db: infrastructure to initialize indexes.

We set next_<tablename>_<indexname>_index as separate var fields.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>

wallet/db.c

@@ -67,6 +67,9 @@ static void migrate_fill_in_channel_type(struct lightningd *ld,
 static void migrate_normalize_invstr(struct lightningd *ld,
 				     struct db *db);
 
+static void migrate_initialize_wait_indexes(struct lightningd *ld,
+					    struct db *db);
+
 /* Do not reorder or remove elements from this array, it is used to
  * migrate existing databases from a previous state, based on the
  * string indices */
@@ -959,6 +962,7 @@ static struct migration dbmigrations[] = {
     {SQL("CREATE TABLE runes (id BIGSERIAL, rune TEXT, PRIMARY KEY (id));"), NULL},
     {SQL("CREATE TABLE runes_blacklist (start_index BIGINT, end_index BIGINT);"), NULL},
     {SQL("ALTER TABLE channels ADD ignore_fee_limits INTEGER DEFAULT 0;"), NULL},
+    {NULL, migrate_initialize_wait_indexes},
 };
 
 /**
@@ -1393,6 +1397,18 @@ migrate_inflight_last_tx_to_psbt(struct lightningd *ld, struct db *db)
 	tal_free(stmt);
 }
 
+void load_indexes(struct db *db, struct indexes *indexes)
+{
+	for (size_t s = 0; s < NUM_WAIT_SUBSYSTEM; s++) {
+		for (size_t i = 0; i < NUM_WAIT_INDEX; i++) {
+			const char *fname = tal_fmt(tmpctx, "last_%s_%s_index",
+						    wait_subsystem_name(s),
+						    wait_index_name(i));
+			indexes[s].i[i] = db_get_intvar(db, fname, 0);
+		}
+	}
+}
+
 /* We're moving everything over to PSBTs from tx's, particularly our last_tx's
  * which are commitment transactions for channels.
  * This migration loads all of the last_tx's and 're-formats' them into psbts,
@@ -1635,6 +1651,24 @@ static void migrate_fill_in_channel_type(struct lightningd *ld,
 	tal_free(stmt);
 }
 
+static void migrate_initialize_wait_indexes(struct lightningd *ld,
+					    struct db *db)
+{
+	struct db_stmt *stmt;
+	bool res;
+
+	/* "invoices.id" serves as the created_index.  It's never 0. */
+	stmt = db_prepare_v2(db, SQL("SELECT MAX(id) FROM invoices;"));
+	db_query_prepared(stmt);
+	res = db_step(stmt);
+	assert(res);
+
+	if (!db_col_is_null(stmt, "MAX(id)"))
+		db_set_intvar(db, "last_invoice_created_index",
+			      db_col_u64(stmt, "MAX(id)"));
+	tal_free(stmt);
+}
+
 static void complain_unfixed(struct lightningd *ld,
 			     enum channel_state state,
 			     u64 id,

wallet/db.h

@@ -3,6 +3,7 @@
 #include "config.h"
 
 struct ext_key;
+struct indexes;
 struct lightningd;
 struct db_stmt;
 struct db;
@@ -22,4 +23,7 @@ struct db;
 struct db *db_setup(const tal_t *ctx, struct lightningd *ld,
 		    const struct ext_key *bip32_base);
 
+/* We store last wait indices in our var table. */
+void load_indexes(struct db *db, struct indexes *indexes);
+
 #endif /* LIGHTNING_WALLET_DB_H */

wallet/test/run-db.c

@@ -62,6 +62,12 @@ u8 *towire_hsmd_get_channel_basepoints(const tal_t *ctx UNNEEDED, const struct n
 /* Generated stub for towire_hsmd_get_output_scriptpubkey */
 u8 *towire_hsmd_get_output_scriptpubkey(const tal_t *ctx UNNEEDED, u64 channel_id UNNEEDED, const struct node_id *peer_id UNNEEDED, const struct pubkey *commitment_point UNNEEDED)
 { fprintf(stderr, "towire_hsmd_get_output_scriptpubkey called!\n"); abort(); }
+/* Generated stub for wait_index_name */
+const char *wait_index_name(enum wait_index index UNNEEDED)
+{ fprintf(stderr, "wait_index_name called!\n"); abort(); }
+/* Generated stub for wait_subsystem_name */
+const char *wait_subsystem_name(enum wait_subsystem subsystem UNNEEDED)
+{ fprintf(stderr, "wait_subsystem_name called!\n"); abort(); }
 /* Generated stub for wire_sync_read */
 u8 *wire_sync_read(const tal_t *ctx UNNEEDED, int fd UNNEEDED)
 { fprintf(stderr, "wire_sync_read called!\n"); abort(); }

wallet/test/run-wallet.c

@@ -856,6 +856,12 @@ void try_reconnect(const tal_t *ctx UNNEEDED,
 		   struct peer *peer UNNEEDED,
 		   const struct wireaddr_internal *addrhint UNNEEDED)
 { fprintf(stderr, "try_reconnect called!\n"); abort(); }
+/* Generated stub for wait_index_name */
+const char *wait_index_name(enum wait_index index UNNEEDED)
+{ fprintf(stderr, "wait_index_name called!\n"); abort(); }
+/* Generated stub for wait_subsystem_name */
+const char *wait_subsystem_name(enum wait_subsystem subsystem UNNEEDED)
+{ fprintf(stderr, "wait_subsystem_name called!\n"); abort(); }
 /* Generated stub for watch_txid */
 struct txwatch *watch_txid(const tal_t *ctx UNNEEDED,
 			   struct chain_topology *topo UNNEEDED,

wallet/wallet.c

@@ -114,6 +114,7 @@ struct wallet *wallet_new(struct lightningd *ld, struct timers *timers)
 	db_begin_transaction(wallet->db);
 	wallet->invoices = invoices_new(wallet, wallet, timers);
 	outpointfilters_init(wallet);
+	load_indexes(wallet->db, ld->indexes);
 	db_commit_transaction(wallet->db);
 	return wallet;
 }