Merge #13033: Build txindex in parallel with validation

9b2704777c [doc] Include txindex changes in the release notes. (Jim Posen)
ed77dd6b30 [test] Simple unit test for TxIndex. (Jim Posen)
6d772a3d44 [rpc] Public interfaces to GetTransaction block until synced. (Jim Posen)
a03f804f2a [index] Move disk IO logic from GetTransaction to TxIndex::FindTx. (Jim Posen)
e0a3b80033 [validation] Replace tx index code in validation code with TxIndex. (Jim Posen)
8181db88f6 [init] Initialize and start TxIndex in init code. (Jim Posen)
f90c3a62f5 [index] TxIndex method to wait until caught up. (Jim Posen)
70d510d93c [index] Allow TxIndex sync thread to be interrupted. (Jim Posen)
94b4f8bbb9 [index] TxIndex initial sync thread. (Jim Posen)
34d68bf3a3 [index] Create new TxIndex class. (Jim Posen)
c88bcec93f [db] Migration for txindex data to new, separate database. (Jim Posen)
0cb8303241 [db] Create separate database for txindex. (Jim Posen)

Pull request description:

  I'm re-opening #11857 as a new pull request because the last one stopped loading for people

  -------------------------------

  This refactors the tx index code to be in it's own class and get built concurrently with validation code. The main benefit is decoupling and moving the txindex into a separate DB. The primary motivation is to lay the groundwork for other indexers that might be desired (such as the [compact filters](https://github.com/bitcoin/bips/pull/636)). The basic idea is that the TxIndex spins up its own thread, which first syncs the txindex to the current block index, then once in sync the BlockConnected ValidationInterface hook writes new blocks.

  ### DB changes

  At the suggestion of some other developers, the txindex has been split out into a separate database. A data migration runs at startup on any nodes with a legacy txindex. Currently the migration blocks node initialization until complete.

  ### Open questions

  - Should the migration of txindex data from the old DB to the new DB block in init or should it happen in a background thread? The downside to backgrounding it is that `getrawtransaction` would return an error message saying the txindex is syncing while the migration is running.

  ### Impact

  In a sample size n=1 test where I synced nodes from scratch, the average time [Index writing](https://github.com/bitcoin/bitcoin/blob/master/src/validation.cpp#L1903) was 3.36ms in master and 1.72ms in this branch. The average time between `UpdateTip` log lines for sequential blocks between 400,000 and IBD end on mainnet was 0.297204s in master and 0.286134s in this branch. Most likely this is just variance in IBD times, but I can try with some more trials if people want.

Tree-SHA512: 451fd7d95df89dfafceaa723cdf0f7b137615b531cf5c5035cfb54e9ccc2026cec5ac85edbcf71b7f4e2f102e36e9202b8b3a667e1504a9e1a9976ab1f0079c4

1 files changed, 27 insertions, 16 deletions

diff --git a/src/init.cpp b/src/init.cpp
index f403f90b0..eca3577f2 100644
--- a/src/init.cpp
+++ b/src/init.cpp
@@ -19,6 +19,7 @@
 #include <fs.h>
 #include <httpserver.h>
 #include <httprpc.h>
+#include <index/txindex.h>
 #include <key.h>
 #include <validation.h>
 #include <miner.h>
@@ -182,6 +183,9 @@ void Interrupt()
     InterruptMapPort();
     if (g_connman)
         g_connman->Interrupt();
+    if (g_txindex) {
+        g_txindex->Interrupt();
+    }
 }
 
 void Shutdown()
@@ -212,6 +216,9 @@ void Shutdown()
     if (g_connman) g_connman->Stop();
     peerLogic.reset();
     g_connman.reset();
+    if (g_txindex) {
+        g_txindex.reset();
+    }
 
     StopTorControl();
 
