Merge the mutex-free PRNG change into this branch.

FossilOrigin-Name: 81e626f4a44be75425cf916ec61b6b36df0907ebac4adbf6786f87ad4f3a0674

diff --git a/manifest b/manifest
index e89604258e36a2a0bc8b4aa9ab269c5484e4bd64..4fafda0823d426b86aec1bb1bea0c869d1104743 100644 (file)
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Merge\slatest\sbegin-concurrent\schanges\sinto\sthis\sbranch.
-D 2018-11-26T07:34:33.644
+C Merge\sthe\smutex-free\sPRNG\schange\sinto\sthis\sbranch.
+D 2018-11-30T16:26:39.800
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F Makefile.in b730006b54c990461d864c5387f2e6f13aadb0236804555fb010ed6865a5f058
@@ -465,7 +465,7 @@ F src/delete.c cec65c0e74be7492cafba1b77580732b0b1a41a4dbc4ac70909ac44b65b2a20b
 F src/expr.c 9aacc0b72348ba90010b672dcbbbe2fa56e1182043bc917a3a147b2bc57a5497
 F src/fault.c 460f3e55994363812d9d60844b2a6de88826e007
 F src/fkey.c 972a4ba14296bef2303a0abbad1e3d82bc3c61f9e6ce4e8e9528bdee68748812
-F src/func.c 7c288b4ce309b5a8b8473514b88e1f8e69a80134509a8c0db8e39c858e367e7f
+F src/func.c 8efa2c813b3f6a831a070311b5bcbc97993b79cbcd274bdb49bde56ccd3d37bc
 F src/global.c 9bf034fd560bdd514715170ed8460bb7f823cec113f0569ef3f18a20c7ccd128
 F src/hash.c 931ec82d7e070654a8facb42549bbb3a25720171d73ba94c3d3160580d01ef1f
 F src/hash.h ab34c5c54a9e9de2e790b24349ba5aab3dbb4fd4
@@ -474,7 +474,7 @@ F src/in-operator.md 10cd8f4bcd225a32518407c2fb2484089112fd71
 F src/insert.c 6b81aae27b196925d8ff78824f4bbd435d6a40cd38dc324685e21735bb402109
 F src/legacy.c 134ab3e3fae00a0f67a5187981d6935b24b337bcf0f4b3e5c9fa5763da95bf4e
 F src/loadext.c 448eab53ecdb566a1259ee2d45ebff9c0bc4a2cf393774488775c33e4fbe89bf
-F src/main.c 47b8f0411812b3dd7c41fddf09420638aabfb838c6134de0ec5c18df381ecd28
+F src/main.c b23c7b1eeca05ee3af56dacdc0efdf61484dc17194c82233fb98b42ee8e807b8
 F src/malloc.c 07295435093ce354c6d9063ac05a2eeae28bd251d2e63c48b3d67c12c76f7e18
 F src/mem0.c 6a55ebe57c46ca1a7d98da93aaa07f99f1059645
 F src/mem1.c c12a42539b1ba105e3707d0e628ad70e611040d8f5e38cf942cee30c867083de
@@ -507,15 +507,15 @@ F src/pragma.c a2eab23fbf7c70c28f3a22629de2662d052c22853649430be302b910719574de
 F src/pragma.h 7003ea8e45e5da0a7cd6d35846214f9ae9ecf5be66b268415ceea5855324af11
 F src/prepare.c f81f8d707e583192c28fea0b2e19385415b7d188123b23f49b038076408d7a69
 F src/printf.c 0f1177cf1dd4d7827bf64d840768514ec76409abecaca9e8b577dbd065150381
-F src/random.c 80f5d666f23feb3e6665a6ce04c7197212a88384
+F src/random.c f27af4099afaea7284ade5c206224dcfdb2334cfd119d018b470d46356b3f27d
 F src/resolve.c bc8c79e56439b111e7d9415e44940951f7087e9466c3a9d664558ef0faf31073
 F src/rowset.c d977b011993aaea002cab3e0bb2ce50cf346000dff94e944d547b989f4b1fe93
-F src/select.c 61e867a906f140b73baf4ce7a201ad6dcba30820969f5618ee40e9a0d32c6f5f
+F src/select.c e1cad752987c476a9d1d053682558caec048ea799ef7ba1b6e38e2266451010d
 F src/shell.c.in 6a9d8a56700d136addc14d1cd25863b8112e5c12e1877f373750bda476ff6314
 F src/sqlite.h.in 41dfd60cf62d4f8756991517c1a9d2ff4977ca04f7798c10b0c16dcf884cbc7e
 F src/sqlite3.rc 5121c9e10c3964d5755191c80dd1180c122fc3a8
 F src/sqlite3ext.h 960f1b86c3610fa23cb6a267572a97dcf286e77aa0dd3b9b23292ffaa1ea8683
-F src/sqliteInt.h b9f89d79c047df09c1efe2dfe054512cf956780af468daef9d368b319dc68aa7
+F src/sqliteInt.h ca2d5f030547a1677a74bce26338ca70ebd6747b7d500a9edc00146c61ff2376
 F src/sqliteLimit.h 1513bfb7b20378aa0041e7022d04acb73525de35b80b252f1b83fedb4de6a76b
 F src/status.c 46e7aec11f79dad50965a5ca5fa9de009f7d6bde08be2156f1538a0a296d4d0e
 F src/table.c b46ad567748f24a326d9de40e5b9659f96ffff34
@@ -592,7 +592,7 @@ F src/vdbesort.c 90aad5a92608f2dd771c96749beabdb562c9d881131a860a7a5bccf66dc3be7
 F src/vdbetrace.c 79d6dbbc479267b255a7de8080eee6e729928a0ef93ed9b0bfa5618875b48392
 F src/vtab.c 70188a745dc4e57d26e942681ff4b2912b7c8249ad5de3f60f0677b4337bcfaa
 F src/vxworks.h d2988f4e5a61a4dfe82c6524dd3d6e4f2ce3cdb9
-F src/wal.c 41de67424237a3dd097a093057ba454ccfef26c452f6263fecd5591a15dd5a9a
+F src/wal.c f53ac2b6ec6f23960471b4402632b8276d8b80c1ac31a28ea08500c56a9cc5c9
 F src/wal.h f325a5856b669f5ba449157485915816103857c8574efc746ac55eba3335c5e0
 F src/walker.c fb94aadc9099ff9c6506d0a8b88d51266005bcaa265403f3d7caf732a562eb66
 F src/where.c 3818e8a736a05d2cb194e64399af707e367fbcc5c251d785804d02eaf121288e
@@ -1791,7 +1791,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 6f3dd9809fdef7d6195f1f93428a662d5a8c01dba9815daa22d1b94059a2eb43 28a615a2e0f48b0fee3eaf7841ff902e069fa6c221df6ad9a57b8709c88561fb
-R c73a7474a8ba36fb4e79620530d56018
+P 76608f750ab13c0a165def9672759fee43cf4e9895df3bfa21765e08358b07a0
+Q +8b1fc4b9f3e743bffcfbbb8e26991240441778e10512fb502b8eaec460184296
+R 05d3a3eaadb134c59c94e4d5941647d0
 U dan
-Z 4a9121244def783d11e1880a226f98cc
+Z 45ce6d06a747e646527aeb46f6440480

