Improve the 409 Conflict detection, address DB concurrency.

The conflict now happens only if under the same withdraw
operation ID the wallet tries to select two different exchanges
or reserve public keys.

As of DB concurrency, there is now one thread (named "DB")
that should run all the database operations, in order to avoid
conflicts on the disk.  At this moment, and mostly to see where
the current implementation fails with regard to concurrent DB
access, not all the database operations were migrated into such thread.

1 files changed, 4 insertions, 0 deletions

diff --git a/sandbox/src/main/kotlin/tech/libeufin/sandbox/DB.kt b/sandbox/src/main/kotlin/tech/libeufin/sandbox/DB.kt
index f1fbe561..ef6d3704 100644
--- a/sandbox/src/main/kotlin/tech/libeufin/sandbox/DB.kt
+++ b/sandbox/src/main/kotlin/tech/libeufin/sandbox/DB.kt
@@ -422,6 +422,8 @@ object TalerWithdrawalsTable : LongIdTable() {
      * the payment arrived at the exchange's bank yet.
      */
     val transferDone = bool("transferDone").default(false)
+    val reservePub = text("reservePub").nullable()
+    val selectedExchangePayto = text("selectedExchangePayto").nullable()
 
 }
 class TalerWithdrawalEntity(id: EntityID<Long>) : LongEntity(id) {
@@ -429,6 +431,8 @@ class TalerWithdrawalEntity(id: EntityID<Long>) : LongEntity(id) {
     var wopid by TalerWithdrawalsTable.wopid
     var selectionDone by TalerWithdrawalsTable.selectionDone
     var transferDone by TalerWithdrawalsTable.transferDone
+    var reservePub by TalerWithdrawalsTable.reservePub
+    var selectedExchangePayto by TalerWithdrawalsTable.selectedExchangePayto
 }
 
 object BankAccountReportsTable : IntIdTable() {