From 0c9a35e2d5465efbfc5f8a240ba88430d5734fe9 Mon Sep 17 00:00:00 2001
From: Rusty Russell <rusty@rustcorp.com.au>
Date: Sat, 18 Oct 2025 08:51:47 +1030
Subject: [PATCH] plugins/sql: add payment_hash index to channelmoves table.

This significantly speeds up the query which bookkeeper often does:

		      "SELECT created_index"
		      " FROM channelmoves"
		      " WHERE payment_hash = X'%s'"
		      "   AND credit_msat = %"PRIu64
		      "   AND created_index <= %"PRIu64,

On large databases this scan is expensive, and a payment_hash index
cuts it down a great deal.  It does take longer to load the channelmoves
in the first place though (about 3x).

Before:
	$ while sleep 10; do wc -l /tmp/bkpr-progress; done
	169505 /tmp/bkpr-progress
	196010 /tmp/bkpr-progress
	219370 /tmp/bkpr-progress
	235671 /tmp/bkpr-progress
	244242 /tmp/bkpr-progress
	255362 /tmp/bkpr-progress
	265636 /tmp/bkpr-progress
	276966 /tmp/bkpr-progress
	284451 /tmp/bkpr-progress
	288836 /tmp/bkpr-progress
	296578 /tmp/bkpr-progress
	304571 /tmp/bkpr-progress

After:
	$ while sleep 10; do wc -l /tmp/bkpr-progress; done
	161421 /tmp/bkpr-progress
	238273 /tmp/bkpr-progress
	281185 /tmp/bkpr-progress
	305787 /tmp/bkpr-progress

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
Changelog-Changed: plugins: the sql plugin now keeps an index on `channelmoves` by `payment_hash`.
---
 plugins/sql.c        | 22 ++++++++++++++--------
 tests/test_plugin.py |  2 +-
 2 files changed, 15 insertions(+), 9 deletions(-)

diff --git a/plugins/sql.c b/plugins/sql.c
index 7b7e21bf4..a1c361da2 100644
--- a/plugins/sql.c
+++ b/plugins/sql.c
@@ -197,6 +197,10 @@ static const struct index indices[] = {
 		"channelmoves",
 		{ "account_id", NULL },
 	},
+	{
+		"channelmoves",
+		{ "payment_hash", NULL },
+	},
 };
 
 static enum fieldtype find_fieldtype(const jsmntok_t *name)
@@ -1757,20 +1761,22 @@ static const char *fmt_indexes(const tal_t *ctx, const char *table)
 	for (size_t i = 0; i < ARRAY_SIZE(indices); i++) {
 		if (!streq(indices[i].tablename, table))
 			continue;
-		/* FIXME: Handle multiple indices! */
-		assert(!ret);
+		if (!ret)
+			ret = tal_fmt(ctx, " indexed by ");
+		else
+			tal_append_fmt(&ret, ", also indexed by ");
 		BUILD_ASSERT(ARRAY_SIZE(indices[i].fields) == 2);
 		if (indices[i].fields[1])
-			ret = tal_fmt(tmpctx, "`%s` and `%s`",
-				      indices[i].fields[0],
-				      indices[i].fields[1]);
+			tal_append_fmt(&ret, "`%s` and `%s`",
+				       indices[i].fields[0],
+				       indices[i].fields[1]);
 		else
-			ret = tal_fmt(tmpctx, "`%s`",
-				      indices[i].fields[0]);
+			tal_append_fmt(&ret, "`%s`",
+				       indices[i].fields[0]);
 	}
 	if (!ret)
 		return "";
-	return tal_fmt(ctx, " indexed by %s", ret);
+	return ret;
 }
 
 static const char *json_prefix(const tal_t *ctx,
diff --git a/tests/test_plugin.py b/tests/test_plugin.py
index 82f832d42..48f4dcfef 100644
--- a/tests/test_plugin.py
+++ b/tests/test_plugin.py
@@ -3795,7 +3795,7 @@ def test_sql(node_factory, bitcoind):
                         {'name': 'extra_tags',
                          'type': 'string'}]},
         'channelmoves': {
-            'indices': [['account_id']],
+            'indices': [['account_id'], ['payment_hash']],
             'columns': [{'name': 'created_index',
                          'type': 'u64'},
                         {'name': 'account_id',