From eb342c306d556dc5d58c2d90d76e96345dc5cb1c Mon Sep 17 00:00:00 2001
From: Kim van der Riet <kpvdr@apache.org>
Date: Tue, 26 Nov 2013 08:13:30 +0000
Subject: QPID-5357 "Linearstore: Empty file recycling not functional": Fix
 which implements the empty file check for trailing empty files.

git-svn-id: https://svn.apache.org/repos/asf/qpid/trunk@1545563 13f79535-47bb-0310-9956-ffa450edef68
---
 qpid/cpp/src/linearstore.cmake                              |  4 ++--
 .../src/qpid/linearstore/journal/LinearFileController.cpp   | 13 +++++++++++--
 .../cpp/src/qpid/linearstore/journal/LinearFileController.h |  1 +
 3 files changed, 14 insertions(+), 4 deletions(-)

(limited to 'qpid/cpp')

diff --git a/qpid/cpp/src/linearstore.cmake b/qpid/cpp/src/linearstore.cmake
index 2930ef9531..8568cdbb77 100644
--- a/qpid/cpp/src/linearstore.cmake
+++ b/qpid/cpp/src/linearstore.cmake
@@ -147,10 +147,10 @@ if (BUILD_LINEARSTORE)
     )
 
     if(NOT EXISTS ${CMAKE_CURRENT_BINARY_DIR}/db-inc.h)
-      message(STATUS "Including BDB from ${DB_INCLUDE_DIR}/db_cxx.h")
+      message(STATUS "Including BDB from ${DB_CXX_INCLUDE_DIR}/db_cxx.h")
         file(WRITE 
              ${CMAKE_CURRENT_BINARY_DIR}/db-inc.h
-             "#include <${DB_INCLUDE_DIR}/db_cxx.h>\n")
+             "#include <${DB_CXX_INCLUDE_DIR}/db_cxx.h>\n")
     endif()
 
     add_library (linearstoreutils SHARED
diff --git a/qpid/cpp/src/qpid/linearstore/journal/LinearFileController.cpp b/qpid/cpp/src/qpid/linearstore/journal/LinearFileController.cpp
index 99b7f0f381..aa0f6da0de 100644
--- a/qpid/cpp/src/qpid/linearstore/journal/LinearFileController.cpp
+++ b/qpid/cpp/src/qpid/linearstore/journal/LinearFileController.cpp
@@ -36,7 +36,8 @@ LinearFileController::LinearFileController(jcntl& jcntlRef) :
             emptyFilePoolPtr_(0),
             currentJournalFilePtr_(0),
             fileSeqCounter_("LinearFileController::fileSeqCounter", 0),
-            recordIdCounter_("LinearFileController::recordIdCounter", 0)
+            recordIdCounter_("LinearFileController::recordIdCounter", 0),
+            decrCounter_("LinearFileController::decrCounter", 0)
 {}
 
 LinearFileController::~LinearFileController() {}
@@ -106,7 +107,15 @@ uint32_t LinearFileController::incrEnqueuedRecordCount(const efpFileCount_t file
 uint32_t LinearFileController::decrEnqueuedRecordCount(const efpFileCount_t fileSeqNumber) {
     slock l(journalFileListMutex_);
     uint32_t r = find(fileSeqNumber)->decrEnqueuedRecordCount();
-//    purgeEmptyFilesToEfpNoLock();
+
+    // TODO: Re-evaluate after testing and profiling
+    // This is the first go at implementing auto-purge, which checks for all trailing empty files and recycles
+    // them back to the EFP. This version checks every 100 decrements using decrCounter_ (an action which releases
+    // records). We need to check this rather simple scheme works for outlying scenarios (large and tiny data
+    // records) without impacting performance or performing badly (leaving excessive empty files in the journals).
+    if (decrCounter_.increment() % 100ULL == 0ULL) {
+        purgeEmptyFilesToEfpNoLock();
+    }
     return r;
 }
 
diff --git a/qpid/cpp/src/qpid/linearstore/journal/LinearFileController.h b/qpid/cpp/src/qpid/linearstore/journal/LinearFileController.h
index 61226d3015..fa8327007a 100644
--- a/qpid/cpp/src/qpid/linearstore/journal/LinearFileController.h
+++ b/qpid/cpp/src/qpid/linearstore/journal/LinearFileController.h
@@ -47,6 +47,7 @@ protected:
     JournalFile* currentJournalFilePtr_;
     AtomicCounter<uint64_t> fileSeqCounter_;
     AtomicCounter<uint64_t> recordIdCounter_;
+    AtomicCounter<uint64_t> decrCounter_;
 
     JournalFileList_t journalFileList_;
     smutex journalFileListMutex_;
-- 
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