Add pgLsnRangeToWalSegmentList() to convert lsn range to wal segments.

src/postgres/interface.c

@@ -622,6 +622,66 @@ pgLsnToWalSegment(uint32_t timeline, uint64_t lsn, unsigned int walSegmentSize)
         strNewFmt("%08X%08X%08X", timeline, (unsigned int)(lsn >> 32), (unsigned int)(lsn & 0xFFFFFFFF) / walSegmentSize));
 }
 
+/**********************************************************************************************************************************/
+StringList *
+pgLsnRangeToWalSegmentList(
+    unsigned int pgVersion, uint32_t timeline, uint64_t lsnStart, uint64_t lsnStop, unsigned int walSegmentSize)
+{
+    FUNCTION_TEST_BEGIN();
+        FUNCTION_TEST_PARAM(UINT, pgVersion);
+        FUNCTION_TEST_PARAM(UINT, timeline);
+        FUNCTION_TEST_PARAM(UINT64, lsnStart);
+        FUNCTION_TEST_PARAM(UINT64, lsnStop);
+        FUNCTION_TEST_PARAM(UINT, walSegmentSize);
+    FUNCTION_TEST_END();
+
+    ASSERT(pgVersion != 0);
+    ASSERT(timeline != 0);
+    ASSERT(lsnStart <= lsnStop);
+    ASSERT(walSegmentSize != 0);
+    ASSERT(pgVersion > PG_VERSION_92 || walSegmentSize == PG_WAL_SEGMENT_SIZE_DEFAULT);
+
+    StringList *result = NULL;
+
+    MEM_CONTEXT_TEMP_BEGIN()
+    {
+        result = strLstNew();
+
+        // Skip the FF segment when PostgreSQL <= 9.2 (in this case segment size should always be 16MB)
+        bool skipFF = pgVersion <= PG_VERSION_92;
+
+        // Calculate the start and stop segments
+        unsigned int startMajor = (unsigned int)(lsnStart >> 32);
+        unsigned int startMinor = (unsigned int)(lsnStart & 0xFFFFFFFF) / walSegmentSize;
+
+        unsigned int stopMajor = (unsigned int)(lsnStop >> 32);
+        unsigned int stopMinor = (unsigned int)(lsnStop & 0xFFFFFFFF) / walSegmentSize;
+
+        unsigned int minorPerMajor = 0xFFFFFFFF / walSegmentSize;
+
+        // Create list
+        strLstAdd(result, strNewFmt("%08X%08X%08X", timeline, startMajor, startMinor));
+
+        while (!(startMajor == stopMajor && startMinor == stopMinor))
+        {
+            startMinor++;
+
+            if ((skipFF && startMinor == 0xFF) || (!skipFF && startMinor > minorPerMajor))
+            {
+                startMajor++;
+                startMinor = 0;
+            }
+
+            strLstAdd(result, strNewFmt("%08X%08X%08X", timeline, startMajor, startMinor));
+        }
+
+        strLstMove(result, MEM_CONTEXT_OLD());
+    }
+    MEM_CONTEXT_TEMP_END();
+
+    FUNCTION_TEST_RETURN(result);
+}
+
 /**********************************************************************************************************************************/
 const String *
 pgLsnName(unsigned int pgVersion)

src/postgres/interface.h

@@ -132,6 +132,10 @@ String *pgLsnToStr(uint64_t lsn);
 // Convert a timeline and lsn to a wal segment
 String *pgLsnToWalSegment(uint32_t timeline, uint64_t lsn, unsigned int walSegmentSize);
 
