Comment clarifications in wal.c.

FossilOrigin-Name: a029be10172e2e6a2ef4e3eb2ea1bd0ca85b16ed

manifest

@@ -1,8 +1,8 @@
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-C Remove\san\sunreachable\stest\sfrom\swal.c.
-D 2010-05-17T20:16:50
+C Comment\sclarifications\sin\swal.c.
+D 2010-05-18T12:56:50
 F Makefile.arm-wince-mingw32ce-gcc fcd5e9cd67fe88836360bb4f9ef4cb7f8e2fb5a0
 F Makefile.in a5cad1f8f3e021356bfcc6c77dc16f6f1952bbc3
 F Makefile.linux-gcc d53183f4aa6a9192d249731c90dbdffbd2c68654
@@ -227,7 +227,7 @@ F src/vdbeblob.c 5327132a42a91e8b7acfb60b9d2c3b1c5c863e0e
 F src/vdbemem.c 2a82f455f6ca6f78b59fb312f96054c04ae0ead1
 F src/vdbetrace.c 864cef96919323482ebd9986f2132435115e9cc2
 F src/vtab.c a0f8a40274e4261696ef57aa806de2776ab72cda
-F src/wal.c 431efda4869ddb638b24766a7d18d991c24d7517
+F src/wal.c 5bdd0270bd6eedf019df41ead35353d5b346cb66
 F src/wal.h 434f76f51225bb614e43ccb6bd2341541ba6a06e
 F src/walker.c 3112bb3afe1d85dc52317cb1d752055e9a781f8f
 F src/where.c 75fee9e255b62f773fcadd1d1f25b6f63ac7a356
@@ -816,14 +816,14 @@ F tool/speedtest2.tcl ee2149167303ba8e95af97873c575c3e0fab58ff
 F tool/speedtest8.c 2902c46588c40b55661e471d7a86e4dd71a18224
 F tool/speedtest8inst1.c 293327bc76823f473684d589a8160bde1f52c14e
 F tool/vdbe-compress.tcl d70ea6d8a19e3571d7ab8c9b75cba86d1173ff0f
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manifest.uuid

@@ -1 +1 @@
-7162c45673d1068d1fda55a70207a3cd77575502
+a029be10172e2e6a2ef4e3eb2ea1bd0ca85b16ed

src/wal.c

@@ -22,7 +22,7 @@
 ** WRITE-AHEAD LOG (WAL) FILE FORMAT
 **
 ** A wal file consists of a header followed by zero or more "frames".
-** The header is 12 bytes in size and consists of the following three
+** The file header is 12 bytes in size and consists of the following three
 ** big-endian 32-bit unsigned integer values:
 **
 **     0: Database page size,
@@ -44,9 +44,9 @@
 /* 
 ** WAL-INDEX FILE FORMAT
 **
-** The wal-index file consists of a 32-byte header region, followed by an 
+** The wal-index consists of a 32-byte header region, followed by an 
 ** 8-byte region that contains no useful data (used to apply byte-range locks
-** to), followed by the data region. 
+** in some implementations), followed by the data region. 
 **
 ** The contents of both the header and data region are specified in terms
 ** of 1, 2 and 4 byte unsigned integers. All integers are stored in 
@@ -57,19 +57,13 @@
 ** mapping from database page number to the set of locations in the wal
 ** file that contain versions of the database page. When a database 
 ** client needs to read a page of data, it first queries the wal-index
-** file to determine if the required version of the page is stored in
+** to determine if the required version of the page is stored in
 ** the wal. If so, the page is read from the wal. If not, the page is
 ** read from the database file.
 **
 ** Whenever a transaction is appended to the wal or a checkpoint transfers
 ** data from the wal into the database file, the wal-index is 
 ** updated accordingly.
-**
-** The fields in the wal-index file header are described in the comment 
-** directly above the definition of struct WalIndexHdr (see below). 
-** Immediately following the fields in the WalIndexHdr structure is
-** an 8 byte checksum based on the contents of the header. This field is
-** not the same as the iCheck1 and iCheck2 fields of the WalIndexHdr.
 */
 
 /* Object declarations */
@@ -1397,7 +1391,7 @@ int sqlite3WalFrames(
   }
   assert( pWal->pWiData==0 );
 
-  /* Append data to the log summary. It is not necessary to lock the 
+  /* Append data to the wal-index. It is not necessary to lock the 
   ** wal-index to do this as the RESERVED lock held on the db file
   ** guarantees that there are no other writers, and no data that may
   ** be in use by existing readers is being overwritten.