diff --git a/manifest.uuid b/manifest.uuid
index 04bacb7327fe4dd8e7c840a052356af7c4030602..ade3e7b765ae014a2b977b1994914682be452b83 100644 (file)
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-76608f750ab13c0a165def9672759fee43cf4e9895df3bfa21765e08358b07a0
\ No newline at end of file
+81e626f4a44be75425cf916ec61b6b36df0907ebac4adbf6786f87ad4f3a0674
\ No newline at end of file

diff --git a/src/func.c b/src/func.c
index 0504a8f0266e8e5433a15fe03b96b00589f33df8..d8233835a2f68c767dd223771f44aec667e5bc80 100644 (file)
--- a/src/func.c
+++ b/src/func.c
@@ -485,8 +485,9 @@ static void randomFunc(
   sqlite3_value **NotUsed2
 ){
   sqlite_int64 r;
+  sqlite3 *db = sqlite3_context_db_handle(context);
   UNUSED_PARAMETER2(NotUsed, NotUsed2);
-  sqlite3_randomness(sizeof(r), &r);
+  sqlite3FastRandomness(&db->sPrng, sizeof(r), &r);
   if( r<0 ){
     /* We need to prevent a random number of 0x8000000000000000 
     ** (or -9223372036854775808) since when you do abs() of that
@@ -512,6 +513,7 @@ static void randomBlob(
 ){
   int n;
   unsigned char *p;
+  sqlite3 *db = sqlite3_context_db_handle(context);
   assert( argc==1 );
   UNUSED_PARAMETER(argc);
   n = sqlite3_value_int(argv[0]);
@@ -520,7 +522,7 @@ static void randomBlob(
   }
   p = contextMalloc(context, n);
   if( p ){
-    sqlite3_randomness(n, p);
+    sqlite3FastRandomness(&db->sPrng, n, p);
     sqlite3_result_blob(context, (char*)p, n, sqlite3_free);
   }
 }

