Merge #7871: Manual block file pruning.

afffeea fixup! Add pruneblockchain RPC to enable manual block file pruning. (Russell Yanofsky)
1fc4ec7 Add pruneblockchain RPC to enable manual block file pruning. (mrbandrews)

5 files changed, 93 insertions, 11 deletions

diff --git a/src/init.cpp b/src/init.cpp
index 992ce8ebd..9ac69b7d3 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -351,9 +351,9 @@ std::string HelpMessage(HelpMessageMode mode)
 #ifndef WIN32
     strUsage += HelpMessageOpt("-pid=<file>", strprintf(_("Specify pid file (default: %s)"), BITCOIN_PID_FILENAME));
 #endif
-    strUsage += HelpMessageOpt("-prune=<n>", strprintf(_("Reduce storage requirements by pruning (deleting) old blocks. This mode is incompatible with -txindex and -rescan. "
+    strUsage += HelpMessageOpt("-prune=<n>", strprintf(_("Reduce storage requirements by enabling pruning (deleting) of old blocks. This allows the pruneblockchain RPC to be called to delete specific blocks, and enables automatic pruning of old blocks if a target size in MiB is provided. This mode is incompatible with -txindex and -rescan. "
             "Warning: Reverting this setting requires re-downloading the entire blockchain. "
-            "(default: 0 = disable pruning blocks, >%u = target size in MiB to use for block files)"), MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024));
+            "(default: 0 = disable pruning blocks, 1 = allow manual pruning via RPC, >%u = automatically prune block files to stay under the specified target size in MiB)"), MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024));
     strUsage += HelpMessageOpt("-reindex-chainstate", _("Rebuild chain state from the currently indexed blocks"));
     strUsage += HelpMessageOpt("-reindex", _("Rebuild chain state and block index from the blk*.dat files on disk"));
 #ifndef WIN32
@@ -936,12 +936,16 @@ bool AppInitParameterInteraction()
         nScriptCheckThreads = MAX_SCRIPTCHECK_THREADS;
 
     // block pruning; get the amount of disk space (in MiB) to allot for block & undo files
-    int64_t nSignedPruneTarget = GetArg("-prune", 0) * 1024 * 1024;
-    if (nSignedPruneTarget < 0) {
+    int64_t nPruneArg = GetArg("-prune", 0);
+    if (nPruneArg < 0) {
         return InitError(_("Prune cannot be configured with a negative value."));
     }
-    nPruneTarget = (uint64_t) nSignedPruneTarget;
-    if (nPruneTarget) {
+    nPruneTarget = (uint64_t) nPruneArg * 1024 * 1024;
+    if (nPruneArg == 1) {  // manual pruning: -prune=1
+        LogPrintf("Block pruning enabled.  Use RPC call pruneblockchain(height) to manually prune block and undo files.\n");
+        nPruneTarget = std::numeric_limits<uint64_t>::max();
+        fPruneMode = true;
+    } else if (nPruneTarget) {
         if (nPruneTarget < MIN_DISK_SPACE_FOR_BLOCK_FILES) {
             return InitError(strprintf(_("Prune configured below the minimum of %d MiB.  Please use a higher number."), MIN_DISK_SPACE_FOR_BLOCK_FILES / 1024 / 1024));
         }
diff --git a/src/rpc/blockchain.cpp b/src/rpc/blockchain.cpp
index 0b42c1d62..e828618a8 100644
--- a/src/rpc/blockchain.cpp
+++ b/src/rpc/blockchain.cpp
@@ -814,6 +814,46 @@ static bool GetUTXOStats(CCoinsView *view, CCoinsStats &stats)
     return true;
 }
 
+UniValue pruneblockchain(const JSONRPCRequest& request)
+{
+    if (request.fHelp || request.params.size() != 1)
+        throw runtime_error(
+            "pruneblockchain\n"
+            "\nArguments:\n"
+            "1. \"height\"       (numeric, required) The block height to prune up to. May be set to a discrete height, or to a unix timestamp to prune based on block time.\n");
+
+    if (!fPruneMode)
+        throw JSONRPCError(RPC_METHOD_NOT_FOUND, "Cannot prune blocks because node is not in prune mode.");
+
+    LOCK(cs_main);
+
+    int heightParam = request.params[0].get_int();
+    if (heightParam < 0)
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Negative block height.");
+
+    // Height value more than a billion is too high to be a block height, and
+    // too low to be a block time (corresponds to timestamp from Sep 2001).
+    if (heightParam > 1000000000) {
+        CBlockIndex* pindex = chainActive.FindLatestBefore(heightParam);
+        if (!pindex) {
+            throw JSONRPCError(RPC_INTERNAL_ERROR, "Could not find block before specified timestamp.");
+        }
+        heightParam = pindex->nHeight;
+    }
+
+    unsigned int height = (unsigned int) heightParam;
+    unsigned int chainHeight = (unsigned int) chainActive.Height();
+    if (chainHeight < Params().PruneAfterHeight())
+        throw JSONRPCError(RPC_INTERNAL_ERROR, "Blockchain is too short for pruning.");
+    else if (height > chainHeight)
+        throw JSONRPCError(RPC_INVALID_PARAMETER, "Blockchain is shorter than the attempted prune height.");
+    else if (height > chainHeight - MIN_BLOCKS_TO_KEEP)
+        LogPrint("rpc", "Attempt to prune blocks close to the tip.  Retaining the minimum number of blocks.");
+
+    PruneBlockFilesManual(height);
+    return NullUniValue;
+}
+
 UniValue gettxoutsetinfo(const JSONRPCRequest& request)
 {
     if (request.fHelp || request.params.size() != 0)
@@ -1384,6 +1424,7 @@ static const CRPCCommand commands[] =
     { "blockchain",         "getrawmempool",          &getrawmempool,          true,  {"verbose"} },
     { "blockchain",         "gettxout",               &gettxout,               true,  {"txid","n","include_mempool"} },
     { "blockchain",         "gettxoutsetinfo",        &gettxoutsetinfo,        true,  {} },
+    { "blockchain",         "pruneblockchain",        &pruneblockchain,        true,  {"height"} },
     { "blockchain",         "verifychain",            &verifychain,            true,  {"checklevel","nblocks"} },
 
