From 2ff65699401b9cd67e5c246cbdf0e174a7004931 Mon Sep 17 00:00:00 2001
From: drh <>
Date: Sun, 19 Mar 2023 21:48:55 +0000
Subject: [PATCH] Increase the size of ref-count values in the pager layer to
 64-bits, to avoid any reasonable possiblity of overflowing the counters.
 There is a performance and memory penality for this.
 [forum:/forumpost/b741f15a35|Forum post b741f15a35].

FossilOrigin-Name: 6c5d99a813e8498c2ea91383ac8886a43eaf47023919c03900e893640c03778d
---
 manifest      | 16 ++++++++--------
 manifest.uuid |  2 +-
 src/pcache.c  |  8 ++++----
 src/pcache.h  |  6 +++---
 4 files changed, 16 insertions(+), 16 deletions(-)

diff --git a/manifest b/manifest
index a56838f0a0..138c8790b9 100644
--- a/manifest
+++ b/manifest
@@ -1,5 +1,5 @@
-C Avoid\sa\sbuffer\soverread\sin\sfts3\sthat\scould\soccur\swhen\sprocessing\sa\scorrupt\srecord.
-D 2023-03-18T16:12:27.555
+C Increase\sthe\ssize\sof\sref-count\svalues\sin\sthe\spager\slayer\sto\s64-bits,\sto\savoid\nany\sreasonable\spossiblity\sof\soverflowing\sthe\scounters.\nThere\sis\sa\sperformance\sand\smemory\spenality\sfor\sthis.\n[forum:/forumpost/b741f15a35|Forum\spost\sb741f15a35].
+D 2023-03-19T21:48:55.585
 F .fossil-settings/empty-dirs dbb81e8fc0401ac46a1491ab34a7f2c7c0452f2f06b54ebb845d024ca8283ef1
 F .fossil-settings/ignore-glob 35175cdfcf539b2318cb04a9901442804be81cd677d8b889fcc9149c21f239ea
 F LICENSE.md df5091916dbb40e6e9686186587125e1b2ff51f022cc334e886c19a0e9982724
@@ -615,8 +615,8 @@ F src/os_win.h 7b073010f1451abe501be30d12f6bc599824944a
 F src/pager.c 39af8ff7c73a991f61f4d1e3a6f8f98b1c8e29144723507822774cac5e6ee0b5
 F src/pager.h f82e9844166e1585f5786837ddc7709966138ced17f568c16af7ccf946c2baa3
 F src/parse.y 424e49ed8fc6c907920db9be5a13a75ed43811e1ea8dd21b0fa9ef97f083dc6b
-F src/pcache.c f4268f7f73c6a3db12ce22fd25bc68dc42315d19599414ab1207d7cf32f79197
-F src/pcache.h 4f87acd914cef5016fae3030343540d75f5b85a1877eed1a2a19b9f284248586
+F src/pcache.c 842410539b544e12d5fccfcf29890782f46a58f227a77bc0bd76243799662c0c
+F src/pcache.h 1497ce1b823cf00094bb0cf3bac37b345937e6f910890c626b16512316d3abf5
 F src/pcache1.c dee95e3cd2b61e6512dc814c5ab76d5eb36f0bfc9441dbb4260fccc0d12bbddc
 F src/pragma.c c0c6e0735436e0e9e8d490f82959ddc9475d438e9f808a51953a4d43e30cea51
 F src/pragma.h e690a356c18e98414d2e870ea791c1be1545a714ba623719deb63f7f226d8bb7
@@ -2051,8 +2051,8 @@ F vsixtest/vsixtest.tcl 6a9a6ab600c25a91a7acc6293828957a386a8a93
 F vsixtest/vsixtest.vcxproj.data 2ed517e100c66dc455b492e1a33350c1b20fbcdc
 F vsixtest/vsixtest.vcxproj.filters 37e51ffedcdb064aad6ff33b6148725226cd608e
 F vsixtest/vsixtest_TemporaryKey.pfx e5b1b036facdb453873e7084e1cae9102ccc67a0
-P 0910b1925e97f7ae4dae86894c9e2f54273c85115e19d0d9bff1280ffee35eed
-R 0669622949fcc9c4cc476c1d0c95dee1
-U dan
-Z 7914734e12c594e04b43e5b8d992dc23
+P 02ac2297abee6af64c8df230b42b07f21cff4565d7e315860b2396a7c0c556ca
+R 786303851e34199f284746d4fa5c1e0a
+U drh
+Z 90a20a841f2fa0f322839e6c9c925028
 # Remove this line to create a well-formed Fossil manifest.
diff --git a/manifest.uuid b/manifest.uuid
index fea3d9d247..a0d05a322e 100644
--- a/manifest.uuid
+++ b/manifest.uuid
@@ -1 +1 @@
-02ac2297abee6af64c8df230b42b07f21cff4565d7e315860b2396a7c0c556ca
\ No newline at end of file
+6c5d99a813e8498c2ea91383ac8886a43eaf47023919c03900e893640c03778d
\ No newline at end of file
diff --git a/src/pcache.c b/src/pcache.c
index 0407e06b2f..153628dc9a 100644
--- a/src/pcache.c
+++ b/src/pcache.c
@@ -41,7 +41,7 @@
 struct PCache {
   PgHdr *pDirty, *pDirtyTail;         /* List of dirty pages in LRU order */
   PgHdr *pSynced;                     /* Last synced page in dirty page list */
-  int nRefSum;                        /* Sum of ref counts over all pages */
+  i64 nRefSum;                        /* Sum of ref counts over all pages */
   int szCache;                        /* Configured cache size */
   int szSpill;                        /* Size before spilling occurs */
   int szPage;                         /* Size of every page in this cache */
@@ -71,7 +71,7 @@ struct PCache {
     unsigned char *a;
     int j;
     pPg = (PgHdr*)pLower->pExtra;
-    printf("%3d: nRef %2d flgs %02x data ", i, pPg->nRef, pPg->flags);
+    printf("%3lld: nRef %2d flgs %02x data ", i, pPg->nRef, pPg->flags);
     a = (unsigned char *)pLower->pBuf;
     for(j=0; j<12; j++) printf("%02x", a[j]);
     printf(" ptr %p\n", pPg);
@@ -815,14 +815,14 @@ PgHdr *sqlite3PcacheDirtyList(PCache *pCache){
 ** This is not the total number of pages referenced, but the sum of the
 ** reference count for all pages.
 */
-int sqlite3PcacheRefCount(PCache *pCache){
+i64 sqlite3PcacheRefCount(PCache *pCache){
   return pCache->nRefSum;
 }
 
