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What is Full Text Search vs LIKE

sql
prompt-engineering
best-practices
indexing
Nikita BarsukovbyNikita Barsukov·Sep 10, 2024
TLDR

Full Text Search (FTS) utilizes advanced indexing to swiftly navigate sizable text data, supporting intricate queries such as word proximity and relevance ranking. It's your go-to tool for comprehensive textual analysis.

On the other side, we have LIKE, which provides basic pattern matching without the support of indexing. This results in slower searches as the data volume grows—however, it's perfect for simple, precise character matching.

Full Text Search example:

/* Searching for organic coffee, but hoping to avoid any heated debate on whether it's better than regular */ SELECT * FROM products WHERE MATCH(description) AGAINST('+organic +coffee' IN BOOLEAN MODE);

LIKE example:

/* Because sometimes you just want your coffee without worrying about its life choices */ SELECT * FROM products WHERE description LIKE '%organic%coffee%';

In essence, use Full Text Search for thorough, efficient text analysis, and LIKE for straightforward, exact pattern matching.

Deep-dive: Full Text Search and SQL LIKE

FTS exploits individual word indexing, offering rapid and efficient data retrieval. Beyond regular word indexing, the intrinsic lexical and morphological examination helps FTS deliver improved search accuracy, recognizing word variants and synonyms.

Pattern Recognition: SQL LIKE

The SQL LIKE operator manages basic pattern matching without any indexing perks. It's efficient for small datasets and fixed pattern searches. But be careful with leading wildcard queries (e.g., %term), as they can lead to full scans and slow down the operation on larger tables or unindexed columns.

Precision & Efficiency: FTS vs LIKE

In terms of performance on indexed columns, FTS addresses both precision and efficiency. It's particularly powerful in handling large text data, balancing a recall trade-off with 100% precision. On the flip side, the LIKE operation is not as efficient when tasked with unindexed columns or leading wildcards.

Right Tool for the Right Job: When to Use Which?

  1. Broad Text Analysis: Suitable for large, unstructured text datasets.
  2. Advanced Search: If the task requires text search with spatial awareness.
  3. Semantic Analysis: Ideal for stemming, synonyms recognition, and linguistic analysis.

The Realm of SQL LIKE

  1. Simple Pattern Match: If you're fishing for a fixed pattern within a dataset.
  2. Small-Scale Surveys: Suitable for small tables where full scans wouldn't significantly impact performance.
  3. Precise Searches: If the requirement is just basic "find and retrieve" without language nuances.

Enhancing Performance

A key to maximizing FTS is correctly indexing the relevant text columns. Proper indexing sidesteps unnecessary table scans and makes FTS far more efficient than wildcard-based LIKE searches.

Optimizing SQL LIKE

When LIKE is unavoidable, try to create partial indexes on frequently searched columns. Avoid leading wildcards if possible and create patterns that make use of existing B-tree indexes, as the performance of LIKE is proportional to your cleverness with it!

More Points to Consider

Wildcard Searches

FTS handles leading wildcard searches efficiently with pre-compiled suffix trees. With LIKE, leading wildcard can drastically slow down your query, like waiting for your avocado toast at a vegan café!

System Design

Investing in FTS usually needs proper planning with the database architecture to manage text indexes. It might involve extra storage or considerations around write operations. Think of it as deciding whether to get a cat—it might seem straightforward, but have you considered the extra chores and cat-sitter costs?

Future-Proofing Is Key

As the dataset grows and user demands evolve, transitioning from a LIKE-based search to FTS might become necessary. Designing your system with scalability in mind can save a lot of development time down the line.