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Fix read records #132

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merged 7 commits into from
Nov 6, 2024
Merged

Fix read records #132

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8f46d5d
fix read-records in transfer
yito88 Oct 28, 2024
96b6a84
fix scan-records for transfer-append
yito88 Oct 28, 2024
40f5416
fix to handle an exception for each record
yito88 Oct 29, 2024
a6766a0
fix tests
yito88 Oct 31, 2024
000a11d
fix retry num
yito88 Oct 31, 2024
188794e
seq exec read txs
yito88 Oct 31, 2024
0a0b749
fix for append
yito88 Nov 2, 2024
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34 changes: 18 additions & 16 deletions scalardb/src/scalardb/transfer.clj
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Original file line number Diff line number Diff line change
Expand Up @@ -125,37 +125,39 @@
(assoc op :type :fail :error {:results results})))))

(defn- read-record
"Read a record with a transaction. If read fails, an exception is thrown."
[tx storage i]
;; Need Storage API to read the transaction metadata
(let [tx-result (.get tx (prepare-get i))
result (.get storage (prepare-get i))]
"Read and update the specified record with a transaction"
[test id]
(let [tx (scalar/start-transaction test)
tx-result (.get tx (prepare-get id))
;; Need Storage API to read the transaction metadata
result (.get @(:storage test) (prepare-get id))]
;; Put the same balance to check conflicts with in-flight transactions
(->> (calc-new-balance tx-result 0)
(prepare-put i)
(prepare-put id)
(.put tx))
(.commit tx)
result))

(defn read-all-with-retry
[test n]
(scalar/check-transaction-connection! test)
(scalar/check-storage-connection! test)
(defn- read-record-with-retry
[test id]
(scalar/with-retry
(fn [test]
(scalar/prepare-transaction-service! test)
(scalar/prepare-storage-service! test))
test
(try
(let [tx (scalar/start-transaction test)
results (doall (map #(read-record tx @(:storage test) %)
(range n)))]
(.commit tx)
results)
(read-record test id)
(catch Exception e
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I think we can catch CrudConflictException if it's for the lazy recovery. What do you think?

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@brfrn169 Another exception could be thrown from the commit, couldn't it?

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@brfrn169 brfrn169 Nov 5, 2024 •
edited
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@yito88 Sorry, it seems I had the wrong idea. Please ignore the comment.

So currently, we retry all the record reads together, but after this PR, we will retry each record read individually. Is my understanding correct?

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@brfrn169 No problem. "read-record" tries to update, so it's a bit misleading.

we retry all the record reads together, but after this PR, we will retry each record read individually. Is my understanding correct?

Exactly!

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Thanks!

;; The transaction conflicted
;; Read failure or the transaction conflicted
(warn (.getMessage e))
nil))))

(defn read-all-with-retry
[test n]
(scalar/check-transaction-connection! test)
(scalar/check-storage-connection! test)
(doall (map #(read-record-with-retry test %) (range n))))

(defrecord TransferClient [initialized? n initial-balance max-txs]
client/Client
(open! [_ _ _]
Expand Down
25 changes: 14 additions & 11 deletions scalardb/src/scalardb/transfer_append.clj
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Original file line number Diff line number Diff line change
Expand Up @@ -128,30 +128,33 @@
:start-fail))

(defn- scan-records
"Scan records with a transaction. If the scan fails, an exception is thrown."
[tx id]
(let [results (.scan tx (prepare-scan id))]
"Scan records and append a new record with a transaction"
[test id]
(let [tx (scalar/start-transaction test)
results (.scan tx (prepare-scan id))]
;; Put the same balance to check conflicts with in-flight transactions
(->> (prepare-put id
(-> results first calc-new-age)
(-> results first (calc-new-balance 0)))
(.put tx))
(.commit tx)
results))

(defn scan-all-records-with-retry
[test n]
(scalar/check-transaction-connection! test)
(defn- scan-records-with-retry
[test id]
(scalar/with-retry scalar/prepare-transaction-service! test
(try
(let [tx (scalar/start-transaction test)
results (doall (map #(scan-records tx %) (range n)))]
(.commit tx)
results)
(scan-records test id)
(catch Exception e
;; The transaction conflicted
;; Scan failure or the transaction conflicted
(warn (.getMessage e))
nil))))

(defn scan-all-records-with-retry
[test n]
(scalar/check-transaction-connection! test)
(doall (map #(scan-records-with-retry test %) (range n))))

(defrecord TransferClient [initialized? n initial-balance max-txs]
client/Client
(open! [_ _ _]
Expand Down
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