# Question about stage EG2 - Fetch Single message from Disk **URL:** https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373 **Category:** Challenges **Tags:** challenge:kafka **Created:** [October 7, 2025, 7:30pm UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373 "2025-10-07T19:30:56Z") **Posts on this page:** 8 **Page:** 1
### Author: ![rajneeshks](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/rajneeshks/32/424_2.png) [@rajneeshks](https://forum.codecrafters.io/u/rajneeshks) #### Post date: [October 7, 2025, 7:30pm UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373/1 "2025-10-07T19:30:57Z")
I keep getting this error - what is that I am doing wrong? [tester::#EG2] [client] Hexdump of received “Fetch” response: [tester::#EG2] [client] Idx | Hex | ASCII [tester::#EG2] [client] -----±------------------------------------------------±---------------- [tester::#EG2] [client] 0000 | 00 00 00 91 29 fa 4f 2a 00 00 00 00 00 00 00 00 | …).O\*… [tester::#EG2] [client] 0010 | 00 00 00 02 71 a5 9a 51 89 68 4f 8b 93 7e c5 2d | …q..Q.hO..~.- [tester::#EG2] [client] 0020 | 86 e0 e4 56 02 00 00 00 00 00 00 00 00 00 00 00 | …V… [tester::#EG2] [client] 0030 | 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 00 | … [tester::#EG2] [client] 0040 | 00 00 00 00 00 00 00 00 02 00 00 00 00 00 00 00 | … [tester::#EG2] [client] 0050 | 00 00 00 00 3d 00 00 00 00 02 56 5c 25 ed 00 00 | …=…V%… [tester::#EG2] [client] 0060 | 00 00 00 00 00 00 01 91 e0 5b 6d 8b 00 00 01 91 | …[m… [tester::#EG2] [client] 0070 | e0 5b 6d 8b 00 00 00 00 00 00 00 00 00 00 00 00 | .[m… [tester::#EG2] [client] 0080 | 00 00 00 00 00 01 16 00 00 00 01 0a 61 70 70 6c | …appl [tester::#EG2] [client] 0090 | 65 01 00 00 00 | e… [tester::#EG2] [client] [tester::#EG2] [Decoder] - FetchResponse [tester::#EG2] [Decoder] - Header [tester::#EG2] [Decoder] - CorrelationID (704270122) [tester::#EG2] [Decoder] - Body [tester::#EG2] [Decoder] - ThrottleTimeMS (0) [tester::#EG2] [Decoder] - ErrorCode (0) [tester::#EG2] [Decoder] - SessionID (0) [tester::#EG2] [Decoder] - Topics [tester::#EG2] [Decoder] - Length (2 (Array length(1) + 1)) [tester::#EG2] [Decoder] - Topics[0] [tester::#EG2] [Decoder] - UUID (71a59a51-8968-4f8b-937e-c52d86e0e456) [tester::#EG2] [Decoder] - Partitions [tester::#EG2] [Decoder] - Length (2 (Array length(1) + 1)) [tester::#EG2] [Decoder] - Partitions[0] [tester::#EG2] [Decoder] - Id (0) [tester::#EG2] [Decoder] - ErrorCode (0) [tester::#EG2] [Decoder] - HighWaterMark (0) [tester::#EG2] [Decoder] - LastStableOffset (0) [tester::#EG2] [Decoder] - LogStartOffset (0) [tester::#EG2] [Decoder] - AbortedTransactions [tester::#EG2] [Decoder] - Length (0 (Null array)) [tester::#EG2] [Decoder] - PreferredReadReplica (0) [tester::#EG2] [Decoder] - RecordBatches [tester::#EG2] [Decoder] - Size (2 (Record size(1) + 1)) [tester::#EG2] [Decoder] - RecordBatches[0] [tester::#EG2] [Decoder] - Offset (0) [tester::#EG2] [Decoder] - Length (61) [tester::#EG2] [Decoder] - PartitionLeaderEpoch (0) [tester::#EG2] [Decoder] - MagicByte (2) [tester::#EG2] [Decoder] - CRC (1448879597) [tester::#EG2] [Decoder] - Attributes (0) [tester::#EG2] [Decoder] - LastOffsetDelta (0) [tester::#EG2] [Decoder] - FirstTimeStamp (1726045973899) [tester::#EG2] [Decoder] - MaxTimeStamp (1726045973899) [tester::#EG2] [Decoder] - ProducerID (0) [tester::#EG2] [Decoder] - ProducerEpoch (0) [tester::#EG2] [Decoder] - BaseSequence (0) [tester::#EG2] [Decoder] - Records [tester::#EG2] [Decoder] - Length (1) [tester::#EG2] [Decoder] - Records[0] [tester::#EG2] [Decoder] - Record [tester::#EG2] [Decoder] - Length (11) [tester::#EG2] [Decoder] - Attributes (0) [tester::#EG2] [Decoder] - TimestampDelta (0) [tester::#EG2] [Decoder] - OffsetDelta (0) [tester::#EG2] [Decoder] - KeyLength (-1) [tester::#EG2] [Decoder] - ValueLength (5) [tester::#EG2] [Decoder] - Value ([97 112 112 108 101] → UTF-8: (apple)) [tester::#EG2] [Decoder] - HeadersLength (-1) [tester::#EG2] [Decoder] ❌ RecordBatches (decode error) [tester::#EG2] Received bytes: [tester::#EG2] Hex (bytes 137-144) | ASCII [tester::#EG2] ------------------------------------------------±----------------- [tester::#EG2] 70 70 6c 65 01 00 00 00 | pple… [tester::#EG2] ^ ^ [tester::#EG2] Expected recordbatches size to be 73, got 1 [tester::#EG2] Test failed [tester::#EG2] Terminating program [your\_program] received 0 bytes, closing this socket!! [tester::#EG2] Program terminated successfully ---
### Author: ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li) #### Post date: [October 8, 2025, 1:35am UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373/4 "2025-10-08T01:35:31Z")
Hey @rajneeshks, could you [upload your code to GitHub](https://docs.codecrafters.io/features/publish-to-github) and share the link? It will be much easier to debug if I can run it directly. ---
### Author: ![rajneeshks](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/rajneeshks/32/424_2.png) [@rajneeshks](https://forum.codecrafters.io/u/rajneeshks) #### Post date: [October 8, 2025, 3:48am UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373/6 "2025-10-08T03:48:24Z")
Hi @andy1li - uploaded to github: > **[GitHub - saingarhia/codecrafters-kafka-rust](https://github.com/saingarhia/codecrafters-kafka-rust/tree/main)** > > main Specific code block that manages the response: > ---
### Author: ![andy1li](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/andy1li/32/10_2.png) [@andy1li](https://forum.codecrafters.io/u/andy1li) #### Post date: [October 8, 2025, 3:16pm UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373/8 "2025-10-08T15:16:38Z")
@rajneeshks The issue is caused by the hardcoded RecordBatches size: > ![image](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/3X/4/d/4d7392cf52a21dccbb29098b9278a750ec8e9ee2.png) Please note that RecordBatches are of type `COMPACT_RECORDS`: ![image](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/2X/d/d0a079441fc5d9f5f19a38cf1a6505449f48b107.png) ![image](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/2X/b/ba45c67877efe4fcd0cf4004e9c2f9c2b4199c3e.png) Let me know if you’d like further clarification! ---
### Author: ![CodeWithDawood](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/codewithdawood/32/18278_2.png) [@CodeWithDawood](https://forum.codecrafters.io/u/CodeWithDawood) #### Post date: [October 9, 2025, 9:02am UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373/10 "2025-10-09T09:02:59Z")
quite helpfull ---
### Author: ![CodeWithDawood](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/codewithdawood/32/18278_2.png) [@CodeWithDawood](https://forum.codecrafters.io/u/CodeWithDawood) #### Post date: [October 9, 2025, 9:04am UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373/11 "2025-10-09T09:04:09Z")
yup > **** > > This text will be hidden ---
### Author: ![rajneeshks](https://yyz1.discourse-cdn.com/flex003/user_avatar/forum.codecrafters.io/rajneeshks/32/424_2.png) [@rajneeshks](https://forum.codecrafters.io/u/rajneeshks) #### Post date: [October 9, 2025, 7:10pm UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373/12 "2025-10-09T19:10:25Z")
that helped, thank you so much! ---
### Author: ![system](https://canada1.discourse-cdn.com/flex003/uploads/codecrafters/original/3X/7/0/700657133935c15703e22c7c8870394f6e6dc27d.svg) [@system](https://forum.codecrafters.io/u/system) #### Post date: [October 14, 2025, 7:11pm UTC](https://forum.codecrafters.io/t/question-about-stage-eg2-fetch-single-message-from-disk/15373/13 "2025-10-14T19:11:24Z")
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