01e9fd6d0e
When a $planCacheStats pipeline is delivered to a mongos, it will be forwarded to one host in each shard following the normal host targeting rules for aggregate operations. Each of the documents returned to the client will be augmented with "shard" and "host" fields, giving the name of the shard and the host:port string from which the plan cache metadata originated. Allowing clients to collect plan cache information from every shardsvr in the cluster is left as future work.
135 lines
5.4 KiB
JavaScript
135 lines
5.4 KiB
JavaScript
// Test clearing of the plan cache, either manually through the planCacheClear command,
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// or due to system events such as an index build.
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//
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// @tags: [
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// # This test attempts to perform queries and introspect/manipulate the server's plan cache
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// # entries. The former operation may be routed to a secondary in the replica set, whereas the
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// # latter must be routed to the primary.
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// # If all chunks are moved off of a shard, it can cause the plan cache to miss commands.
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// assumes_read_preference_unchanged,
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// assumes_read_concern_unchanged,
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// does_not_support_stepdowns,
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// assumes_balancer_off,
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// assumes_unsharded_collection,
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// # Sharding support for $planCacheStats requires all nodes to be binary version 4.4.
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// requires_fcv_44,
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// ]
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(function() {
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const coll = db.jstests_plan_cache_clear;
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coll.drop();
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function numPlanCacheEntries() {
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return coll.aggregate([{$planCacheStats: {}}]).itcount();
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}
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function dumpPlanCacheState() {
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return coll.aggregate([{$planCacheStats: {}}]).toArray();
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}
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assert.commandWorked(coll.insert({a: 1, b: 1}));
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assert.commandWorked(coll.insert({a: 1, b: 2}));
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assert.commandWorked(coll.insert({a: 2, b: 2}));
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// We need two indices so that the MultiPlanRunner is executed.
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assert.commandWorked(coll.createIndex({a: 1}));
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assert.commandWorked(coll.createIndex({a: 1, b: 1}));
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// Run a query so that an entry is inserted into the cache.
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assert.eq(1, coll.find({a: 1, b: 1}).itcount());
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// Invalid key should be a no-op.
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assert.commandWorked(coll.runCommand('planCacheClear', {query: {unknownfield: 1}}));
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assert.eq(1, numPlanCacheEntries(), dumpPlanCacheState());
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// Introduce a second plan cache entry.
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assert.eq(0, coll.find({a: 1, b: 1, c: 1}).itcount());
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assert.eq(2, numPlanCacheEntries(), dumpPlanCacheState());
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// Drop one of the two shapes from the cache.
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assert.commandWorked(coll.runCommand('planCacheClear', {query: {a: 1, b: 1}}),
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dumpPlanCacheState());
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assert.eq(1, numPlanCacheEntries(), dumpPlanCacheState());
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// Drop the second shape from the cache.
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assert.commandWorked(coll.runCommand('planCacheClear', {query: {a: 1, b: 1, c: 1}}),
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dumpPlanCacheState());
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assert.eq(0, numPlanCacheEntries(), dumpPlanCacheState());
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// planCacheClear can clear $expr queries.
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assert.eq(1, coll.find({a: 1, b: 1, $expr: {$eq: ['$a', 1]}}).itcount());
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assert.eq(1, numPlanCacheEntries(), dumpPlanCacheState());
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assert.commandWorked(
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coll.runCommand('planCacheClear', {query: {a: 1, b: 1, $expr: {$eq: ['$a', 1]}}}));
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assert.eq(0, numPlanCacheEntries(), dumpPlanCacheState());
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// planCacheClear fails with an $expr query with an unbound variable.
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assert.commandFailed(
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coll.runCommand('planCacheClear', {query: {a: 1, b: 1, $expr: {$eq: ['$a', '$$unbound']}}}));
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// Insert two more shapes into the cache.
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assert.eq(1, coll.find({a: 1, b: 1}).itcount());
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assert.eq(1, coll.find({a: 1, b: 1}, {_id: 0, a: 1}).itcount());
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assert.eq(2, numPlanCacheEntries(), dumpPlanCacheState());
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// Error cases.
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assert.commandFailedWithCode(coll.runCommand('planCacheClear', {query: 12345}),
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ErrorCodes.BadValue);
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assert.commandFailedWithCode(coll.runCommand('planCacheClear', {query: /regex/}),
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ErrorCodes.BadValue);
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assert.commandFailedWithCode(coll.runCommand('planCacheClear', {query: {a: {$no_such_op: 1}}}),
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ErrorCodes.BadValue);
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// 'sort' parameter is not allowed without 'query' parameter.
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assert.commandFailedWithCode(coll.runCommand('planCacheClear', {sort: {a: 1}}),
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ErrorCodes.BadValue);
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// 'projection' parameter is not allowed with 'query' parameter.
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assert.commandFailedWithCode(coll.runCommand('planCacheClear', {projection: {_id: 0, a: 1}}),
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ErrorCodes.BadValue);
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// Drop query cache. This clears all cached queries in the collection.
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assert.commandWorked(coll.runCommand('planCacheClear'));
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assert.eq(0, numPlanCacheEntries(), dumpPlanCacheState());
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// Clearing the plan cache for a non-existent collection should succeed.
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const nonExistentColl = db.plan_cache_clear_nonexistent;
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nonExistentColl.drop();
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assert.commandWorked(nonExistentColl.runCommand('planCacheClear'));
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//
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// Query Plan Revision
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// http://docs.mongodb.org/manual/core/query-plans/#query-plan-revision
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// As collections change over time, the query optimizer deletes the query plan and re-evaluates
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// after any of the following events:
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// - The reIndex rebuilds the index.
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// - You add or drop an index.
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// - The mongod process restarts.
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//
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// Case 1: The reIndex rebuilds the index.
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// Steps:
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// Populate the cache with 1 entry.
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// Run reIndex on the collection.
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// Confirm that cache is empty.
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const isMongos = db.adminCommand({isdbgrid: 1}).isdbgrid;
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if (!isMongos) {
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assert.eq(1, coll.find({a: 1, b: 1}).itcount());
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assert.eq(1, numPlanCacheEntries(), dumpPlanCacheState());
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assert.commandWorked(coll.reIndex());
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assert.eq(0, numPlanCacheEntries(), dumpPlanCacheState());
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}
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// Case 2: You add or drop an index.
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// Steps:
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// Populate the cache with 1 entry.
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// Add an index.
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// Confirm that cache is empty.
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assert.eq(1, coll.find({a: 1, b: 1}).itcount());
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assert.eq(1, numPlanCacheEntries(), dumpPlanCacheState());
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assert.commandWorked(coll.createIndex({b: 1}));
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assert.eq(0, numPlanCacheEntries(), dumpPlanCacheState());
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// Case 3: The mongod process restarts
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// Not applicable.
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})();
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