PostgreSQL Internals

In PostgreSQL, multipass hash joins serve as a join algorithm that efficiently processes join operations between large tables. Unlike traditional hash joins, which require loading the entire hash table into memory, multipass hash joins follow […]

PostgreSQL Clustering_Factor In PostgreSQL, the clustering factor is a statistic that shows how closely the physical order of rows matches the logical order defined by the clustering key.This metric becomes especially important for tables that […]

In PostgreSQL, index height refers to the number of levels or layers within an index structure. Each level represents a layer of index blocks that store pointers to the actual data in a table. Understanding […]

In PostgreSQL, reverse key indexes can be used to reduce leaf block contention and improve performance in scenarios where there is high contention on the last block of an index. This technique is particularly beneficial […]

In PostgreSQL, tuning block sizes can have a significant impact on performance, especially for workloads that involve large sequential scans or high I/O operations. By adjusting the block size, you can optimize data storage and […]

While default values in PostgreSQL can be convenient and provide initial values for columns, certain default values can have a detrimental impact on PostgreSQL performance. Here are some examples of potentially deadly default values and […]

Query transformation is a key process in the PostgreSQL Cost-Based Optimizer (CBO) that allows the optimizer to modify a user’s SQL query in order to generate a more efficient query plan. In this process, the […]

In PostgreSQL, you can use the Median Absolute Deviation (MAD) to identify outliers in a dataset. MAD is a robust statistic that measures the variability of a dataset, and it is less sensitive to outliers […]

In PostgreSQL, you can use the isnumeric function to identify strings that can be treated as numbers. The isnumeric function returns TRUE if all characters in the string are numeric, and FALSE otherwise. Here is […]