@@ -1414,9 +1421,10 @@ bool AppInitMain()
     int64_t nTotalCache = (gArgs.GetArg("-dbcache", nDefaultDbCache) << 20);
     nTotalCache = std::max(nTotalCache, nMinDbCache << 20); // total cache cannot be less than nMinDbCache
     nTotalCache = std::min(nTotalCache, nMaxDbCache << 20); // total cache cannot be greater than nMaxDbcache
-    int64_t nBlockTreeDBCache = nTotalCache / 8;
-    nBlockTreeDBCache = std::min(nBlockTreeDBCache, (gArgs.GetBoolArg("-txindex", DEFAULT_TXINDEX) ? nMaxBlockDBAndTxIndexCache : nMaxBlockDBCache) << 20);
+    int64_t nBlockTreeDBCache = std::min(nTotalCache / 8, nMaxBlockDBCache << 20);
     nTotalCache -= nBlockTreeDBCache;
+    int64_t nTxIndexCache = std::min(nTotalCache / 8, gArgs.GetBoolArg("-txindex", DEFAULT_TXINDEX) ? nMaxTxIndexCache << 20 : 0);
+    nTotalCache -= nTxIndexCache;
     int64_t nCoinDBCache = std::min(nTotalCache / 2, (nTotalCache / 4) + (1 << 23)); // use 25%-50% of the remainder for disk cache
     nCoinDBCache = std::min(nCoinDBCache, nMaxCoinsDBCache << 20); // cap total coins db cache
     nTotalCache -= nCoinDBCache;
@@ -1424,6 +1432,9 @@ bool AppInitMain()
     int64_t nMempoolSizeMax = gArgs.GetArg("-maxmempool", DEFAULT_MAX_MEMPOOL_SIZE) * 1000000;
     LogPrintf("Cache configuration:\n");
     LogPrintf("* Using %.1fMiB for block index database\n", nBlockTreeDBCache * (1.0 / 1024 / 1024));
+    if (gArgs.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
+        LogPrintf("* Using %.1fMiB for transaction index database\n", nTxIndexCache * (1.0 / 1024 / 1024));
+    }
     LogPrintf("* Using %.1fMiB for chain state database\n", nCoinDBCache * (1.0 / 1024 / 1024));
     LogPrintf("* Using %.1fMiB for in-memory UTXO set (plus up to %.1fMiB of unused mempool space)\n", nCoinCacheUsage * (1.0 / 1024 / 1024), nMempoolSizeMax * (1.0 / 1024 / 1024));
 
@@ -1457,9 +1468,8 @@ bool AppInitMain()
 
                 if (fRequestShutdown) break;
 
-                // LoadBlockIndex will load fTxIndex from the db, or set it if
-                // we're reindexing. It will also load fHavePruned if we've
-                // ever removed a block file from disk.
+                // LoadBlockIndex will load fHavePruned if we've ever removed a
+                // block file from disk.
                 // Note that it also sets fReindex based on the disk flag!
                 // From here on out fReindex and fReset mean something different!
                 if (!LoadBlockIndex(chainparams)) {
@@ -1473,12 +1483,6 @@ bool AppInitMain()
                     return InitError(_("Incorrect or no genesis block found. Wrong datadir for network?"));
                 }
 
-                // Check for changed -txindex state
-                if (fTxIndex != gArgs.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
-                    strLoadError = _("You need to rebuild the database using -reindex to change -txindex");
-                    break;
-                }
-
                 // Check for changed -prune state.  What we are concerned about is a user who has pruned blocks
                 // in the past, but is now trying to run unpruned.
                 if (fHavePruned && !fPruneMode) {
@@ -1608,10 +1612,17 @@ bool AppInitMain()
         ::feeEstimator.Read(est_filein);
     fFeeEstimatesInitialized = true;
 
-    // ********************************************************* Step 8: load wallet
+    // ********************************************************* Step 8: start indexers
+    if (gArgs.GetBoolArg("-txindex", DEFAULT_TXINDEX)) {
+        auto txindex_db = MakeUnique<TxIndexDB>(nTxIndexCache, false, fReindex);
+        g_txindex = MakeUnique<TxIndex>(std::move(txindex_db));
+        g_txindex->Start();
+    }
+
+    // ********************************************************* Step 9: load wallet
     if (!g_wallet_init_interface.Open()) return false;
 
-    // ********************************************************* Step 9: data directory maintenance
+    // ********************************************************* Step 10: data directory maintenance
 
     // if pruning, unset the service bit and perform the initial blockstore prune
     // after any wallet rescanning has taken place.
@@ -1633,7 +1644,7 @@ bool AppInitMain()
         nLocalServices = ServiceFlags(nLocalServices | NODE_WITNESS);
     }
 
-    // ********************************************************* Step 10: import blocks
+    // ********************************************************* Step 11: import blocks
 
     if (!CheckDiskSpace() && !CheckDiskSpace(0, true))
         return false;
@@ -1672,7 +1683,7 @@ bool AppInitMain()
         return false;
     }
 
-    // ********************************************************* Step 11: start node
+    // ********************************************************* Step 12: start node
 
     int chain_active_height;
 
@@ -1750,7 +1761,7 @@ bool AppInitMain()
         return false;
     }
 
-    // ********************************************************* Step 12: finished
+    // ********************************************************* Step 13: finished
 
     SetRPCWarmupFinished();
     uiInterface.InitMessage(_("Done loading"));