     { "blockchain",         "preciousblock",          &preciousblock,          true,  {"blockhash"} },
diff --git a/src/rpc/client.cpp b/src/rpc/client.cpp
index 422d005f0..5d3c45845 100644
--- a/src/rpc/client.cpp
+++ b/src/rpc/client.cpp
@@ -103,6 +103,7 @@ static const CRPCConvertParam vRPCConvertParams[] =
     { "importmulti", 1, "options" },
     { "verifychain", 0, "checklevel" },
     { "verifychain", 1, "nblocks" },
+    { "pruneblockchain", 0, "height" },
     { "keypoolrefill", 0, "newsize" },
     { "getrawmempool", 0, "verbose" },
     { "estimatefee", 0, "nblocks" },
diff --git a/src/validation.cpp b/src/validation.cpp
index 37a4186e0..109a71fe7 100644
--- a/src/validation.cpp
+++ b/src/validation.cpp
@@ -185,7 +185,8 @@ enum FlushStateMode {
 };
 
 // See definition for documentation
-bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode);
+bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode, int nManualPruneHeight=0);
+void FindFilesToPruneManual(std::set<int>& setFilesToPrune, int nManualPruneHeight);
 
 bool IsFinalTx(const CTransaction &tx, int nBlockHeight, int64_t nBlockTime)
 {
@@ -1934,7 +1935,7 @@ bool ConnectBlock(const CBlock& block, CValidationState& state, CBlockIndex* pin
  * if they're too large, if it's been a while since the last write,
  * or always and in all cases if we're in prune mode and are deleting files.
  */
-bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode) {
+bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode, int nManualPruneHeight) {
     int64_t nMempoolUsage = mempool.DynamicMemoryUsage();
     const CChainParams& chainparams = Params();
     LOCK2(cs_main, cs_LastBlockFile);
@@ -1944,9 +1945,13 @@ bool static FlushStateToDisk(CValidationState &state, FlushStateMode mode) {
     std::set<int> setFilesToPrune;
     bool fFlushForPrune = false;
     try {
-    if (fPruneMode && fCheckForPruning && !fReindex) {
-        FindFilesToPrune(setFilesToPrune, chainparams.PruneAfterHeight());
-        fCheckForPruning = false;
+    if (fPruneMode && (fCheckForPruning || nManualPruneHeight > 0) && !fReindex) {
+        if (nManualPruneHeight > 0) {
+            FindFilesToPruneManual(setFilesToPrune, nManualPruneHeight);
+        } else {
+            FindFilesToPrune(setFilesToPrune, chainparams.PruneAfterHeight());
+            fCheckForPruning = false;
+        }
         if (!setFilesToPrune.empty()) {
             fFlushForPrune = true;
             if (!fHavePruned) {
@@ -3247,6 +3252,35 @@ void UnlinkPrunedFiles(std::set<int>& setFilesToPrune)
     }
 }
 
+/* Calculate the block/rev files to delete based on height specified by user with RPC command pruneblockchain */
+void FindFilesToPruneManual(std::set<int>& setFilesToPrune, int nManualPruneHeight)
+{
+    assert(fPruneMode && nManualPruneHeight > 0);
+
+    LOCK2(cs_main, cs_LastBlockFile);
+    if (chainActive.Tip() == NULL)
+        return;
+
+    // last block to prune is the lesser of (user-specified height, MIN_BLOCKS_TO_KEEP from the tip)
+    unsigned int nLastBlockWeCanPrune = min((unsigned)nManualPruneHeight, chainActive.Tip()->nHeight - MIN_BLOCKS_TO_KEEP);
+    int count=0;
+    for (int fileNumber = 0; fileNumber < nLastBlockFile; fileNumber++) {
+        if (vinfoBlockFile[fileNumber].nSize == 0 || vinfoBlockFile[fileNumber].nHeightLast > nLastBlockWeCanPrune)
+            continue;
+        PruneOneBlockFile(fileNumber);
+        setFilesToPrune.insert(fileNumber);
+        count++;
+    }
+    LogPrintf("Prune (Manual): prune_height=%d removed %d blk/rev pairs\n", nLastBlockWeCanPrune, count);
+}
+
+/* This function is called from the RPC code for pruneblockchain */
+void PruneBlockFilesManual(int nManualPruneHeight)
+{
+    CValidationState state;
+    FlushStateToDisk(state, FLUSH_STATE_NONE, nManualPruneHeight);
+}
+
 /* Calculate the block/rev files that should be deleted to remain under target*/
 void FindFilesToPrune(std::set<int>& setFilesToPrune, uint64_t nPruneAfterHeight)
 {
diff --git a/src/validation.h b/src/validation.h
index 631602a70..f5e76c7d3 100644
--- a/src/validation.h
+++ b/src/validation.h
@@ -309,6 +309,8 @@ CBlockIndex * InsertBlockIndex(uint256 hash);
 void FlushStateToDisk();
 /** Prune block files and flush state to disk. */
 void PruneAndFlush();
+/** Prune block files up to a given height */
+void PruneBlockFilesManual(int nPruneUpToHeight);
 
 /** (try to) add transaction to memory pool **/
 bool AcceptToMemoryPool(CTxMemPool& pool, CValidationState &state, const CTransactionRef &tx, bool fLimitFree,