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Showing entries 601–640 of 775 in this first collection.
Troubleshooting guide
Consent mode order: set the default before any tag, then update when the visitor chooses
A technical guide to the order in which consent defaults, Google tags and a banner must run, how to check it in Tag Assistant, and what it does not decide for you. Not legal advice.
Troubleshooting guide
Google Ads conversion shows Unverified or Inactive: tag, linker, auto-tagging or a lost click ID
What the conversion statuses mean, how the click ID travels from ad to conversion page, where a redirect or missing linker breaks it, and how to test one conversion.
Troubleshooting guide
Meta Purchase event with no value, or counted twice: parameters, deduplication and how to test
What a Meta Purchase event needs, when deduplication applies and when it does not, and how to check one test event with Pixel Helper and Test Events.
Troubleshooting guide
Your checkout shows up as a referral: how GA4 carries one visitor across two domains
Why a hand-off to a booking or checkout domain splits a visit in two, how the _gl parameter and the domain list fix it, and the four reasons it goes missing.
Troubleshooting guide
Counting form submissions: the Tag Manager trigger, a custom event, or enhanced measurement?
When each way of detecting a successful form submission works, what Check Validation and Wait for Tags change, and a three-case test per form.
Troubleshooting guide
Server-side tagging for GA4: what the server container does, what a custom domain adds, what it does not fix
How a server container receives and forwards events, why the first-party subdomain matters, how to preview it, and the cost and consent questions to settle first.
Troubleshooting guide
Link Search Console to GA4, and write a one-page measurement plan before you build anything
The permissions, steps, limits and delay for linking Search Console to a GA4 web stream, and a measurement plan template that ties every event to a business question and a test.
Platform
Google Analytics 4 measurement problems: prove collection first, then read the reports
Where GA4 data goes wrong between the site and the report, with the quick checks, the documented limits and the bounded repairs that fit each fault.
Platform
Google Tag Manager: containers, previews and versions for safe tracking changes
How Tag Manager separates a container into workspaces, versions and preview, how the data layer feeds it, and which tracking repairs depend on each part.
Platform
Meta Pixel conversion events: check one test event before you trust the counts
What the Meta Pixel needs for Purchase events, how to see a test event arrive, when deduplication applies and where the Conversions API is a different job.
Buyer collection
For an online shop owner: when GA4 orders do not match the shop, test one order before you rebuild anything
Decide which of three faults you have, a missing event, a doubled purchase or an incomplete funnel, and ask for the smallest tested repair.
Buyer collection
For an agency: when Google Ads, Meta and GA4 disagree, check the chain link by link
Find the first broken link between a paid click and a counted conversion, agree what each platform can be compared on, and ask for tests that each client can watch.
Collection
Tracking diagnosis order: from "is the event sent?" to "is the report current?"
An ordered process map for finding the first broken link in a GA4 and Tag Manager set-up, with the guide and bounded outcome for each step.
Collection
Paid traffic measurement order: link, click ID, consent, hand-off, conversion tag, channel
An ordered process map for tracing a paid click to a counted conversion, with the first thing to check at each link of the chain and the guide for it.
Inspectable example
Synthetic record for one slow query: plan, timings and a rows-identical check
An invented before and after record showing what acceptance evidence for a single-query fix contains, including the write-cost line that is often left out.
Inspectable example
Synthetic query-count record for one endpoint: 101 queries to 2, with a ceiling test that fails on the old code
An invented before and after for a list endpoint, run in a small invented Django project: the query counts, a ceiling test written with CaptureQueriesContext, and the response comparison.
Inspectable example
Synthetic backfill log: new writes covered, batches, a resume, two reconciliations and a rollback run
An invented rehearsal log for adding and filling one column while rows keep arriving, showing the numbers that prove every row is right and that the rollback restored the starting structure.
Inspectable example
Synthetic replay matrix for a queue job: duplicate, concurrent and worker-death cases with a claim state and a lease
An invented table of delivery attempts and the expected effect and record for each, with a claimed or completed state, a lease and the written policy for a claim left behind by a dead worker.
Inspectable example
Synthetic write-path table for one cached object: who changes it, and what each path does to Redis
An invented table of the code paths that change one cached product and the invalidation, expiry and test each needs, with the longest an old value can stay stated as a number.
Inspectable example
Synthetic reconciliation report for merging duplicate customers: every row and reference accounted for
An invented report showing duplicate groups, the survivor rule, references repointed per table, the archive and reverse run, and the checks that nothing was orphaned.
