Andrei Pechkurov (@puzpuzpuz)

Multithreaded Execution Model for Queries With ORDER BY and LIMIT Clauses

This small post continues the previous post dedicated to multithreaded query execution in databases with column-oriented storage format. This time we'll consider queries like the following: SELECT SearchPhrase FROM hits WHERE SearchPhrase IS NOT NULL...

Jun 9, 2024 · 2 min readpuzpuzpuz.dev

An mmap-based hash table optimization

mmap is a controversial topic among the database community. The common belief is that it's no good for a database, but in my experience, it does a decent job for an analytical database, when you want to scan columns stored in a column-oriented format...

Jun 1, 2024 · 2 min readpuzpuzpuz.dev

Seqlock-Based Atomic Memory Snapshots

Last time we discussed k-word CAS algorithm and came to the conclusion that seqlock-based atomic snapshots may be used as an alternative in situations when your writes are infrequent and single-writer limitation is acceptable, but you want the reader...

1Aug 6, 2023 · 5 min readpuzpuzpuz.dev

A Few Thoughts on K-Word CAS

A few months ago I went through Efficient Multi-word Compare and Swap paper, so here are a few thoughts on the algorithm. Long story short, I have mixed feelings about this k-word CAS algorithm. It focuses on nice properties of the CAS operation, suc...

Jul 6, 2023 · 2 min readpuzpuzpuz.dev

The Secret Life of fsync

Several times I've heard opinions that many mass-market SSDs and HDDs don't provide sufficient durability guarantees and Linux can do nothing with that. Namely, after an fsync() call recently modified data can still sit in the drive's volatile write ...

Mar 31, 2023 · 4 min readpuzpuzpuz.dev

Andrei Pechkurov

About

Available for

Andrei Pechkurov's blogs

Multithreaded Execution Model for Queries With ORDER BY and LIMIT Clauses

An mmap-based hash table optimization

Seqlock-Based Atomic Memory Snapshots

A Few Thoughts on K-Word CAS

The Secret Life of fsync

Andrei Pechkurov

About

Available for

Andrei Pechkurov's blogs

Multithreaded Execution Model for Queries With ORDER BY and LIMIT Clauses

An mmap-based hash table optimization

Seqlock-Based Atomic Memory Snapshots

A Few Thoughts on K-Word CAS

The Secret Life of fsync

Andrei Pechkurov

About

Available for

Andrei Pechkurov's blogs

Multithreaded Execution Model for Queries With ORDER BY and LIMIT Clauses

An mmap-based hash table optimization

Seqlock-Based Atomic Memory Snapshots

A Few Thoughts on K-Word CAS

The Secret Life of fsync

Search Hashnode

Andrei Pechkurov

About

Available for

Andrei Pechkurov's blogs

Multithreaded Execution Model for Queries With ORDER BY and LIMIT Clauses

An mmap-based hash table optimization

Seqlock-Based Atomic Memory Snapshots

A Few Thoughts on K-Word CAS

The Secret Life of fsync