After following, you can keep track of his dynamic information in a timely manner
MySQL 8.0 introduces InvisibleIndexes, allowing temporary hiding of indexes without deleting. 1. Set invisible when creating: Use CREATEINDEX...INVISIBLE; 2. Modify the existing index to invisible: ALTERINDEX...INVISIBLE; 3. Restore visible: ALTERINDEX...VISIBLE. The invisible index is still maintained, but does not participate in the implementation plan generation. It is suitable for testing the effect of new indexes and avoiding the risk of direct online launch. Backup and copy will retain their status, and FORCEINDEX cannot bypass invisibility, and is suitable for performance tuning and indexing strategy adjustment without affecting online services.
Aug 06, 2025 pm 03:20 PM
TomigrateolderapplicationstoMySQL8.0successfully,firstcheckapplicationcompatibility,thencarefullymigrateandconvertdata,updateconfigurationandsecuritysettings,andmonitorperformancepost-migration.1.Checkapplicationcompatibilitybyupdatingdatabasedrivers
Aug 06, 2025 pm 03:07 PM
Usearray_spliceforin-placeinsertionasitmodifiestheoriginalarraydirectly,ismoreefficient,andhassimplersyntax;2.Usearray_mergewitharray_slicewhenpreservingtheoriginalarrayisrequired,asitcreatesanewarraywithoutmutationandsupportsfunctionalprogrammingsty
Aug 06, 2025 pm 03:06 PM
QuarkusisaKubernetes-nativeJavaframeworkthatoptimizescloud-nativedevelopmentbyenablingfaststartup,lowmemoryusage,andseamlesscontainerintegration.1.Itsupportslivecodingwithinstantreloadvia./mvnwquarkus:dev.2.Itusesaunifiedconfigurationmodelthroughappl
Aug 06, 2025 pm 03:01 PM
Thenullcoalescingoperator(??)inPHPsafelyaccessesarraykeyswithouttriggeringnotices.1.Itreturnsthevalueifthekeyexistsandisnotnull;otherwise,itreturnsadefault.2.Itsimplifiesfallbacklogiccomparedtoisset()andternarychecks.3.Itpreservesfalsyvalueslike0,''o
Aug 06, 2025 pm 02:48 PM
Treat$\_SERVERvaluesasuntrustediftheycanbeinfluencedbyuserinput,suchasHTTP\_HOST,REQUEST\_URI,HTTP\_USER\_AGENT,HTTP\_REFERER,andQUERY\_STRING,sincethesecanbemanipulatedbyclients.2.Alwaysescape$\_SERVERdatausinghtmlspecialchars($\_SERVER['value'],ENT
Aug 06, 2025 pm 02:45 PM
Destructuringallowsselectiveextractionofarrayelementsintovariables,improvingreadabilityandreducingcodeverbosity.2.Thefind()methodretrievesthefirstelementmatchingacondition,whilefindIndex()returnsitsindex,bothofferingsaferandmorereadablealternativesto
Aug 06, 2025 pm 02:38 PM
Back up the data and confirm that the system meets the minimum Ubuntu requirements, including running Windows 11 in UEFI mode; 2. Compress at least 50GB of unallocated space from the C disk through the disk management tool; 3. Use Rufus to write Ubuntu ISO to more than 8GB USB disk and set it to GPT and UEFI modes; 4. Turn off fast boot in Windows and temporarily disable SecureBoot; 5. Boot from UEFIUSB, select the "Install Ubuntu parallel with WindowsBootManager" option to complete partitioning and installation; 6. Reboot after installation, if Windows does not display Windows on the GRUB menu, enter Ubuntu to run sudoupdate-
Aug 06, 2025 pm 02:35 PM
The sorting logic in PHP is significantly simplified using the Spaceship Operator(). 1. The operator compares two values and returns -1, 0 or 1, respectively, indicating that the left operand is less than, equal to or greater than the right operand, thereby replacing the lengthy if-else structure; 2. Use $a$b directly in usort, uasort and uksort to achieve ascending sort; 3. Multi-field sorting can be achieved through [$a['field1'],$a['field2']][$b['field1'],$b['field2']]]; 4. Descending sorting only requires exchanging the operand order, such as $b['age']$a['age']; 5. The object attribute sorting is also applicable, such as $a->age$
Aug 06, 2025 pm 02:28 PM
SQL can effectively improve retail sales and inventory efficiency. 1. When analyzing sales trends, count sales and order counts according to time dimensions (such as monthly), identify peaks and troughs, and group them into products or stores to find hot-selling categories; 2. By calculating inventory turnover rate (sales cost/average inventory), identify unsold products (large inventory and no sales in the past three months); 3. Forecast demand based on historical sales volume, and obtain replenishment suggestions based on current inventory; 4. Compare the sales performance and inventory turnover of different stores, discover operational shortcomings and optimize them in a targeted manner. By mastering these methods, you can use SQL to quickly mine the value of retail data.
