Mechanisms for accessing database records locally

Patent metadata

Field	Value
Publication number	US-12468690-B1
Application number	US-202418977106-A
Country	US
Kind code	B1
Filing date	Dec 11, 2024
Priority date	Dec 11, 2024
Publication date	Nov 11, 2025
Grant date	Nov 11, 2025

Abstract

Techniques are disclosed that pertain to a database system having a log owner and log tailers. The log owner maintains a transaction log and the log tailers replay the transaction log. A log tailer may receive a set of requests to perform a database transaction that involves a write operation to write a record and a subsequent read operation to read that record. As a part of performing the transaction, the log tailer may issue a request to the log owner to log the write operation in the transaction log and the log tailer may insert the record into a local memory structure of the log tailer. After receiving a response from the log owner that the write operation has been logged, the log tailer may permit the subsequent read operation to access the record from the local memory structure without requesting the record from the log owner.

First claim

What is claimed is:

1 . A method, comprising:
receiving, by a log tailer of a plurality of log tailers of a database system, a set of requests to perform a database transaction that involves a write operation to write a record and a subsequent read operation to read the record, wherein the database system includes 1) a log owner that maintains a transaction log and 2) the plurality of log tailers that replay the transaction log, and wherein the transaction log describes operations performed in the database system; and performing, by the log tailer, the database transaction, wherein the performing includes:
issuing a request to the log owner to log the write operation in the transaction log;
inserting the record into a local memory structure of the log tailer; and
subsequent to receiving a response from the log owner that the write operation has been logged, permitting the subsequent read operation of the database transaction to access the record from the local memory structure of the log tailer without requesting the record from the log owner.

2 . The method of claim 1 , further comprising:
assigning, by the log tailer, a unique transaction identifier to the database transaction; and providing, by the log tailer, the unique transaction identifier to the log owner to include in the transaction log to associate the record with the unique transaction identifier, wherein the unique transaction identifier is usable by the log tailer to prevent a duplicate of the record from being inserted into the local memory structure during a replay of the transaction log.

3 . The method of claim 2 , further comprising:
assigning, by the log tailer, a reusable transaction identifier to the database transaction that has a different lifecycle than the unique transaction identifier, wherein the reusable transaction identifier associates a backend process with the database transaction, and wherein the reusable transaction identifier is released after the database transaction is committed from the perspective of the backend process.

4 . The method of claim 2 , wherein the log owner is operable to include the unique transaction identifier in a log record associated with an initial write operation of the database transaction but exclude the unique transaction identifier from log records associated with subsequent write operations of the database transaction.

5 . The method of claim 2 , further comprising:
subsequent to the assigning, the log tailer adding the unique transaction identifier to an active list; and before the inserting of the record into the local memory structure, the log tailer determining whether the unique transaction identifier is present on the active list, wherein the inserting is performed based on determining that the unique transaction identifier is still present on the active list.

6 . The method of claim 2 , wherein the record is inserted with a memory identifier into the local memory structure, wherein the memory identifier has a smaller memory size than the unique transaction identifier, and wherein the method further comprises:
maintaining, by the log tailer, a mapping between the memory identifier and the unique transaction identifier; and determining, by the log tailer during the replay of the database transaction, that the record is present in the local memory structure based on the mapping.

7 . The method of claim 2 , wherein at least a portion of the unique transaction identifier identifies the log tailer from the plurality of log tailers.

8 . The method of claim 1 , wherein the inserting of the record into the local memory structure is performed subsequent to the receiving of the response from the log owner.

9 . The method of claim 1 , further comprising:
determining, by the log tailer, whether a replay of the database transaction has been initiated within a threshold amount of time after the database transaction has been committed; and in response to determining that the replay of the database transaction has not been initiated within the threshold amount of time, the log tailer evicting the record from the local memory structure.

10 . The method of claim 1 , further comprising:
determining, by the log tailer, whether the local memory structure satisfies a fullness threshold; and in response to determining that the local memory structure satisfies the fullness threshold, the log tailer preventing uncommitted database transactions from inserting records into the local memory structure.

11 . A non-transitory computer-readable medium having program instructions stored thereon that are capable of causing a computer system to implement a log tailer that performs operations comprising:
receiving a set of requests to perform a database transaction that involves a write operation to write a record and a subsequent read operation to read the record; performing the database transaction, wherein the performing includes:
issuing a request to a log owner to log the write operation in a transaction log that describes a set of performed operations; and
subsequent to receiving a response from the log owner that the write operation has been logged:
inserting the record into a local memory structure of the computer system; and
permitting the subsequent read operation of the database transaction to access the record from the local memory structure without requesting the record from the log owner; and

replaying the database transaction via the transaction log, wherein the replaying includes preventing a duplicate of the record from being inserted into the local memory structure.

12 . The non-transitory computer-readable medium of claim 11 , wherein the operations further comprise:
assigning a unique transaction identifier to the database transaction; and providing the unique transaction identifier to the log owner to include in the transaction log to associate the record with the unique transaction identifier, wherein the preventing of the duplicate from being inserted into the local memory structure is performed based on detecting the unique transaction identifier during the replaying of the transaction log.

13 . The non-transitory computer-readable medium of claim 12 , wherein the operations further comprise:
adding the unique transaction identifier to an active list, wherein the inserting is performed in response to determining that the unique transaction identifier is still present on the active list; and in response to detecting that the database transaction has been aborted, removing the unique transaction identifier from the active list to prevent subsequent record insertions for the database transaction into the local memory structure.

14 . The non-transitory computer-readable medium of claim 12 , wherein the operations further comprise:
generating a transaction sequence number, wherein the unique transaction identifier identifies 1) the log tailer from a plurality of log tailers and 2) the transaction sequence number.

15 . The non-transitory computer-readable medium of claim 11 , wherein the operations further comprise:
determining whether the local memory structure satisfies a fullness threshold; and based on determining that the local memory structure satisfies the fullness threshold and the database transaction has not been replayed via the transaction log, evicting the record from the local memory structure.

16 . A system, comprising:
at least one processor; and memory having program instructions stored thereon that are executable by the at least one processor to cause the system to implement a secondary database node

Assignees

• Salesforce Inc

Inventors

• Busjaeger Benjamin
• Dantkale Suhas
• Abebe Michael

Classifications

• G06F16/2358

  Change logging, detection, and notification (replication G06F16/27) · CPC title

• G06F16/2379 Primary

  Updates performed during online database operations; commit processing · CPC title