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How to know which storage engine is used in MongoDB?
To know which storage engine is used in MongoDB, you can use storageEngine. The syntax is as follows −
db.serverStatus().storageEngine;
To know all the configuration details of storage engine, you can use the following syntax:
db.serverStatus().yourStorageEngineName;
Let us implement the above syntax to know which storage engine is being used in MongoDB. The query is as follows −
> db.serverStatus().storageEngine;
The following is the output −
{
"name" : "wiredTiger",
"supportsCommittedReads" : true,
"supportsSnapshotReadConcern" : true,
"readOnly" : false,
"persistent" : true
}In order to know all configuration details about the above storage engine, the query is as follows −
> db.serverStatus().wiredTiger;
The following is the output displaying configuration details −
{
"uri" : "statistics:",
"LSM" : {
"application work units currently queued" : 0,
"merge work units currently queued" : 0,
"rows merged in an LSM tree" : 0,
"sleep for LSM checkpoint throttle" : 0,
"sleep for LSM merge throttle" : 0,
"switch work units currently queued" : 0,
"tree maintenance operations discarded" : 0,
"tree maintenance operations executed" : 0,
"tree maintenance operations scheduled" : 0,
"tree queue hit maximum" : 0
},
"async" : {
"current work queue length" : 0,
"maximum work queue length" : 0,
"number of allocation state races" : 0,
"number of flush calls" : 0,
"number of operation slots viewed for allocation" : 0,
"number of times operation allocation failed" : 0,
"number of times worker found no work" : 0,
"total allocations" : 0,
"total compact calls" : 0,
"total insert calls" : 0,
"total remove calls" : 0,
"total search calls" : 0,
"total update calls" : 0
},
"block-manager" : {
"blocks pre-loaded" : 173,
"blocks read" : 482,
"blocks written" : 312,
"bytes read" : 2400256,
"bytes written" : 2953216,
"bytes written for checkpoint" : 2953216,
"mapped blocks read" : 0,
"mapped bytes read" : 0
},
"cache" : {
"application threads page read from disk to cache count" : 157,
"application threads page read from disk to cache time (usecs)" : 58747,
"application threads page write from cache to disk count" : 172,
"application threads page write from cache to disk time (usecs)" : 37010,
"bytes belonging to page images in the cache" : 663718,
"bytes belonging to the cache overflow table in the cache" : 182,
"bytes currently in the cache" : 814060,
"bytes dirty in the cache cumulative" : 2673442,
"bytes not belonging to page images in the cache" : 150342,
"bytes read into cache" : 614554,
"bytes written from cache" : 1910375,
"cache overflow cursor application thread wait time (usecs)" : 0,
"cache overflow cursor internal thread wait time (usecs)" : 0,
"cache overflow score" : 0,
"cache overflow table entries" : 0,
"cache overflow table insert calls" : 0,
"cache overflow table remove calls" : 0,
"checkpoint blocked page eviction" : 0,
"eviction calls to get a page" : 546,
"eviction calls to get a page found queue empty" : 547,
"eviction calls to get a page found queue empty after locking" : 0,
"eviction currently operating in aggressive mode" : 0,
"eviction empty score" : 0,
"eviction passes of a file" : 0,
"eviction server candidate queue empty when topping up" : 0,
"eviction server candidate queue not empty when topping up" : 0,
"eviction server evicting pages" : 0,
"eviction server slept, because we did not make progress with eviction" : 367,
"eviction server unable to reach eviction goal" : 0,
"eviction state" : 32,
"eviction walk target pages histogram - 0-9" : 0,
"eviction walk target pages histogram - 10-31" : 0,
"eviction walk target pages histogram - 128 and higher" : 0,
"eviction walk target pages histogram - 32-63" : 0,
"eviction walk target pages histogram - 64-128" : 0,
"eviction walks abandoned" : 0,
"eviction walks gave up because they restarted their walk twice" : 0,
"eviction walks gave up because they saw too many pages and found no candidates" : 0,
"eviction walks gave up because they saw too many pages and found too few candidates" : 0,
"eviction walks reached end of tree" : 0,
"eviction walks started from root of tree" : 0,
"eviction walks started from saved location in tree" : 0,
"eviction worker thread active" : 4,
"eviction worker thread created" : 0,
"eviction worker thread evicting pages" : 2,
"eviction worker thread removed" : 0,
"eviction worker thread stable number" : 0,
"failed eviction of pages that exceeded the in-memory maximum count" : 0,
"failed eviction of pages that exceeded the in-memory maximum time (usecs)" : 0,
"files with active eviction walks" : 0,
"files with new eviction walks started" : 0,
