Add the SQLITE_DIRECT_OVERFLOW_READ compile time option.

FossilOrigin-Name: 2ab14a846727857175eac7961b7338c4d3b417ca

diff --git a/manifest b/manifest
index 7f9710268d3ce8c7a56247dd8803bd42c6a3bce3..b38c1ac5fb3d496b16afcf839363c0b5595e30a3 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Change\sthe\sANALYZE\scommand\sso\sthat\sit\sno\slonger\stried\sto\sdelete\sunused\nsqlite_stat2\sand\ssqlite_stat3\stables.\s\sChange\sthe\sDROP\sTABLE\scommand\sso\nthat\sit\sis\sable\sto\sdrop\sthose\stables.
-D 2011-10-07T23:52:25.818
+C Add\sthe\sSQLITE_DIRECT_OVERFLOW_READ\scompile\stime\soption.
+D 2011-10-08T14:57:07.518
 F Makefile.arm-wince-mingw32ce-gcc d6df77f1f48d690bd73162294bbba7f59507c72f
 F Makefile.in a162fe39e249b8ed4a65ee947c30152786cfe897
 F Makefile.linux-gcc 91d710bdc4998cb015f39edf3cb314ec4f4d7e23
@@ -124,7 +124,7 @@ F src/auth.c 523da7fb4979469955d822ff9298352d6b31de34
 F src/backup.c 4fd4440c8f81339d8eb8e5d2df54b68d79e94f2f
 F src/bitvec.c af50f1c8c0ff54d6bdb7a80e2fceca5a93670bef
 F src/btmutex.c 976f45a12e37293e32cae0281b15a21d48a8aaa7
-F src/btree.c 77b09c69d4849a90361e6fe5db36d167f20600c0
+F src/btree.c b53e009bccb4cfcbcde074f586f0c1c6712a0e12
 F src/btree.h f5d775cd6cfc7ac32a2535b70e8d2af48ef5f2ce
 F src/btreeInt.h 67978c014fa4f7cc874032dd3aacadd8db656bc3
 F src/build.c 119937b0ae1ff4dcec8fdea53771acc95bafca51
@@ -201,7 +201,7 @@ F src/test_async.c 0612a752896fad42d55c3999a5122af10dcf22ad
 F src/test_autoext.c 30e7bd98ab6d70a62bb9ba572e4c7df347fe645e
 F src/test_backup.c c129c91127e9b46e335715ae2e75756e25ba27de
 F src/test_btree.c 47cd771250f09cdc6e12dda5bc71bc0b3abc96e2
-F src/test_config.c 6b1b69da02eb9a19330d8c2c33403c6eafbc3416
+F src/test_config.c baf4eda361adc7444bd452d352999fea351fe256
 F src/test_demovfs.c 20a4975127993f4959890016ae9ce5535a880094
 F src/test_devsym.c e7498904e72ba7491d142d5c83b476c4e76993bc
 F src/test_func.c cbdec5cededa0761daedde5baf06004a9bf416b5
@@ -335,7 +335,7 @@ F test/colname.test 08948a4809d22817e0e5de89c7c0a8bd90cb551b
 F test/conflict.test cabc41f7616675df71b4fddabca3bd5d9221915a
 F test/corrupt.test 4aabd06cff3fe759e3e658bcc17b71789710665e
 F test/corrupt2.test 9c0ab4becd50e9050bc1ebb8675456a4e5587bf0
-F test/corrupt3.test e3006aaf579d2ed7f1b94bf4cc695d3c784fa5af
+F test/corrupt3.test 889d7cdb811800303aa722d7813fe8a4299cf726
 F test/corrupt4.test b963f9e01e0f92d15c76fb0747876fd4b96dc30a
 F test/corrupt5.test c23da7bfb20917cc7fdbb13ee25c7cc4e9fffeff
 F test/corrupt6.test 4e4161aef1f30b9f34582bb4142334b7f47eacae
@@ -611,13 +611,13 @@ F test/notnull.test cc7c78340328e6112a13c3e311a9ab3127114347
 F test/null.test a8b09b8ed87852742343b33441a9240022108993
 F test/openv2.test 0d3040974bf402e19b7df4b783e447289d7ab394
 F test/oserror.test 50417780d0e0d7cd23cf12a8277bb44024765df3
-F test/pager1.test c8f202a460ba6a1cd7a36888042ca471220bb42d
+F test/pager1.test 1b630b3248c7d28862fe9e190cfe52234b502504
 F test/pager2.test 745b911dde3d1f24ae0870bd433dfa83d7c658c1
 F test/pager3.test 3856d9c80839be0668efee1b74811b1b7f7fc95f
 F test/pagerfault.test 452f2cc23e3bfcfa935f4442aec1da4fe1dc0442
 F test/pagerfault2.test 1f79ea40d1133b2683a2f811b00f2399f7ec2401
 F test/pagerfault3.test f16e2efcb5fc9996d1356f7cbc44c998318ae1d7
-F test/pageropt.test 8146bf448cf09e87bb1867c2217b921fb5857806
+F test/pageropt.test 9191867ed19a2b3db6c42d1b36b6fbc657cd1ab0
 F test/pagesize.test 1dd51367e752e742f58e861e65ed7390603827a0
 F test/pcache.test 065aa286e722ab24f2e51792c1f093bf60656b16
 F test/pcache2.test a83efe2dec0d392f814bfc998def1d1833942025
@@ -966,7 +966,7 @@ F tool/symbols.sh caaf6ccc7300fd43353318b44524853e222557d5
 F tool/tostr.awk e75472c2f98dd76e06b8c9c1367f4ab07e122d06
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
 F tool/warnings.sh fbc018d67fd7395f440c28f33ef0f94420226381
-P d4f95b3b6e9f4a4072606af5daa17ea7c645382e
-R 4fe120270d0591d545e8a0d8aa07746c
-U drh
-Z 90bf796c032cc3a71272ed4f53de20b0
+P 589f3f5652e3674d3203f8bd32784a46b5ed530c
+R babeecaade74546f993a47787aab0e8e
+U dan
+Z de8a70093b027b61b524c5ce14f74c38

