taler-typescript-core

commit 540cd68e6ef2d56559d91657ecde3b789a441119
parent f6b59b8b96fcdd4d87fb1e76f32f6b03dcb506be
Author: Florian Dold <dold@taler.net>
Date:   Thu,  6 Aug 2026 19:02:40 +0200

wallet: look up denomination families once per exchange update

An exchange has a handful of families but lists a denomination per family and
rotation period, so querying per denomination was a query per row of /keys.

Issue: https://bugs.taler.net/n/11334

Diffstat:
M
packages/taler-wallet-core/src/exchanges.ts
 | 
86
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++---------------------

1 file changed, 63 insertions(+), 23 deletions(-)
diff --git a/packages/taler-wallet-core/src/exchanges.ts b/packages/taler-wallet-core/src/exchanges.ts
@@ -952,6 +952,27 @@ async function checkExchangeEntryOutdated(
 }
 
 /**
+ * Key identifying a denomination family, for looking one up without a query
+ * per denomination.  Mirrors the unique index the DB layer has on these
+ * columns; amounts are canonical strings, so comparing them as text is what
+ * the query would do anyway.
+ *
+ * Joined on a character none of the components can contain, so that two
+ * different tuples cannot spell the same key.
+ */
+function denomFamilyParamsKey(p: WalletDenomFamilyParams): string {
+  return [
+    p.exchangeBaseUrl,
+    p.exchangeMasterPub,
+    p.value,
+    p.feeWithdraw,
+    p.feeDeposit,
+    p.feeRefresh,
+    p.feeRefund,
+  ].join("\u0000");
+}
+
+/**
  * Timestamp (in seconds) to ask the exchange to cherry-pick /keys by, or
  * undefined when the whole response should be downloaded.
  *
@@ -2143,33 +2164,54 @@ export async function updateExchangeFromUrlHandler(
 
     logger.trace("updating denominations in database");
 
+    // One lookup for all of them: an exchange has a handful of families but
+    // its /keys lists a denomination per family and rotation period, so a
+    // query per denomination is a query per row of the response.
+    const familySerialByParams = new Map<string, number>();
+    for (const fam of await tx.getDenominationFamiliesByExchange(
+      exchangeBaseUrl,
+    )) {
+      checkDbInvariant(
+        typeof fam.denominationFamilySerial === "number",
+        "denominationFamilySerial",
+      );
+      familySerialByParams.set(
+        denomFamilyParamsKey(fam.familyParams),
+        fam.denominationFamilySerial,
+      );
+    }
+
     for (const currentDenom of denomInfos) {
-      // FIXME: Check if we really already need the denomination.
-      let fpRec: WalletDenominationFamily | undefined =
-        await tx.getDenominationFamilyByParams({
-          exchangeBaseUrl: currentDenom.exchangeBaseUrl,
-          exchangeMasterPub: currentDenom.exchangeMasterPub,
-          value: currentDenom.value,
-          feeWithdraw: currentDenom.feeWithdraw,
-          feeDeposit: currentDenom.feeDeposit,
-          feeRefresh: currentDenom.feeRefresh,
-          feeRefund: currentDenom.feeRefund,
-        });
+      const familyParams: WalletDenomFamilyParams = {
+        exchangeBaseUrl: currentDenom.exchangeBaseUrl,
+        exchangeMasterPub: currentDenom.exchangeMasterPub,
+        value: currentDenom.value,
+        feeWithdraw: currentDenom.feeWithdraw,
+        feeDeposit: currentDenom.feeDeposit,
+        feeRefresh: currentDenom.feeRefresh,
+        feeRefund: currentDenom.feeRefund,
+      };
+      let fpRec: WalletDenominationFamily | undefined = undefined;
+      const knownSerial = familySerialByParams.get(
+        denomFamilyParamsKey(familyParams),
+      );
+      if (knownSerial != null) {
+        fpRec = { familyParams, denominationFamilySerial: knownSerial };
+      }
       let denominationFamilySerial;
       if (fpRec == null) {
-        const fp: WalletDenomFamilyParams = {
-          exchangeBaseUrl: exchangeBaseUrl,
-          exchangeMasterPub: keysInfo.master_public_key,
-          feeDeposit: currentDenom.feeDeposit,
-          feeRefresh: currentDenom.feeRefresh,
-          feeRefund: currentDenom.feeRefund,
-          feeWithdraw: currentDenom.feeWithdraw,
-          value: currentDenom.value,
-        };
         fpRec = {
-          familyParams: fp,
+          familyParams,
         };
         denominationFamilySerial = await tx.upsertDenominationFamily(fpRec);
+        checkDbInvariant(
+          typeof denominationFamilySerial === "number",
+          "denominationFamilySerial",
+        );
+        familySerialByParams.set(
+          denomFamilyParamsKey(familyParams),
+          denominationFamilySerial,
+        );
       } else {
         denominationFamilySerial = fpRec.denominationFamilySerial;
       }
@@ -2179,8 +2221,6 @@ export async function updateExchangeFromUrlHandler(
         "denominationFamilySerial",
       );
 
-      // First, find denom family
-
       const denomRec: WalletDenomination = {
         currency: keysInfo.currency,
         denominationFamilySerial,