+// Convert a timeline and lsn range to a list of wal segments
+StringList *pgLsnRangeToWalSegmentList(
+    unsigned int pgVersion, uint32_t timeline, uint64_t lsnStart, uint64_t lsnStop, unsigned int walSegmentSize);
+
 // Get name used for lsn in functions (this was changed in PostgreSQL 10 for consistency since lots of names were changing)
 const String *pgLsnName(unsigned int pgVersion);
 

test/src/module/postgres/interfaceTest.c

@@ -102,7 +102,7 @@ testRun(void)
     }
 
     // *****************************************************************************************************************************
-    if (testBegin("pgLsnFromStr(), pgLsnToStr(), and pgLsnToWalSegment()"))
+    if (testBegin("pgLsnFromStr(), pgLsnToStr(), pgLsnToWalSegment(), and pgLsnRangeToWalSegmentList()"))
     {
         TEST_RESULT_UINT(pgLsnFromStr(STRDEF("1/1")), 0x0000000100000001, "lsn to string");
         TEST_RESULT_UINT(pgLsnFromStr(STRDEF("ffffffff/ffffffff")), 0xFFFFFFFFFFFFFFFF, "lsn to string");
@@ -115,6 +115,42 @@ testRun(void)
         TEST_RESULT_STR_Z(pgLsnToWalSegment(1, 0xFFFFFFFFAAAAAAAA, 0x1000000), "00000001FFFFFFFF000000AA", "lsn to wal segment");
         TEST_RESULT_STR_Z(pgLsnToWalSegment(1, 0xFFFFFFFFAAAAAAAA, 0x40000000), "00000001FFFFFFFF00000002", "lsn to wal segment");
         TEST_RESULT_STR_Z(pgLsnToWalSegment(1, 0xFFFFFFFF40000000, 0x40000000), "00000001FFFFFFFF00000001", "lsn to wal segment");
+
+        TEST_RESULT_STR_Z(
+            strLstJoin(
+                pgLsnRangeToWalSegmentList(
+                    PG_VERSION_92, 1, pgLsnFromStr(STRDEF("1/60")), pgLsnFromStr(STRDEF("1/60")), 16 * 1024 * 1024),
+                ", "),
+            "000000010000000100000000", "get single");
+        TEST_RESULT_STR_Z(
+            strLstJoin(
+                pgLsnRangeToWalSegmentList(
+                    PG_VERSION_92, 2, pgLsnFromStr(STRDEF("1/FD000000")), pgLsnFromStr(STRDEF("2/1000000")), 16 * 1024 * 1024),
+                ", "),
+            "0000000200000001000000FD, 0000000200000001000000FE, 000000020000000200000000, 000000020000000200000001",
+            "get range <= 9.2");
+        TEST_RESULT_STR_Z(
+            strLstJoin(
+                pgLsnRangeToWalSegmentList(
+                    PG_VERSION_93, 2, pgLsnFromStr(STRDEF("1/FD000000")), pgLsnFromStr(STRDEF("2/60")), 16 * 1024 * 1024),
+                ", "),
+            "0000000200000001000000FD, 0000000200000001000000FE, 0000000200000001000000FF, 000000020000000200000000",
+            "get range > 9.2");
+        TEST_RESULT_STR_Z(
+            strLstJoin(
+                pgLsnRangeToWalSegmentList(
+                    PG_VERSION_11, 2, pgLsnFromStr(STRDEF("A/800")), pgLsnFromStr(STRDEF("B/C0000000")), 1024 * 1024 * 1024),
+                ", "),
+            "000000020000000A00000000, 000000020000000A00000001, 000000020000000A00000002, 000000020000000A00000003"
+                ", 000000020000000B00000000, 000000020000000B00000001, 000000020000000B00000002, 000000020000000B00000003",
+            "get range >= 11/1GB");
+        TEST_RESULT_STR_Z(
+            strLstJoin(
+                pgLsnRangeToWalSegmentList(
+                    PG_VERSION_11, 3, pgLsnFromStr(STRDEF("7/FFEFFFFF")), pgLsnFromStr(STRDEF("8/001AAAAA")), 1024 * 1024),
+                ", "),
+            "000000030000000700000FFE, 000000030000000700000FFF, 000000030000000800000000, 000000030000000800000001",
+            "get range >= 11/1MB");
     }
 
     // *****************************************************************************************************************************