Questions tagged [serialization]
The serialization tag has no usage guidance.
22
questions
0
votes
0answers
39 views
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,
...
2
votes
0answers
65 views
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 ...
1
vote
0answers
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 ...
3
votes
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 ...
1
vote
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 ...
1
vote
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
...
1
vote
0answers
15 views
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 ...
0
votes
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 ...
0
votes
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 ...
2
votes
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 ...
1
vote
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"
...
4
votes
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 ...
4
votes
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,
...
6
votes
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:
...
2
votes
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 ...
1
vote
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 ...
1
vote
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 ...
1
vote
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 ...
35
votes
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 ...
5
votes
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 ...
3
votes
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 ...
2
votes
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.
+------------+...
