Avoid constantly freeing and reallocing small internal buffers associated with

LSM cursors. Instead, allow them to persist for the lifetime of the cursor if
they are LSM_SEGMENTPTR_FREE_THRESHOLD (default 1024) bytes or smaller.

FossilOrigin-Name: bacfe8cb3e4d3be736c6789b2ce55ef5603e5c7a289b05b37cae2203cd7f2290

diff --git a/ext/lsm1/lsm_sorted.c b/ext/lsm1/lsm_sorted.c
index c7b03c8452d7d90859b0e70d9439c31d4811f0f0..de5a332db8de346dba340200af8034d2b894e6b5 100644 (file)
--- a/ext/lsm1/lsm_sorted.c
+++ b/ext/lsm1/lsm_sorted.c
@@ -98,6 +98,11 @@
 #define PGFTR_SKIP_NEXT_FLAG   0x0002
 #define PGFTR_SKIP_THIS_FLAG   0x0004
 
+
+#ifndef LSM_SEGMENTPTR_FREE_THRESHOLD
+# define LSM_SEGMENTPTR_FREE_THRESHOLD 1024
+#endif
+
 typedef struct SegmentPtr SegmentPtr;
 typedef struct Blob Blob;
 
@@ -1148,7 +1153,11 @@ static void sortedSplitkey(lsm_db *pDb, Level *pLevel, int *pRc){
   *pRc = rc;
 }
 
-static void segmentPtrReset(SegmentPtr *pPtr){
+/*
+** Reset a segment cursor. Also free its buffers if they are nThreshold
+** bytes or larger in size.
+*/
+static void segmentPtrReset(SegmentPtr *pPtr, int nThreshold){
   lsmFsPageRelease(pPtr->pPg);
   pPtr->pPg = 0;
   pPtr->nCell = 0;
@@ -1158,8 +1167,8 @@ static void segmentPtrReset(SegmentPtr *pPtr){
   pPtr->nVal = 0;
   pPtr->eType = 0;
   pPtr->iCell = 0;
-  sortedBlobFree(&pPtr->blob1);
-  sortedBlobFree(&pPtr->blob2);
+  if( pPtr->blob1.nAlloc>=nThreshold ) sortedBlobFree(&pPtr->blob1);
+  if( pPtr->blob2.nAlloc>=nThreshold ) sortedBlobFree(&pPtr->blob2);
 }
 
 static int segmentPtrIgnoreSeparators(MultiCursor *pCsr, SegmentPtr *pPtr){
@@ -1206,7 +1215,7 @@ static int segmentPtrAdvance(
           rtTopic(pPtr->eType), pPtr->pKey, pPtr->nKey,
           pLvl->iSplitTopic, pLvl->pSplitKey, pLvl->nSplitKey
       );
-      if( res<0 ) segmentPtrReset(pPtr);
+      if( res<0 ) segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
     }
 
     if( pPtr->pPg==0 && (svFlags & LSM_END_DELETE) ){
@@ -1275,7 +1284,7 @@ static int segmentPtrEnd(MultiCursor *pCsr, SegmentPtr *pPtr, int bLast){
           rtTopic(pPtr->eType), pPtr->pKey, pPtr->nKey,
           pLvl->iSplitTopic, pLvl->pSplitKey, pLvl->nSplitKey
       );
-      if( res<0 ) segmentPtrReset(pPtr);
+      if( res<0 ) segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
     }
   }
   
@@ -1611,7 +1620,7 @@ static int segmentPtrFwdPointer(
       rc = ptrFwdPointer(ptr.pPg, ptr.iCell, ptr.pSeg, &iOut, &bFound);
       ptr.pPg = 0;
     }
-    segmentPtrReset(&ptr);
+    segmentPtrReset(&ptr, 0);
   }
 
   *piPtr = iOut;
@@ -1658,7 +1667,7 @@ static int segmentPtrSeek(
        || lsmFsDbPageIsLast(pPtr->pSeg, pPtr->pPg)
   );
   if( pPtr->nCell==0 ){
-    segmentPtrReset(pPtr);
+    segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
   }else{
     iMin = 0;
     iMax = pPtr->nCell-1;
@@ -1716,7 +1725,7 @@ static int segmentPtrSeek(
               }
               pCsr->flags |= CURSOR_SEEK_EQ;
             }
-            segmentPtrReset(pPtr);
+            segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
             break;
           }
           case LSM_SEEK_LE:
@@ -1943,7 +1952,7 @@ static int seekInLevel(
             rtTopic(pPtr->eType), pPtr->pKey, pPtr->nKey, 
             pLvl->iSplitTopic, pLvl->pSplitKey, pLvl->nSplitKey
         );
-        if( res<0 ) segmentPtrReset(pPtr);
+        if( res<0 ) segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
       }
 
       if( aPtr[i].pKey ) bHit = 1;
@@ -2219,7 +2228,7 @@ static void mcursorFreeComponents(MultiCursor *pCsr){
 
   /* Reset the segment pointers */
   for(i=0; i<pCsr->nPtr; i++){
-    segmentPtrReset(&pCsr->aPtr[i]);
+    segmentPtrReset(&pCsr->aPtr[i], 0);
   }
 
