-
if (P_ISLEAF(lpageop))
559-
flag |=XLOG_BTREE_LEAF;
560-
561-
recptr=XLogInsert(RM_BTREE_ID,flag,rdata);
562-
563-
PageSetLSN(page,recptr);
564-
PageSetSUI(page,ThisStartUpID);
565-
}
566-
567-
END_CRIT_SECTION();
568536
/* Write out the updated page and release pin/lock */
569537
_bt_wrtbuf(rel,buf);
570538
}
@@ -576,6 +544,57 @@ _bt_insertonpg(Relation rel,
576544
returnres;
577545
}
578546

547+
staticvoid
548+
_bt_insertuple(Relationrel,Bufferbuf,
549+
Sizeitemsz,BTItembtitem,OffsetNumbernewitemoff)
550+
{
551+
Pagepage=BufferGetPage(buf);
552+
BTPageOpaquepageop= (BTPageOpaque)PageGetSpecialPointer(page);
553+
554+
START_CRIT_SECTION();
555+
_bt_pgaddtup(rel,page,itemsz,btitem,newitemoff,"page");
556+
/* XLOG stuff */
557+
{
558+
xl_btree_insertxlrec;
559+
uint8flag=XLOG_BTREE_INSERT;
560+
XLogRecPtrrecptr;
561+
XLogRecDatardata[2];
562+
BTItemDatatruncitem;
563+
xlrec.target.node=rel->rd_node;
564+
ItemPointerSet(&(xlrec.target.tid),BufferGetBlockNumber(buf),newitemoff);
565+
rdata[0].buffer=InvalidBuffer;
566+
rdata[0].data= (char*)&xlrec;
567+
rdata[0].len=SizeOfBtreeInsert;
568+
rdata[0].next=&(rdata[1]);
569+
570+
/* Read comments in _bt_pgaddtup */
571+
if (!(P_ISLEAF(pageop))&&newitemoff==P_FIRSTDATAKEY(pageop))
572+
{
573+
truncitem=*btitem;
574+
truncitem.bti_itup.t_info=sizeof(BTItemData);
575+
rdata[1].data= (char*)&truncitem;
576+
rdata[1].len=sizeof(BTItemData);
577+
}
578+
else
579+
{
580+
rdata[1].data= (char*)btitem;
581+
rdata[1].len=IndexTupleDSize(btitem->bti_itup)+
582+
(sizeof(BTItemData)-sizeof(IndexTupleData));
583+
}
584+
rdata[1].buffer=buf;
585+
rdata[1].next=NULL;
586+
if (P_ISLEAF(pageop))
587+
flag |=XLOG_BTREE_LEAF;
588+
589+
recptr=XLogInsert(RM_BTREE_ID,flag,rdata);
590+
591+
PageSetLSN(page,recptr);
592+
PageSetSUI(page,ThisStartUpID);
593+
}
594+
595+
END_CRIT_SECTION();
596+
}
597+
579598
/*
580599
*_bt_split() -- split a page in the btree.
581600
*
@@ -1130,11 +1149,12 @@ _bt_getstackbuf(Relation rel, BTStack stack)
11301149
*graph.
11311150
*
11321151
*On entry, lbuf (the old root) and rbuf (its new peer) are write-
1133-
*locked. On exit, a new root page exists with entries for the
1134-
*two new children. The new root page is neither pinned nor locked, and
1135-
*we have also written out lbuf and rbuf and dropped their pins/locks.
1152+
*locked. On exit, a new root page exists with entries for the
1153+
*two new children, metapage is updated and unlocked/unpinned.
1154+
* The new root buffer is returned to caller which has to unlock/unpin
1155+
* lbuf, rbuf & rootbuf.
11361156
*/
1137-
void
1157+
staticBuffer
11381158
_bt_newroot(Relationrel,Bufferlbuf,Bufferrbuf)
11391159
{
11401160
Bufferrootbuf;
@@ -1257,13 +1277,156 @@ _bt_newroot(Relation rel, Buffer lbuf, Buffer rbuf)
12571277
}
12581278
END_CRIT_SECTION();
12591279