diff --git a/manifest.uuid b/manifest.uuid
index 0be934d7e19167b84110722a56ca2c8028fb2df9..a11f91efcc65ee0a1ccf3a8b93754c35b2dba36f 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-589f3f5652e3674d3203f8bd32784a46b5ed530c
\ No newline at end of file
+2ab14a846727857175eac7961b7338c4d3b417ca
\ No newline at end of file

diff --git a/src/btree.c b/src/btree.c
index 7e6e02f144772ee3e2aa330942576675d680cfcb..72d61cc2681b5bb9667a8ee3c10891b1b01519aa 100644 (file)
--- a/src/btree.c
+++ b/src/btree.c
@@ -3938,21 +3938,55 @@ static int accessPayload(
         /* Need to read this page properly. It contains some of the
         ** range of data that is being read (eOp==0) or written (eOp!=0).
         */
-        DbPage *pDbPage;
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+        sqlite3_file *fd;
+#endif
         int a = amt;
-        rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage);
-        if( rc==SQLITE_OK ){
-          aPayload = sqlite3PagerGetData(pDbPage);
-          nextPage = get4byte(aPayload);
-          if( a + offset > ovflSize ){
-            a = ovflSize - offset;
+        if( a + offset > ovflSize ){
+          a = ovflSize - offset;
+        }
+
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+        /* If all the following are true:
+        **
+        **   1) this is a read operation, and 
+        **   2) data is required from the start of this overflow page, and
+        **   3) the database is file-backed, and
+        **   4) there is no open write-transaction, and
+        **   5) the database is not a WAL database,
+        **
+        ** then data can be read directly from the database file into the
+        ** output buffer, bypassing the page-cache altogether. This speeds
+        ** up loading large records that span many overflow pages.
+        */
+        if( eOp==0                                             /* (1) */
+         && offset==0                                          /* (2) */
+         && pBt->inTransaction==TRANS_READ                     /* (4) */
+         && (fd = sqlite3PagerFile(pBt->pPager))->pMethods     /* (3) */
+         && pBt->pPage1->aData[19]==0x01                       /* (5) */
+        ){
+          u8 aSave[4];
+          u8 *aWrite = &pBuf[-4];
+          memcpy(aSave, aWrite, 4);
+          rc = sqlite3OsRead(fd, aWrite, a+4, pBt->pageSize * (nextPage-1));
+          nextPage = get4byte(aWrite);
+          memcpy(aWrite, aSave, 4);
+        }else
+#endif
+
+        {
+          DbPage *pDbPage;
+          rc = sqlite3PagerGet(pBt->pPager, nextPage, &pDbPage);
+          if( rc==SQLITE_OK ){
+            aPayload = sqlite3PagerGetData(pDbPage);
+            nextPage = get4byte(aPayload);
+            rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
+            sqlite3PagerUnref(pDbPage);
+            offset = 0;
           }
-          rc = copyPayload(&aPayload[offset+4], pBuf, a, eOp, pDbPage);
-          sqlite3PagerUnref(pDbPage);
-          offset = 0;
-          amt -= a;
-          pBuf += a;
         }
+        amt -= a;
+        pBuf += a;
       }
     }
   }