Aug 06, 2025 pm 02:23 PM
breakexitstheloopimmediatelyafterfindingatarget,idealforstoppingatthefirstmatch.2.continueskipsthecurrentiteration,usefulforfilteringitemsliketemporaryfiles.3.gotojumpstoalabeledstatement,acceptableinrarecaseslikecleanuporerrorhandlingbutshouldbeused
Aug 06, 2025 pm 02:14 PM
UsedirectkeyassignmentforO(1)updates.2.Checkkeyexistenceonlywhennecessarytoavoidoverhead.3.BatchupdatesusingspreadorObject.assignforefficiency.4.PreferMapoverplainobjectsforfrequentupdates.5.Avoidinefficientfull-arrayreprocessingwhendirectupdatessuff
Aug 06, 2025 pm 02:13 PM
The recover function must be called in defer to capture panic; 2. Use recovery in long-running programs such as goroutine or server to prevent the entire program from crashing; 3. Recover should not be abused, only used when it is handled, to avoid replacing normal error handling; 4. Best practices include recording panic information, using debug.Stack() to obtain stack traces and recovering at an appropriate level. Recover is only valid within defer and should be used for debugging with logs. Potential bugs cannot be ignored. In the end, the code should be designed by returning error rather than panic.
Aug 06, 2025 pm 02:08 PM
Stickysessions are needed because the default load balancing will cause session loss, especially when applying local storage sessions; 1. Use sticky module to implement based on cookies, automatically allocate and maintain routing; 2. Use sticky-route to support complex routing logic; 3. Use ip_hash to be simple but easily cause uneven load; it is recommended to use stickycookies temporarily to migrate, and the session should be externally assigned to Redis for a long time to improve architectural flexibility.
Aug 06, 2025 pm 02:04 PM
TouseregexinSublimeText'sFindandReplace,firstenableregexmodebyopeningtheFindpanelwithCtrl F(Windows/Linux)orCmd F(macOS),clickingthe.button,orusingAlt R(Windows/Linux)orOption R(macOS).Next,applybasicpatternslike\d fordigits,\b\w{5}\bfor5-letterwords
Aug 06, 2025 pm 01:58 PM
lsmod lists loaded modules, insmod directly inserts the module but does not handle dependencies, modprobe intelligently loads and solves dependencies; 1. Use lsmod to view the currently loaded module and its dependencies; 2. Use insmod./mymodule.ko to manually load a single module, and make sure that the dependencies are met; 3. Use modprobeusb_storage to automatically load the module with dependencies, or modprobe-rusb_storage to unload the module; it is recommended to use modprobe in daily life, use insmod to debug if necessary, monitor the status through lsmod, update the dependency database with depmod-a, and view module information in modinfo, so as to
Aug 06, 2025 pm 01:48 PM
Select the appropriate cache type, such as Caffeine is preferred for in-heap cache, and Redis or Hazelcast is used in distributed environments; 2. Use Caffeine to achieve high-performance local cache, configure size and expiration policies, and automatically load data through get methods; 3. Use @EnableCaching and @Cacheable annotations in SpringBoot to implement declarative cache to simplify management; 4. Timely cache failure during write operations, set reasonable TTL and use refreshAfterWrite to avoid cache breakdown; 5. Monitor cache performance by recording indicators such as hit rate and eviction rate, and integrate monitoring with tools such as Micrometer.
