To check which storage engine a table uses, query the information_schema database: SELECT ENGINE FROM information_schema.TABLES WHERE TABLE_SCHEMA = ‘database_name’ AND TABLE_NAME = ‘table_name’; Replace database_name and table_name with your actual values. You can also use the SHOW TABLE STATUS command for a quicker view: SHOW TABLE STATUS FROM database_name WHERE Name = ‘table_name’\G The…
You’re seeing fatal errors because PHP has hit its default resource constraints: PHP Fatal error: Maximum execution time of 30 seconds exceeded PHP Fatal error: Allowed memory size of 268435456 bytes exhausted These limits exist to prevent runaway scripts from consuming server resources. Here’s how to increase them. Via php.ini (Global Configuration) The most reliable…
Database corruption happens. Whether it’s from unexpected shutdown, filesystem errors, or hardware issues, knowing how to recover from backups is essential sysadmin knowledge. When to Use Backups vs. Native Repair Tools Before jumping to restore from backup, consider your options: Native repair tools (REPAIR TABLE, CHECK TABLE) are faster and preserve recent data Backup restoration…
Choosing the right number of mappers and reducers directly impacts Hadoop job performance. This isn’t a set-and-forget configuration—it depends on your cluster characteristics, data size, and task complexity. Mapper Configuration The number of mappers is primarily determined by the number of HDFS blocks in your input files. Each block typically generates one map task by…
Chrome on iOS implements aggressive caching to improve browsing performance, but this can prevent you from seeing the latest versions of pages, stylesheets, and scripts. Unlike Safari’s convenient long-press refresh button, Chrome’s cache management is less intuitive. The Nuclear Option: Clear All Cache The most straightforward approach is clearing all cached data: Open Chrome Tap…
If you’re seeing elevated TCP segment retransmission counts on Xen VMs, this typically signals network congestion, packet loss, or CPU contention. Here’s how to identify the root cause and fix it. Check Your Current Retransmission Rate Start by gathering baseline metrics: ss -s Look for the retransmit counters: TCP: established 45 tw 3 alloc 48…
Facebook operates two distinct caching systems, each designed for different access patterns and consistency requirements. Memcache serves as a lookaside cache where the intelligence resides primarily on the client side. This architecture means applications are responsible for cache invalidation, consistency checks, and determining what data to cache. Memcache is stateless and horizontally scalable, making it…
You’ll sometimes need to exclude specific repositories from package operations—typically when multiple repos provide the same package, mirror connectivity is unreliable, or you want to force installation from a trusted source. The –disablerepo flag lets you skip repos on a per-command basis. Basic syntax dnf –disablerepo=repoid1 –disablerepo=repoid2 install package-name Add –disablerepo once for each repo…
Scala runs on the JVM and combines object-oriented and functional programming. Here’s how to install Scala on Fedora Linux using several methods. Method 1: Install via Coursier (Recommended) Coursier is the official Scala installer and handles JDK dependencies automatically: # Install Coursier curl -fL https://github.com/coursier/coursier/releases/latest/download/cs-x86_64-pc-linux.gz | gzip -d > cs && chmod +x cs &&…
If you need to clean up spam content across your MyBB forum quickly, the Goodbye Spammer plugin automates the process of banning a user and removing all their content in one operation. Installation Download the Goodbye Spammer plugin from the MyBB Mods site, then: Upload ./inc/plugins/goodbyespammer.php to ./inc/plugins/ Upload ./inc/languages/english/goodbyespammer.lang.php to ./inc/languages/english/ Navigate to ACP…
Question2Answer’s RSS feed configuration includes a toggle for “Include full text in feeds” but offers no built-in option to display excerpts instead of full content. If you need excerpt functionality, you’ll need to modify the feed generation code. This approach works with Question2Answer 1.5.4+. The method involves creating a custom feed handler that truncates content…
Converting Word documents to PDF is a fundamental task in most workflows. Modern versions of Office have native PDF export built in, but understanding your options and potential gotchas will save you time. Native PDF Export (Modern Office) If you’re using Office 2010 or later, PDF export is built into the application—no add-ons required. Open…
You can run OCaml scripts directly from the command line with a shebang, similar to bash or Python. This requires making the file executable and using the proper interpreter directive. Basic Script Setup Create a file with a .ml extension and add a shebang at the top: #!/usr/bin/env ocaml print_endline “Hello world!”;; Then make it…
Y-axis labels in Gnuplot can end up positioned awkwardly depending on your terminal, font, and tick label width. The most straightforward solution is using the offset option in the set ylabel command. Basic Offset Syntax The offset takes three parameters: horizontal, vertical, and depth (for 3D plots): set ylabel “Y Label” offset <x_offset>,<y_offset>,<z_offset> Positive values…
Font sizes in Gnuplot plots often appear too small when scaling images down for papers or presentations. You can control font sizes at multiple levels: globally for the terminal, for axis labels and tick marks, for legends, and for individual text elements. Global Terminal Font Size Set a default font and size for your entire…
The common claim that cin is significantly slower than scanf in C++ is partially true, but only when comparing default configurations. The reality is more nuanced. Why cin Can Be Slower by Default By default, C++ streams maintain synchronization with C stdio streams (stdin, stdout, stderr). This synchronization requires additional overhead because the library must…
OCaml’s int type size depends on your platform’s architecture. On 64-bit systems, int is 63 bits; on 32-bit systems, it’s 31 bits. This catches many people off guard when they test bitwise operations. Here’s why: OCaml uses one bit as a tag to distinguish integers from pointers at runtime (the least significant bit). So on…
Consistency models define the guarantees that a distributed system makes about the order and visibility of data modifications across nodes. Understanding these models is essential when designing systems, choosing databases, or debugging data anomalies in production. Strong Consistency Models Strict Consistency is the ideal but rarely achievable model. It guarantees that reads always reflect the…
GNOME can automatically restore your session—reopening all applications and windows that were running when you last logged out. This differs from autostart scripts, which launch specific programs on every login regardless of what was running before. Automatic Session Restoration To enable automatic session restoration in GNOME: Open Settings → General (or search “Session” in Activities)…
If you’re running Question2Answer and want to replace the default search with Google Custom Search without modifying your theme, a plugin is the cleanest approach. Setup Requirements Before implementing Google Custom Search, you’ll need: A Google account Google Custom Search Engine (CSE) created at cse.google.com Your CSE ID (cx parameter) Question2Answer 1.8+ installed and functioning…