diff --git a/src/test_config.c b/src/test_config.c
index 4c4dfa3d809f327456058a50b199621c9c61c15b..b0efe232470c2ec718e487d44c730f206abd8294 100644 (file)
--- a/src/test_config.c
+++ b/src/test_config.c
@@ -55,6 +55,12 @@ static void set_options(Tcl_Interp *interp){
   Tcl_SetVar2(interp, "sqlite_options", "debug", "0", TCL_GLOBAL_ONLY);
 #endif
 
+#ifdef SQLITE_DIRECT_OVERFLOW_READ
+  Tcl_SetVar2(interp, "sqlite_options", "direct_read", "1", TCL_GLOBAL_ONLY);
+#else
+  Tcl_SetVar2(interp, "sqlite_options", "direct_read", "0", TCL_GLOBAL_ONLY);
+#endif
+
 #ifdef SQLITE_DISABLE_DIRSYNC
   Tcl_SetVar2(interp, "sqlite_options", "dirsync", "0", TCL_GLOBAL_ONLY);
 #else

diff --git a/test/corrupt3.test b/test/corrupt3.test
index fba3ba791a7645d4423cffccfdff417d51c14b73..a3827227b7f4346a21fd9650e0f4fe6cf209e3ec 100644 (file)
--- a/test/corrupt3.test
+++ b/test/corrupt3.test
@@ -25,7 +25,7 @@ do_not_use_codec
 
 # We must have the page_size pragma for these tests to work.
 #
-ifcapable !pager_pragmas {
+ifcapable !pager_pragmas||direct_read {
   finish_test
   return
 }

diff --git a/test/pager1.test b/test/pager1.test
index bed7d736cd5b75cd8828f795d30b808f0e73f610..0226fe49b298871747bb4d6b8942b9ffa8b34c64 100644 (file)
--- a/test/pager1.test
+++ b/test/pager1.test
@@ -1766,6 +1766,10 @@ do_multiclient_test tn {
 #   + Page 0,
 #   + A page with a page number greater than (2^31-1).
 #
+# These tests will not work if SQLITE_DIRECT_OVERFLOW_READ is defined. In
+# that case IO errors are sometimes reported instead of SQLITE_CORRUPT.
+#
+ifcapable !direct_read {
 do_test pager1-18.1 {
   faultsim_delete_and_reopen
   db func a_string a_string
@@ -1841,6 +1845,7 @@ do_test pager1-18.6 {
   sqlite3 db test.db
   catchsql { SELECT length(x) FROM t1 }
 } {1 {database disk image is malformed}}
+}
 
 do_test pager1-19.1 {
   sqlite3 db ""

diff --git a/test/pageropt.test b/test/pageropt.test
index 1c634f6443c81ab34489d6425f4a31cb7018a60b..82311965a5f7decb3795646d78622f6364b3f435 100644 (file)
--- a/test/pageropt.test
+++ b/test/pageropt.test
@@ -17,7 +17,7 @@
 set testdir [file dirname $argv0]
 source $testdir/tester.tcl
 
-ifcapable {!pager_pragmas||secure_delete} {
+ifcapable {!pager_pragmas||secure_delete||direct_read} {
   finish_test
   return
 }