Questions tagged [serialization]

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PostgreSQL Race condition and Serializable

Hello I try to debug a tricky race condition in my app (golang, pq, sqlx, postgresql Debian 10.6-1.pgdg90+1). I have a table CREATE TABLE j ( id BIGSERIAL PRIMARY KEY NOT NULL, ...
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What is the meaning of Order preserving Conflict Serializable schedules?

I was going through the concept of order preservation in Conflict Serializable class and I came across Order preserving conflict serializable (OCSR in short). The following is the definition of OCSR ...
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37 views

View serializable schedule

Any view serializable schedule that is not conflict serializable must contain a blind write. (Source: Wikipedia) Why is this statement true? I referred some links like this but am still not able to ...
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1answer
265 views

Forced serialization on inline table valued function

Apologies if this is a stupid question. We are attempting to convert our multi-statement table valued functions (MSTVFs) to inline table valued functions (ITVFs), to avoid the forced serialization of ...
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2answers
574 views

Are MySQL InnoDB transactions serializable?

I am confused whether or not MySQL transactions are serializable and whether or not read-anomalies are guarded against? For example, what if I SELECT a value from a row, then UPDATE that row by ...
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1answer
42 views

Serializability schedules: can someone help me understand it?

I am struggling with the Databases courses I have, so I am trying to find answer to my question. This has been asked: Add the appropriate locks to enforce serializability on the following ...
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Do start and end points change conflict serialisability?

If we have two transactions, and the following schedule: S1 R1(X) S2 R2(X) R2(Y) E1 W2(X) W2(Y) E2 where Si and Ei indicate the start and end of the ith transaction respectively. Does this change ...
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1answer
464 views

Storing data in multiple rows vs serialized data

I am currently designing a database table where I store list of courses chosen by students for a session. My current design has to do with storing each course in a row and a student can have up to 30 ...
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1answer
380 views

Postgres: turn off formating for xml export?

I want to export some table to xml file: \o output.xml SELECT table_to_xml('modified_records', TRUE, TRUE, ''); However, I'm struggling with psql formatting. The best I managed to get is: \t on \x ...
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3answers
5k views

What is meant by a blind write in a schedule?

I know that every conflict-serialisable schedule is view-serialisable but the converse is not true. I read in a webpage that when a schedule is view-serialisable but not conflict-serialisable then ...
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1answer
400 views

PostgreSQL visibility of records changes from other transaction inside the current one

I have a table "tst" which has a "status" column using which we process records in that table. Once the records are processed we set the status to 'Y'; #\d tst Table "core.tst" ...
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1answer
603 views

Challenges with Key with Gaps?

I had a mistake with a trigger which resulted in errors in PostgreSQL 9.4.3 on x86_64-unknown-linux-gnu, compiled by gcc (Debian 4.9.2-10) 4.9.2, 64-bit. Each time during the error, the primary key ...
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1answer
13k views

SELECT in trigger function in two tables

My table and trigger in PostgreSQL 9.4.3 on x86_64-unknown-linux-gnu, compiled by gcc (Debian 4.9.2-10) 4.9.2, 64-bit: CREATE TABLE measurements ( measurement_id SERIAL PRIMARY KEY NOT NULL, ...
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1answer
1k views

debugging PostgreSQL serialization failures

I am trying to migrate our PostgreSQL 9.4 database from transaction level READ COMMITTED to either REPEATABLE READ or SERIALIZABLE. In either case, I'm exposed to a new set of errors with the format: ...
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1answer
285 views

Does READ COMMITTED always start over after serialization failures while SERIALIZABLE simply fails?

On the PostgreSQL Concurrency With MVCC page, it says: know what you’re thinking though: what about a two transactions updating the same row at the same time? This is where transaction isolation ...
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0answers
134 views

Turn off serialization failure logging

Is it possible to turn off serialization failure logging? If so, how? For example, my log is filled with this example: ERROR: could not serialize access due to read/write dependencies among ...
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1answer
843 views

How to configure read transactions to never cause other write serialization transactions to fail

I am protecting critical transactions with application mutexes and SERIALIZABLE. I presume that this makes these operations as acid as possible, but now I'm concerned that reads might cause failures ...
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3answers
4k views

psql: id SERIAL PRIMARY KEY not starting with 1?

This is something I don't understand, can somebody explain? I create a table CREATE TABLE cali (id SERIAL PRIMARY KEY, ALK_from char, ALK_to char, AND_from char, AND_to char); Then ...
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5answers
21k views

Locking issue with concurrent DELETE / INSERT in PostgreSQL

This is pretty simple, but I'm baffled by what PG does (v9.0). We start with a simple table: CREATE TABLE test (id INT PRIMARY KEY); and a few rows: INSERT INTO TEST VALUES (1); INSERT INTO TEST ...
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2answers
3k views

How do I implement insert-if-not-found for transactions at serializable isolation level?

I'm having a hard time figuring out how to exactly implement a 'insert if not found' function. Consider the following. We have a table called artist with 2 columns, (name, id) where name is the ...
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1answer
2k views

Send data from SQL to a serial port or IP address

I've been asked to integrate SQL transaction data with a video monitoring system in real-time. The video system's application is only capable of receiving data by listening on a serial port or a ...
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1answer
2k views

Data type for protobuf objects in mysql

I would like to store some protobuf objects in a MySQL database. The objects are created in a Java application. The object is accompanied with a textual type identifier and a timestamp. +------------+...