diff --git a/src/main.c b/src/main.c
index 19831abfc7f84bf0240464f5476c4965c4391a87..38b056d93b58afbde5a398da7f27b54c5f112c1a 100644 (file)
--- a/src/main.c
+++ b/src/main.c
@@ -3023,7 +3023,7 @@ static int openDatabase(
   db->magic = SQLITE_MAGIC_BUSY;
   db->aDb = db->aDbStatic;
   db->lookaside.bDisable = 1;
-
+  sqlite3FastPrngInit(&db->sPrng);
   assert( sizeof(db->aLimit)==sizeof(aHardLimit) );
   memcpy(db->aLimit, aHardLimit, sizeof(db->aLimit));
   db->aLimit[SQLITE_LIMIT_WORKER_THREADS] = SQLITE_DEFAULT_WORKER_THREADS;

diff --git a/src/random.c b/src/random.c
index d4ae77c4355e8248fa8bab8548ea5f7962622b71..dd971ab655f1cd438fbe4dae4ea9a2297db0f678 100644 (file)
--- a/src/random.c
+++ b/src/random.c
@@ -106,6 +106,28 @@ void sqlite3_randomness(int N, void *pBuf){
   sqlite3_mutex_leave(mutex);
 }
 
+/*
+** Initialize a fast PRNG.  A Fast PRNG is called "fast" because it does
+** not need a mutex to operate, though it does use a mutex to initialize.
+** The quality of the randomness is not as good as the global PRNG.
+*/
+void sqlite3FastPrngInit(FastPrng *pPrng){
+  sqlite3_randomness(sizeof(*pPrng), pPrng);
+  pPrng->x |= 1;
+}
+
+/*
+** Generate N bytes of pseudo-randomness using a FastPrng
+*/
+void sqlite3FastRandomness(FastPrng *pPrng, int N, void *P){
+  unsigned char *pOut = (unsigned char*)P;
+  while( N-->0 ){
+    pPrng->x = ((pPrng->x)>>1) ^ ((1+~((pPrng->x)&1)) & 0xd0000001);
+    pPrng->y = (pPrng->y)*1103515245 + 12345;
+    *(pOut++) = (pPrng->x ^ pPrng->y) & 0xff;
+  }
+}
+
 #ifndef SQLITE_UNTESTABLE
 /*
 ** For testing purposes, we sometimes want to preserve the state of

diff --git a/src/select.c b/src/select.c
index c60ff270017733f3f7fa77153a0f0471c4b77ac8..5cd16307855591aab7462649e6412235d2f76e12 100644 (file)
--- a/src/select.c
+++ b/src/select.c
@@ -1993,7 +1993,7 @@ int sqlite3ColumnsFromExprList(
         if( zName[j]==':' ) nName = j;
       }
       zName = sqlite3MPrintf(db, "%.*z:%u", nName, zName, ++cnt);
-      if( cnt>3 ) sqlite3_randomness(sizeof(cnt), &cnt);
+      if( cnt>3 ) sqlite3FastRandomness(&db->sPrng, sizeof(cnt), &cnt);
     }
     pCol->zName = zName;
     sqlite3ColumnPropertiesFromName(0, pCol);

diff --git a/src/sqliteInt.h b/src/sqliteInt.h
index 12a9f38867b88d1010d0f984531de13e609a1404..410cc74c52681454a6a3cf886e90c51f5e6ebbc2 100644 (file)
--- a/src/sqliteInt.h
+++ b/src/sqliteInt.h
@@ -1089,6 +1089,7 @@ typedef struct Parse Parse;
 typedef struct PreUpdate PreUpdate;
 typedef struct PrintfArguments PrintfArguments;
 typedef struct RenameToken RenameToken;
+typedef struct FastPrng FastPrng;
 typedef struct RowSet RowSet;
 typedef struct Savepoint Savepoint;
 typedef struct Select Select;
@@ -1189,6 +1190,14 @@ typedef int VList;
 # define SQLITE_DEFAULT_WAL_SYNCHRONOUS SQLITE_DEFAULT_SYNCHRONOUS
 #endif
 