 /*
 ** Return the number of references to the page supplied as an argument.
 */
-int sqlite3PcachePageRefcount(PgHdr *p){
+i64 sqlite3PcachePageRefcount(PgHdr *p){
   return p->nRef;
 }
 
diff --git a/src/pcache.h b/src/pcache.h
index eb55396afa..f945dab1a4 100644
--- a/src/pcache.h
+++ b/src/pcache.h
@@ -40,7 +40,7 @@ struct PgHdr {
   ** private to pcache.c and should not be accessed by other modules.
   ** pCache is grouped with the public elements for efficiency.
   */
-  i16 nRef;                      /* Number of users of this page */
+  i64 nRef;                      /* Number of users of this page */
   PgHdr *pDirtyNext;             /* Next element in list of dirty pages */
   PgHdr *pDirtyPrev;             /* Previous element in list of dirty pages */
                           /* NB: pDirtyNext and pDirtyPrev are undefined if the
@@ -121,12 +121,12 @@ void sqlite3PcacheClearSyncFlags(PCache *);
 void sqlite3PcacheClear(PCache*);
 
 /* Return the total number of outstanding page references */
-int sqlite3PcacheRefCount(PCache*);
+i64 sqlite3PcacheRefCount(PCache*);
 
 /* Increment the reference count of an existing page */
 void sqlite3PcacheRef(PgHdr*);
 
-int sqlite3PcachePageRefcount(PgHdr*);
+i64 sqlite3PcachePageRefcount(PgHdr*);
 
 /* Return the total number of pages stored in the cache */
 int sqlite3PcachePagecount(PCache*);