Buyer collection
For an engineering manager: turn a slow, flaky service into measured data-layer items
Replace theories with a baseline, pick the smallest set of bounded database jobs the baseline supports, and agree acceptance before anyone changes an index.
Buyer collection
For a founder with a small dev team: the smallest database job that stops the surprises
A guide to choosing between a one-off fix, a monthly look and a bounded project when nobody on the team owns the database, with a tested backup as the first condition.
Troubleshooting guide
A database query is slow: read its plan on a copy before you add an index
How to compare estimated and actual rows, why EXPLAIN ANALYZE runs the statement, and what a before and after measurement must show before a fix counts.
Troubleshooting guide
The index exists but the query still scans the table: check column order, expressions and statistics
Why a database ignores an index: leading columns, expressions that do not match, tiny test tables and stale statistics, and how to test safely without forcing plans in production.
Troubleshooting guide
Before you drop an "unused" index: what usage counters can and cannot tell you
Index usage counters reset, miss monthly jobs, cover only one server and say nothing about constraints. How to judge the evidence period and drop safely.
Troubleshooting guide
An endpoint gets slower as the list grows: count its queries, then choose how to load relations
How to recognise a query-per-row pattern in Django, Rails or SQLAlchemy, the loading options each offers, and how a query-count test keeps it fixed.
Troubleshooting guide
A background job ran twice: record the operation in the database, do not rely on a lock
Why at-least-once queues repeat work, what an idempotency record with a unique constraint, a claim state and a lease does that a lock cannot, and the case where a worker dies mid-job.
Troubleshooting guide
Jobs reappear or vanish: visibility timeouts, retry counts and dead-letter queues explained
How a queue decides a message is still being worked, when it hands it out again, where failed messages go, and the alarms that stop them sitting unseen.
Troubleshooting guide
A cron job stopped or does nothing: check its environment, mail, percent signs and overlap
Why a command that works by hand fails from cron, how the scheduler treats environment, output, percent signs and day fields, and how to stop runs overlapping.
Troubleshooting guide
Alert when a scheduled job does not run: heartbeat checks, grace time and their blind spots
How a heartbeat monitor inverts alerting, how to choose a schedule and grace time, what start and fail signals add, and what the check cannot see.
Troubleshooting guide
Cache still shows the old value after an update: order of steps, expiry and key names
The four ways a Redis cache keeps stale data: invalidating before the commit, a missed write path, an overwrite that drops the expiry, and mismatched keys; plus why not to delete by pattern.
Troubleshooting guide
Duplicate rows in a table: choose a survivor, repoint references, keep a way back, then add the constraint
How duplicates arise, why deleting extras can orphan or cascade away data, a safe merge order with an archive and a reverse script, and the unique index that stops them returning.
Troubleshooting guide
Duplicate key error after an import or restore: the sequence is behind the data
Why new inserts collide with existing ids after rows are loaded with explicit ids, how to read the sequence against the maximum id, and how to set it safely.
Troubleshooting guide
Two branches both added a migration: reconcile Django, Alembic or Rails history before you deploy
What each migration tool does when two branches add migrations, how to merge the history safely, and why you never edit a migration that has already run in production.
Troubleshooting guide
Adding a column to a big table: which steps rewrite it and which locks they take
What PostgreSQL and MySQL do for ADD COLUMN, defaults, NOT NULL, foreign keys and indexes on a large table, and how to order the steps so writes keep flowing.
Troubleshooting guide
Backfill a new column in batches: resume safely and write the rollback first
How to fill a column across millions of rows without one giant transaction, how to prove every row is correct, and how to make the way back reversible and rehearsed.
Troubleshooting guide
Deadlocks and lock timeouts: read the database's record, fix the lock order, then set timeouts
How PostgreSQL and MySQL InnoDB report a deadlock, how to draw the cycle, why retries are the last step, and which timeout settings stop one stuck transaction taking the app down.
Troubleshooting guide
Timed out waiting for a database connection: pool size, leaks and server limits are different problems
How to tell an undersized pool from leaked connections, from many processes multiplying the pool, from a pooler mode that breaks features, using SQLAlchemy, Django, PostgreSQL and PgBouncer documentation.
Platform
MySQL performance and locking: read the plan, the slow log and the lock waits before changing anything
For teams on MySQL 8.x: where to look for slow statements, how InnoDB handles schema changes and deadlocks, and which bounded jobs fit.
Platform
Redis as a cache: expiry, eviction and invalidation decide whether users see fresh data
For teams using Redis in front of a database: how expiry is cleared by overwrites, what the memory limit does, why persistence is optional for a cache, and which bounded job fits.