+/*
+** State of a simple PRNG used for the per-connection and per-pager
+** pseudo-random number generators.
+*/
+struct FastPrng {
+  unsigned int x, y;
+};
+
 /*
 ** Each database file to be accessed by the system is an instance
 ** of the following structure.  There are normally two of these structures
@@ -1398,6 +1407,7 @@ struct sqlite3 {
   u8 nSqlExec;                  /* Number of pending OP_SqlExec opcodes */
   int nextPagesize;             /* Pagesize after VACUUM if >0 */
   u32 magic;                    /* Magic number for detect library misuse */
+  FastPrng sPrng;               /* State of the per-connection PRNG */
   int nChange;                  /* Value returned by sqlite3_changes() */
   int nTotalChange;             /* Value returned by sqlite3_total_changes() */
   int aLimit[SQLITE_N_LIMIT];   /* Limits */
@@ -3997,6 +4007,8 @@ Vdbe *sqlite3GetVdbe(Parse*);
 void sqlite3PrngSaveState(void);
 void sqlite3PrngRestoreState(void);
 #endif
+void sqlite3FastPrngInit(FastPrng*);
+void sqlite3FastRandomness(FastPrng*, int N, void *P);
 void sqlite3RollbackAll(sqlite3*,int);
 void sqlite3CodeVerifySchema(Parse*, int);
 void sqlite3CodeVerifyNamedSchema(Parse*, const char *zDb);

diff --git a/src/wal.c b/src/wal.c
index 031389ea6f5d867c2eb44b66e192d64dcf2f4fb0..c67bd9dcac703ca24261758f33072056c426920c 100644 (file)
--- a/src/wal.c
+++ b/src/wal.c
@@ -474,6 +474,7 @@ struct Wal {
   u32 nPriorFrame;           /* For sqlite3WalInfo() */
   const char *zWalName;      /* Name of WAL file */
   u32 nCkpt;                 /* Checkpoint sequence counter in the wal-header */
+  FastPrng sPrng;            /* Random number generator */
 #ifdef SQLITE_DEBUG
   u8 lockError;              /* True if a locking error has occurred */
 #endif
@@ -1380,6 +1381,7 @@ int sqlite3WalOpen(
   pRet->syncHeader = 1;
   pRet->padToSectorBoundary = 1;
   pRet->exclusiveMode = (bNoShm ? WAL_HEAPMEMORY_MODE: WAL_NORMAL_MODE);
+  sqlite3FastPrngInit(&pRet->sPrng);
 
   /* Open file handle on the write-ahead log file. */
   flags = (SQLITE_OPEN_READWRITE|SQLITE_OPEN_CREATE|SQLITE_OPEN_WAL);
@@ -1926,7 +1928,7 @@ static int walCheckpoint(
       rc = SQLITE_BUSY;
     }else if( eMode>=SQLITE_CHECKPOINT_RESTART ){
       u32 salt1;
-      sqlite3_randomness(4, &salt1);
+      sqlite3FastRandomness(&pWal->sPrng, 4, &salt1);
       assert( pInfo->nBackfill==pWal->hdr.mxFrame );
       rc = walBusyLock(pWal, xBusy, pBusyArg, WAL_READ_LOCK(1), WAL_NREADER-1);
       if( rc==SQLITE_OK ){
@@ -3373,7 +3375,7 @@ static int walRestartLog(Wal *pWal){
     assert( pInfo->nBackfill==pWal->hdr.mxFrame );
     if( pInfo->nBackfill>0 ){
       u32 salt1;
-      sqlite3_randomness(4, &salt1);
+      sqlite3FastRandomness(&pWal->sPrng, 4, &salt1);
       rc = walLockExclusive(pWal, WAL_READ_LOCK(1), WAL_NREADER-1);
       if( rc==SQLITE_OK ){
         /* If all readers are using WAL_READ_LOCK(0) (in other words if no
@@ -3589,7 +3591,7 @@ int sqlite3WalFrames(
     sqlite3Put4byte(&aWalHdr[4], WAL_MAX_VERSION);
     sqlite3Put4byte(&aWalHdr[8], szPage);
     sqlite3Put4byte(&aWalHdr[12], pWal->nCkpt);
-    if( pWal->nCkpt==0 ) sqlite3_randomness(8, pWal->hdr.aSalt);
+    if( pWal->nCkpt==0 ) sqlite3FastRandomness(&pWal->sPrng, 8, pWal->hdr.aSalt);
     memcpy(&aWalHdr[16], pWal->hdr.aSalt, 8);
     walChecksumBytes(1, aWalHdr, WAL_HDRSIZE-2*4, 0, aCksum);
     sqlite3Put4byte(&aWalHdr[24], aCksum[0]);