1260-
/* write and let go of the new root buffer */
1261-
_bt_wrtbuf(rel,rootbuf);
1280+
/* write and let go of metapage buffer */
12621281
_bt_wrtbuf(rel,metabuf);
12631282

1264-
/* update and release new sibling, and finally the old root */
1265-
_bt_wrtbuf(rel,rbuf);
1266-
_bt_wrtbuf(rel,lbuf);
1283+
return(rootbuf);
1284+
}
1285+
1286+
/*
1287+
* In the event old root page was splitted but no new one was created we
1288+
* build required parent levels keeping write lock on old root page.
1289+
* Note: it's assumed that old root page' btpo_parent points to meta page,
1290+
* ie not to parent page. On exit, new root page buffer is write locked.
1291+
* If "release" is TRUE then oldrootbuf will be released immediately
1292+
* after upper level is builded.
1293+
*/
1294+
Buffer
1295+
_bt_fixroot(Relationrel,Bufferoldrootbuf,boolrelease)
1296+
{
1297+
Bufferrootbuf;
1298+
BlockNumberrootblk;
1299+
Pagerootpage;
1300+
XLogRecPtrrootLSN;
1301+
Pageoldrootpage=BufferGetPage(oldrootbuf);
1302+
BTPageOpaqueoldrootopaque= (BTPageOpaque)
1303+
PageGetSpecialPointer(oldrootpage);
1304+
Bufferbuf,leftbuf,rightbuf;
1305+
Pagepage,leftpage,rightpage;
1306+
BTPageOpaqueopaque,leftopaque,rightopaque;
1307+
OffsetNumbernewitemoff;
1308+
BTItembtitem,ritem;
1309+
Sizeitemsz;
1310+
1311+
if (!P_LEFTMOST(oldrootopaque)||P_RIGHTMOST(oldrootopaque))
1312+
elog(ERROR,"bt_fixroot: not valid old root page");
1313+
1314+
/* Read right neighbor and create new root page*/
1315+
leftbuf=_bt_getbuf(rel,oldrootopaque->btpo_next,BT_WRITE);
1316+
leftpage=BufferGetPage(leftbuf);
1317+
leftopaque= (BTPageOpaque)PageGetSpecialPointer(leftpage);
1318+
rootbuf=_bt_newroot(rel,oldrootbuf,leftbuf);
1319+
rootpage=BufferGetPage(rootbuf);
1320+
rootLSN=PageGetLSN(rootpage);
1321+
rootblk=BufferGetBlockNumber(rootbuf);
1322+
1323+
/*
1324+
* Update LSN & StartUpID of old root buffer and its neighbor to
1325+
* ensure that they will be written on disk after logging new
1326+
* root creation. Unfortunately, for the moment (?) we do not
1327+
* log this operation and so possibly break our rule to log entire
1328+
* page content of first after checkpoint modification.
1329+
*/
1330+
HOLD_INTERRUPTS();
1331+
oldrootopaque->btpo_parent=rootblk;
1332+
leftopaque->btpo_parent=rootblk;
1333+
PageSetLSN(oldrootpage,rootLSN);
1334+
PageSetSUI(oldrootpage,ThisStartUpID);
1335+
PageSetLSN(leftpage,rootLSN);
1336+
PageSetSUI(leftpage,ThisStartUpID);
1337+
RESUME_INTERRUPTS();
1338+
1339+
/* parent page where to insert pointers */
1340+
buf=rootbuf;
1341+
page=BufferGetPage(buf);
1342+
opaque= (BTPageOpaque)PageGetSpecialPointer(page);
1343+
1344+
/*
1345+
* Now read other pages (if any) on level and add them to new root.
1346+
* If concurrent process will split one of pages on this level then it
1347+
* will notice either btpo_parent == metablock or btpo_parent == rootblk.
1348+
* In first case it will give up its locks and try to lock leftmost page
1349+