Aug 06, 2025 pm 01:45 PM
ThetransientkeywordinJavaexcludesfieldsfromserialization;1)itpreventssensitivedatalikepasswordsfrombeingsaved;2)ithandlesnon-serializableobjectssuchasThreadorSocket;3)itimprovesperformancebyskippingunnecessarydata;4)duringdeserialization,transientfie
Aug 06, 2025 pm 01:39 PM
When binding form data to the model in web development, it is recommended to use the framework's own mechanism first, followed by manual binding and attention to field matching, structure nesting and data verification. Specific practices include: 1. Use built-in functions of the framework, such as ModelBinder of ASP.NETCore, @RequestBody of SpringBoot, ModelForm of Django, etc., to automatically complete type conversion and security verification; 2. Get request data in sequence, create model instances, and assign fields one by one (such as assigning req.body to User object in Express); 3. Ensure that the form field name is consistent with the model attributes, handle nested structures, and it is recommended to use DTO to isolate inputs.
Aug 06, 2025 pm 01:19 PM
Linux file permissions are used to control users' access to files, ensure system security and legal use of resources. 1. File permissions are divided into read (r), write (w), and execute (x), corresponding to the values 4, 2, and 1, respectively; 2. Permission objects are divided into owner (u), group (g), and other (o); 3. Use ls-l to view permissions, and chmod modify permissions through symbolic mode (such as u x) or digital mode (such as 755); 4. Chown and chgrp are used to change the owner and group of files, and usually require root permissions; 5. Special permissions include SUID (execute as owner when the file is running), SGID (execute as group or file inheritance group in the directory) and sticky bits (StickyBit, only text
Aug 06, 2025 pm 12:56 PM
To optimize nested foreach loops, redundant iterations should be avoided first, and the time complexity can be reduced from O(n×m) to O(n m); second, if the structure is not truly hierarchical, the data should be flattened using methods such as SelectMany; third, jump out in advance or skip unnecessary processing through conditional judgment; fourth, select appropriate data structures such as dictionary or hash sets to improve search efficiency; fifth, parallelization can be used with caution when operations are independent and time-consuming; sixth, extract complex logic into independent methods or queries to improve readability and maintainability. The core of optimization is to reduce complexity, organize data reasonably, and always evaluate the necessity of nesting, ultimately achieving efficient, clear and extensible code.
