Protocol Coverage

An HTTP Cookie Manager gives every JMeter thread its own cookie store: it saves the cookies a response sets and replays the matching ones on later requests to that site, so each thread holds a separate session.

A JDBC Connection Configuration element whose Variable Name for created pool matches the sampler's pool field, plus the vendor's driver jar in JMeter's lib directory. A name mismatch fails the sample with "No pool found named".

Through a JNDI lookup. Either tick Use jndi.properties file, or fill in Initial Context Factory and Provider URL on the sampler itself; Connection Factory and Destination name what is looked up either way. The provider's own client JAR must already sit in JMeter's lib directory.

A Thread Group with a Recording Controller under it. The recorder's Target Controller defaults to Use Recording Controller, and pressing Start with no Recording Controller anywhere in the tree raises an error instead of opening the proxy.

Follow Redirects makes JMeter chase the Location itself and record every hop as a sub-sample. Redirect Automatically hands the chase to the HTTP client, so the hops never become samples. The two checkboxes are mutually exclusive.

Zero turns off sharing. Each JMeter thread lazily builds its own DBCP pool holding a single connection, so no thread ever waits on another. Any positive number builds one pool of that size shared by every thread.

Both fields hold regular expressions matched against the whole host:port/path?query string. With any Include pattern present the URL must match one, and matching any Exclude pattern drops it. Filtering decides what is recorded, not what the browser receives.

A recording is a draft. JMeter strips the Cookie header and adds no Cookie Manager, leaves every identifier the browser sent as a literal, and stores each asset as its own sampler. State handling, correlation and pruning are still yours.

JMeter does that when the Files Upload tab holds one row with a blank Parameter Name and the Parameters tab is empty. The file's bytes become the body and the row's MIME Type becomes Content-Type.

Only the fields a sampler leaves empty. HTTP Request Defaults supplies server, port, protocol, timeouts, implementation, proxy and the embedded-resource settings, and a value already present on the sampler always wins.

Set httpclient4.auth.preemptive=false in user.properties. The HttpClient4 implementation defaults it to true, so the Authorization header rides on the very first request; with it false, credentials go only after the server sends a challenge.

One numbered variable per row for each named column, plus a row count. For a two-row, three-column select: A_1 and A_2 from column one, C_1 and C_2 from column three, and A_# and C_# both holding 2. The empty entry skips column two.

Number of samples to aggregate sets how many messages one sample result covers. The sampler keeps reading until it has that many or the Timeout expires, and the elapsed time spans the whole batch, not one message.

Grouping decides how requests that arrived close together are laid out: not grouped, separated by a divider controller, wrapped in a Simple Controller, wrapped in a Transaction Controller, or reduced to the first sampler of each group.

The container sample. It starts when the page request started and ends when the last asset finished, so it covers all twenty-one requests. Bytes are summed as well; only Latency still belongs to the page alone.

JMeter's HTTP Cache Manager serves a still-fresh GET out of the thread's own cache without touching the network, and its default cached-resource mode, RETURN_NO_SAMPLE, records no result at all for that hit.

Without a DNS Cache Manager, JMeter resolves the hostname through the JVM's own DNS cache, so every thread reuses the first address that came back. Adding the element gives each thread a private resolution cache instead.

It walks the whole result set and concatenates every row into one tab-separated string as the sample's response data, whether or not Variable Names is filled. Limit ResultSet is the field that caps how many rows it reads.

Check the two correlation checkboxes under Use alternate fields for message correlation. JMeter files each reply under one id and waits on another; if they disagree the reply is discarded and the sample fails with No reply message received.

The chosen TCPClient class. TCPClientImpl stops at the end-of-line byte if one is set, otherwise only when the stream ends. None is set by default, so a server holding the socket open makes every read wait out the response timeout.

The browser has not been given JMeter's generated root CA. Install ApacheJMeterTemporaryRootCA.crt, which the recorder exports into its launch directory the first time it starts, as a trusted authority — and reinstall it once the seven-day validity expires.

JMeter has no single reset: the Cookie, Cache, DNS Cache and Authorization Managers each carry their own per-iteration clearing option. Name the population you are simulating, then set all four deliberately in a plan template.

Decide first what the pool is meant to represent. Leave it at 0 and the thread count alone sets the connections the database sees; pin a positive number and JMeter's own pool becomes the constraint, with waits and, past Max Wait, failed samples.

Work outward from the cheapest hook. A pluggable TCPClient class, a Java Request client class, a scripted sampler and a third-party plugin all reach the protocol. They differ in who maintains the code and how it reaches every injector.

Treat the recorder as a discovery tool, not a source of truth. Let it produce the request sequence and headers, then keep filtering, naming, state and correlation in hand-maintained parts a re-record cannot overwrite.

Set CookieManager.save.cookies=true in bin/user.properties before JMeter starts. Every cookie the manager stores is then written to a thread variable carrying the COOKIE_ prefix, so a cookie named TEST is read as ${COOKIE_TEST}.

Only the Check Return Code checkbox. The sampler always records the process exit code as the response code, but marks the sample successful whatever that code is unless Check Return Code is ticked and the code differs from Expected Return Code.

It limits how many of that one sampler's embedded-resource requests are in flight at once, per execution. It does not limit the shared downloader thread pool, which has no maximum and grows with the number of JMeter threads.

They ignore the SQL Query field completely and only change the connection's state. You place them as separate JDBC Request samplers around other samplers to wrap several statements in one transaction.