* buffer (oldrootbuf) to fix root - ie it will wait for us and let us
1350+
* continue. In second case it will try to lock rootbuf keeping its locks
1351+
* on buffers we already passed, also waiting for us. If we'll have to
1352+
* unlock rootbuf (split it) and that process will have to split page
1353+
* of new level we created (level of rootbuf) then it will wait while
1354+
* we create upper level. Etc.
1355+
*/
1356+
while(!P_RIGHTMOST(leftopaque))
1357+
{
1358+
rightbuf=_bt_getbuf(rel,leftopaque->btpo_next,BT_WRITE);
1359+
rightpage=BufferGetPage(rightbuf);
1360+
rightopaque= (BTPageOpaque)PageGetSpecialPointer(rightpage);
1361+
1362+
/* Update LSN & StartUpID (see comments above) */
1363+
HOLD_INTERRUPTS();
1364+
rightopaque->btpo_parent=rootblk;
1365+
if (XLByteLT(PageGetLSN(rightpage),rootLSN))
1366+
PageSetLSN(rightpage,rootLSN);
1367+
PageSetSUI(rightpage,ThisStartUpID);
1368+
RESUME_INTERRUPTS();
1369+
1370+
ritem= (BTItem)PageGetItem(leftpage,PageGetItemId(leftpage,P_HIKEY));
1371+
btitem=_bt_formitem(&(ritem->bti_itup));
1372+
ItemPointerSet(&(btitem->bti_itup.t_tid),leftopaque->btpo_next,P_HIKEY);
1373+
itemsz=IndexTupleDSize(btitem->bti_itup)
1374+
+ (sizeof(BTItemData)-sizeof(IndexTupleData));
1375+
itemsz=MAXALIGN(itemsz);
1376+
1377+
newitemoff=OffsetNumberNext(PageGetMaxOffsetNumber(page));
1378+
1379+
if (PageGetFreeSpace(page)<itemsz)
1380+
{
1381+
Buffernewbuf;
1382+
OffsetNumberfirstright;
1383+
OffsetNumberitup_off;
1384+
BlockNumberitup_blkno;
1385+
boolnewitemonleft;
1386+
1387+
firstright=_bt_findsplitloc(rel,page,
1388+
newitemoff,itemsz,&newitemonleft);
1389+
newbuf=_bt_split(rel,buf,firstright,
1390+
newitemoff,itemsz,btitem,newitemonleft,
1391+
&itup_off,&itup_blkno);
1392+
/* Keep lock on new "root" buffer ! */
1393+
if (buf!=rootbuf)
1394+
_bt_relbuf(rel,buf,BT_WRITE);
1395+
buf=newbuf;
1396+
page=BufferGetPage(buf);
1397+
opaque= (BTPageOpaque)PageGetSpecialPointer(page);
1398+
}
1399+
else
1400+
_bt_insertuple(rel,buf,itemsz,btitem,newitemoff);
1401+
1402+
/* give up left buffer */
1403+
_bt_relbuf(rel,leftbuf,BT_WRITE);
1404+
leftbuf=rightbuf;
1405+
leftpage=rightpage;
1406+
leftopaque=rightopaque;
1407+
}
1408+
1409+
/* give up rightmost page buffer */
1410+
_bt_relbuf(rel,leftbuf,BT_WRITE);
1411+
1412+
/*
1413+
* Here we hold locks on old root buffer, new root buffer we've
1414+
* created with _bt_newroot() - rootbuf, - and buf we've used
1415+
* for last insert ops - buf. If rootbuf != buf then we have to
1416+
* create at least one more level. And if "release" is TRUE
1417+
* (ie we've already created some levels) then we give up
1418+
* oldrootbuf.
1419+
*/
1420+
if (release)
1421+
_bt_relbuf(rel,oldrootbuf,BT_WRITE);
1422+
1423+
if (rootbuf!=buf)
1424+
{
1425+
_bt_relbuf(rel,buf,BT_WRITE);
1426+
return(_bt_fixroot(rel,rootbuf, true));
1427+
}
1428+
1429+
return(rootbuf);
12671430
}
12681431

12691432
/*

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