Very small performance increase and size reduction by removing unnecessary

ALWAYS() macros from the btree balance logic and replacing them with
special initialization of CellArray and some assert()s.

FossilOrigin-Name: 32b79041d9b6858e4ffade5841898619c7d25d20c4638bf85447a2ca9cc4a3d3

diff --git a/manifest b/manifest
index 098e85249a7656f1fa0a5f6dcf1c406445efb955..b54a84d33d5b4bc1281b9e525b9fbc0903ac838e 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Doc\stypo\sfix.\sNo\scode\schanges.
-D 2024-05-27T13:41:46.728
+C Very\ssmall\sperformance\sincrease\sand\ssize\sreduction\sby\sremoving\sunnecessary\nALWAYS()\smacros\sfrom\sthe\sbtree\sbalance\slogic\sand\sreplacing\sthem\swith\nspecial\sinitialization\sof\sCellArray\sand\ssome\sassert()s.
+D 2024-05-27T15:13:49.723
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -694,7 +694,7 @@ F src/auth.c 19b7ccacae3dfba23fc6f1d0af68134fa216e9040e53b0681b4715445ea030b4
 F src/backup.c 5c97e8023aab1ce14a42387eb3ae00ba5a0644569e3476f38661fa6f824c3523
 F src/bitvec.c 9eac5f42c11914d5ef00a75605bb205e934f435c579687f985f1f8b0995c8645
 F src/btmutex.c 79a43670447eacc651519a429f6ece9fd638563cf95b469d6891185ddae2b522
-F src/btree.c c786c0e9ee3d848e01e96fa3a84b0e44dbc80477b0accf406de810d87a7d0426
+F src/btree.c 1a77e763f03a775b5e7c17f4e2f043c46538b107c12e425ecc68cf78a71d9a51
 F src/btree.h 55066f513eb095db935169dab1dc2f7c7a747ef223c533f5d4ad4dfed346cbd0
 F src/btreeInt.h 98aadb6dcb77b012cab2574d6a728fad56b337fc946839b9898c4b4c969e30b6
 F src/build.c 237ccc0290d131d646be722f418e92ee0a38043aee25e7dfdc75f8ce5b3abe4e
@@ -2193,8 +2193,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 82365a45b96536c1146a384e5d3efce80a6ec469a54713c7f40bf15eb834b5fd
-R 69243fb48d2d86f0aae5c62167ad4060
-U stephan
-Z 7c55017839b224ee3043f5b1beb0d3bd
+P eaf07fe69f383938dd394f58cedad3f16f146d9b48e66bc1ba17446cf75ffb3f
+R dc12087fabeb41552a351cfb5dec1bee
+U drh
+Z 1b0c3733cd5c8aecb350c7623a6fceee
 # Remove this line to create a well-formed Fossil manifest.

diff --git a/manifest.uuid b/manifest.uuid
index d845d92d415e7d964e64085fc0bf69e38419ff35..8f8f2422fac387bd69ff0d6b412daee38c8b2491 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-eaf07fe69f383938dd394f58cedad3f16f146d9b48e66bc1ba17446cf75ffb3f
\ No newline at end of file
+32b79041d9b6858e4ffade5841898619c7d25d20c4638bf85447a2ca9cc4a3d3
\ No newline at end of file

diff --git a/src/btree.c b/src/btree.c
index aa41ec3ba2ae3cc79d8a9d30fad16c81e1552996..1c47ace501034e9cfc5f11465636688d56a22b3e 100644 (file)
--- a/src/btree.c
+++ b/src/btree.c
@@ -7567,8 +7567,8 @@ static int rebuildPage(
   if( j>(u32)usableSize ){ j = 0; }
   memcpy(&pTmp[j], &aData[j], usableSize - j);
 
-  for(k=0; ALWAYS(k<NB*2) && pCArray->ixNx[k]<=i; k++){}
-  assert( k<NB*2 );
+  assert( pCArray->ixNx[NB*2-1]>i );
+  for(k=0; pCArray->ixNx[k]<=i; k++){}
   pSrcEnd = pCArray->apEnd[k];
 
   pData = pEnd;
@@ -7651,8 +7651,8 @@ static int pageInsertArray(
   u8 *pEnd;                       /* Maximum extent of cell data */
   assert( CORRUPT_DB || pPg->hdrOffset==0 );    /* Never called on page 1 */
   if( iEnd<=iFirst ) return 0;
-  for(k=0; ALWAYS(k<NB*2) && pCArray->ixNx[k]<=i ; k++){}
-  assert( k<NB*2 );
+  assert( pCArray->ixNx[NB*2-1]>i );
+  for(k=0; pCArray->ixNx[k]<=i ; k++){}
   pEnd = pCArray->apEnd[k];
   while( 1 /*Exit by break*/ ){
     int sz, rc;
@@ -8172,7 +8172,9 @@ static int balance_nonroot(
   CellArray b;                 /* Parsed information on cells being balanced */
 
   memset(abDone, 0, sizeof(abDone));
-  memset(&b, 0, sizeof(b));
+  assert( sizeof(b) - sizeof(b.ixNx) == offsetof(CellArray,ixNx) );
+  memset(&b, 0, sizeof(b)-sizeof(b.ixNx));
+  b.ixNx[NB*2-1] = 0x7fffffff;
   pBt = pParent->pBt;
   assert( sqlite3_mutex_held(pBt->mutex) );
   assert( sqlite3PagerIswriteable(pParent->pDbPage) );
@@ -8763,8 +8765,8 @@ static int balance_nonroot(
     iOvflSpace += sz;
     assert( sz<=pBt->maxLocal+23 );
     assert( iOvflSpace <= (int)pBt->pageSize );
-    for(k=0; ALWAYS(k<NB*2) && b.ixNx[k]<=j; k++){}
-    assert( k<NB*2 );
+    assert( b.ixNx[NB*2-1]>j );
+    for(k=0; b.ixNx[k]<=j; k++){}
     pSrcEnd = b.apEnd[k];
     if( SQLITE_OVERFLOW(pSrcEnd, pCell, pCell+sz) ){
       rc = SQLITE_CORRUPT_BKPT;