Aug 06, 2025 pm 12:53 PM
Keepthesystemupdatedandremoveunnecessarysoftwaretominimizevulnerabilities;2.Enforcestrongpasswordpolicies,disablerootSSHlogin,usesudo,andmanageuseraccesscarefully;3.HardenSSHbychangingthedefaultport,disablingpasswordauthentication,usingkey-basedlogin
Aug 06, 2025 pm 12:43 PM
Thread-SafeSingleton uses the Initialization-on-DemandHolder mode to ensure thread safety and avoid explicit synchronization; 2. Producer-Consumer mode uses BlockingQueue to decouple producers and consumers, and uses its blocking characteristics to achieve efficient and thread-safe task delivery, suitable for event processing and logging systems; 3. WorkerThreadPool manages thread resources through ThreadPoolExecutor, sets core and maximum number of threads, bounded queues and reasonable rejection strategies, improves task scheduling efficiency and prevents resource exhaustion, widely
Aug 06, 2025 pm 12:29 PM
First of all, we must clarify the answer: the core of JVM tuning is to reasonably configure memory, choose appropriate GC policies and continuously monitor. 1. Understand the JVM memory structure and focus on optimizing the ratio of the new generation to the elderly in the heap; 2. Select the GC type according to the application scenario, and recommend G1 or ZGC to balance the delay and throughput; 3. Finely set the -Xms, -Xmx, -Xmn and Metaspace parameters to avoid dynamic capacity expansion overhead; 4. Turn on the GC log and use GCViewer or GCEasy analysis to adjust the strategy based on the data; 5. Avoid code traps such as large object creation, memory leaks, and frequent string splicing; 6. Continuous monitoring of tools such as jstat, jmap, jstack and Prometheus to build
Aug 06, 2025 pm 12:13 PM
When deleting array elements, the array should not be modified directly in the foreach loop, because this will cause the elements to be skipped or the behavior is unpredictable. The correct way is: 1. Use reverse for loop to traverse and delete to avoid index misalignment; 2. Collect the keys or indexes to be deleted first, and then remove them uniformly after the loop ends; 3. Use filter and other methods to create new arrays instead of modifying the original array. These methods ensure safe and reliable processing of arrays and avoid bugs caused by iterator pointer confusion. The final conclusion is that you should never directly modify the array being traversed in foreach.
Aug 06, 2025 pm 12:09 PM
Schema is designed according to the query pattern. Data that is checked at high frequency is embedded, and multiple are used for independent updates are updated; 2. Embedding is suitable for a small pair, and references are suitable for big data or frequent updates; 3. Control the document size to avoid expansion and move, and build a collection of growing data separately; 4. Accurate index design, analyze slow queries, and make good use of composite and overlay indexes; 5. Unify the style and type of field naming to avoid chaos in later maintenance. These practices help you leverage MongoDB performance advantages and make the structure efficient and easy to maintain.
Aug 06, 2025 am 11:59 AM
Becoming a Yii developer in 2024 requires mastering the following skills: 1. Proficient in the Yii framework and its core components; 2. Proficient in modern PHP and Web technologies; 3. Have front-end skills, familiar with JavaScript, etc.; 4. Be able to develop and use RESTfulAPI; 5. Pay attention to security and best practices; 6. Understand DevOps and deployment tools; 7. Have good soft skills and problem-solving capabilities; 8. Continue to pay attention to the latest trends in the Yii ecosystem.
Aug 06, 2025 am 11:58 AM
ConfigureTypeScriptwithstrictsettingsandmodernEStargetsfortypesafetyandperformance.2.OptimizeExpressmiddlewarebylimitingpayloadsize,applyingmiddlewareselectively,andavoidingunnecessaryfunctions.3.Useacleanarchitecture(routes→controllers→services→repo
Aug 06, 2025 am 11:57 AM
After the root directive appends the URL path to the specified directory, if location/static/ is equipped with root/var/www/html, the corresponding file path of /static/css/app.css is requested as /var/www/html/static/css/app.css; 2. The alias directive completely replaces the location matching path with the specified directory, if location/static/ is equipped with alias/var/www/assets/, the corresponding file path of the same request is /var/www/assets/css/app.css; 3. A common error is to mistake root as alias
Aug 06, 2025 am 11:51 AM
InnoDB's architecture design includes logical storage structure, memory structure, transaction and logging system, and optimization features. 1. The logical storage structure is divided into tablespace, segments, zones and pages, supporting transactions and efficient data management. 2. The buffer pool in the memory structure caches data, reduces disk I/O, and manages page exchange in and out through the LRU algorithm. 3. The transaction mechanism depends on RedoLog and UndoLog, which is used for crash recovery, and UndoLog is used for rollback and MVCC. 4. Insert buffer optimization non-unique secondary index insertion, adaptive hash index accelerates equivalent query, and is enabled by default to improve performance.
Aug 06, 2025 am 11:42 AM