   /* And the b-tree cursor, if any */
@@ -2874,7 +2883,7 @@ static int multiCursorEnd(MultiCursor *pCsr, int bLast){
       if( bHit==0 && rc==LSM_OK ){
         rc = segmentPtrEnd(pCsr, pPtr, 1);
       }else{
-        segmentPtrReset(pPtr);
+        segmentPtrReset(pPtr, LSM_SEGMENTPTR_FREE_THRESHOLD);
       }
     }else{
       int bLhs = (pPtr->pSeg==&pLvl->lhs);
@@ -2886,7 +2895,7 @@ static int multiCursorEnd(MultiCursor *pCsr, int bLast){
       }
       for(iRhs=0; iRhs<pLvl->nRight && rc==LSM_OK; iRhs++){
         if( bHit ){
-          segmentPtrReset(&pPtr[iRhs+1]);
+          segmentPtrReset(&pPtr[iRhs+1], LSM_SEGMENTPTR_FREE_THRESHOLD);
         }else{
           rc = sortedRhsFirst(pCsr, pLvl, &pPtr[iRhs+bLhs]);
         }
@@ -2969,7 +2978,7 @@ void lsmMCursorReset(MultiCursor *pCsr){
   lsmTreeCursorReset(pCsr->apTreeCsr[0]);
   lsmTreeCursorReset(pCsr->apTreeCsr[1]);
   for(i=0; i<pCsr->nPtr; i++){
-    segmentPtrReset(&pCsr->aPtr[i]);
+    segmentPtrReset(&pCsr->aPtr[i], LSM_SEGMENTPTR_FREE_THRESHOLD);
   }
   pCsr->key.nData = 0;
 }
@@ -6079,8 +6088,8 @@ static int assertPointersOk(
     }
   }
 
-  segmentPtrReset(&ptr1);
-  segmentPtrReset(&ptr2);
+  segmentPtrReset(&ptr1, 0);
+  segmentPtrReset(&ptr2, 0);
   return LSM_OK;
 }
 

diff --git a/manifest b/manifest
index 63fbff713ed36688aa91060bf3de42c5a53c3d13..81f884f340dc81bfab2e6bec0744950c4546b809 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C In\sthe\scommand-line\sshell,\sadd\sthe\s-quote\soption\sto\sstart\sup\sin\squote\smode.\nEnhance\sthe\s".mode"\scommand\sso\sthat\sit\sreports\sthe\scurrent\soutput\smode\sif\ngiven\sno\sarguments.
-D 2017-06-29T21:33:25.847
+C Avoid\sconstantly\sfreeing\sand\sreallocing\ssmall\sinternal\sbuffers\sassociated\swith\nLSM\scursors.\sInstead,\sallow\sthem\sto\spersist\sfor\sthe\slifetime\sof\sthe\scursor\sif\nthey\sare\sLSM_SEGMENTPTR_FREE_THRESHOLD\s(default\s1024)\sbytes\sor\ssmaller.
+D 2017-06-30T11:44:11.712
 F Makefile.in 081e48dfe7f995d57ce1a88ddf4d2917b4349158648a6cd45b42beae30de3a12
 F Makefile.linux-gcc 7bc79876b875010e8c8f9502eb935ca92aa3c434
 F Makefile.msc 4ebb1d257cac7fb1bcb4ba59278416d410ff1c4bf59447a9c37a415f3516056a
@@ -244,7 +244,7 @@ F ext/lsm1/lsm_main.c f52eada2910f8a57bd4cafcee39c6c375f6b7ed8
 F ext/lsm1/lsm_mem.c 4c51ea9fa285ee6e35301b33491642d071740a0a
 F ext/lsm1/lsm_mutex.c 378edf0a2b142b4f7640ee982df06d50b98788ea
 F ext/lsm1/lsm_shared.c 54cc3a5157c6abd77f7d3ae60708b9f7bf022b3c
-F ext/lsm1/lsm_sorted.c 4a9e3ffecda87b379ed757b59c9cbcd84a80b55c
+F ext/lsm1/lsm_sorted.c 62cc605a66cf8e0e6ab3593281c2476a787fc4b2013c618dd17568d18c730070
 F ext/lsm1/lsm_str.c 77ebdd5040ddf267a6f724d4c83132d2dce8a226
 F ext/lsm1/lsm_tree.c 5d9fb2bc58a1a70c75126bd8d7198f7b627e165b
 F ext/lsm1/lsm_unix.c 14aaebdd7a7e9abb57cc16890c8444b241de272bfc2303b68f6e6b984040dc1e
@@ -1628,7 +1628,7 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 7782c04e9b2c0e95b5ac2a38876c1a233becfd892140bc6844790d62aeaff4f7
-R fdaec3a4a9930118ae9822ddeb4d3259
-U drh
-Z c0bf63d58bf1bc98c2ecc9c2e3c0756c
+P 5e3f9ea5c4fad35fe02a12d59114e94ee00e0a09c1840c88908a4c282e2f4625
+R e4ed1fd49ca170fbcc3ace94e802f0dd
+U dan
+Z 88693dceee9c2741baead710728f55cc

diff --git a/manifest.uuid b/manifest.uuid
index 0ce32bc0f09d8b7b0b2dc505cb10e53387332d2c..ffbb56964a50ccfa4cbe5716f46d1bd36bf70a2a 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-5e3f9ea5c4fad35fe02a12d59114e94ee00e0a09c1840c88908a4c282e2f4625
\ No newline at end of file
+bacfe8cb3e4d3be736c6789b2ce55ef5603e5c7a289b05b37cae2203cd7f2290
\ No newline at end of file