"force re-tuning of eviction workers once in a while" : 0,
"hazard pointer blocked page eviction" : 0,
"hazard pointer check calls" : 2,
"hazard pointer check entries walked" : 0,
"hazard pointer maximum array length" : 0,
"in-memory page passed criteria to be split" : 0,
"in-memory page splits" : 0,
"internal pages evicted" : 0,
"internal pages split during eviction" : 0,
"leaf pages split during eviction" : 0,
"maximum bytes configured" : 4803526656,
"maximum page size at eviction" : 0,
"modified pages evicted" : 2,
"modified pages evicted by application threads" : 0,
"operations timed out waiting for space in cache" : 0,
"overflow pages read into cache" : 0,
"page split during eviction deepened the tree" : 0,
"page written requiring cache overflow records" : 0,
"pages currently held in the cache" : 349,
"pages evicted because they exceeded the in-memory maximum count" : 0,
"pages evicted because they exceeded the in-memory maximum time (usecs)" : 0,
"pages evicted because they had chains of deleted items count" : 0,
"pages evicted because they had chains of deleted items time (usecs)" : 0,
"pages evicted by application threads" : 0,
"pages queued for eviction" : 0,
"pages queued for urgent eviction" : 2,
"pages queued for urgent eviction during walk" : 0,
"pages read into cache" : 324,
"pages read into cache after truncate" : 11,
"pages read into cache after truncate in prepare state" : 0,
"pages read into cache requiring cache overflow entries" : 0,
"pages read into cache requiring cache overflow for checkpoint" : 0,
"pages read into cache skipping older cache overflow entries" : 0,
"pages read into cache with skipped cache overflow entries needed later" : 0,
"pages read into cache with skipped cache overflow entries needed later by checkpoint" : 0,
"pages requested from the cache" : 46897,
"pages seen by eviction walk" : 0,
"pages selected for eviction unable to be evicted" : 0,
"pages walked for eviction" : 0,
"pages written from cache" : 175,
"pages written requiring in-memory restoration" : 0,
"percentage overhead" : 8,
"tracked bytes belonging to internal pages in the cache" : 40080,
"tracked bytes belonging to leaf pages in the cache" : 773980,
"tracked dirty bytes in the cache" : 0,
"tracked dirty pages in the cache" : 0,
"unmodified pages evicted" : 0
},
"connection" : {
"auto adjusting condition resets" : 561,
"auto adjusting condition wait calls" : 42647,
"detected system time went backwards" : 0,
"files currently open" : 170,
"memory allocations" : 277416,
"memory frees" : 266135,
"memory re-allocations" : 23688,
"pthread mutex condition wait calls" : 116127,
"pthread mutex shared lock read-lock calls" : 140031,
"pthread mutex shared lock write-lock calls" : 10159,
"total fsync I/Os" : 760,
"total read I/Os" : 2257,
"total write I/Os" : 875
},
"cursor" : {
"cursor close calls that result in cache" : 482,
"cursor create calls" : 536,
"cursor insert calls" : 296,
"cursor modify calls" : 0,
"cursor next calls" : 2968,
"cursor operation restarted" : 0,
"cursor prev calls" : 212,
"cursor remove calls" : 9,
"cursor reserve calls" : 0,
"cursor reset calls" : 46322,
"cursor search calls" : 27066,
"cursor search near calls" : 441,
"cursor sweep buckets" : 41532,
"cursor sweep cursors closed" : 0,
"cursor sweep cursors examined" : 13338,
"cursor sweeps" : 6922,
"cursor update calls" : 0,
"cursors currently cached" : 170,
"cursors reused from cache" : 312,
"truncate calls" : 0
},
"data-handle" : {
"connection data handles currently active" : 489,
"connection sweep candidate became referenced" : 0,
"connection sweep dhandles closed" : 0,
"connection sweep dhandles removed from hash list" : 207,
"connection sweep time-of-death sets" : 972,
"connection sweeps" : 3469,
"session dhandles swept" : 0,
"session sweep attempts" : 373
},
"lock" : {
"checkpoint lock acquisitions" : 437,
"checkpoint lock application thread wait time (usecs)" : 0,
"checkpoint lock internal thread wait time (usecs)" : 0,
"commit timestamp queue lock application thread time waiting (usecs)" : 0,
"commit timestamp queue lock internal thread time waiting (usecs)" : 0,
"commit timestamp queue read lock acquisitions" : 0,
"commit timestamp queue write lock acquisitions" : 0,
"dhandle lock application thread time waiting (usecs)" : 0,
"dhandle lock internal thread time waiting (usecs)" : 0,
"dhandle read lock acquisitions" : 28619,
"dhandle write lock acquisitions" : 909,
"metadata lock acquisitions" : 116,
"metadata lock application thread wait time (usecs)" : 0,
"metadata lock internal thread wait time (usecs)" : 0,
"read timestamp queue lock application thread time waiting (usecs)" : 0,
"read timestamp queue lock internal thread time waiting (usecs)" : 0,
"read timestamp queue read lock acquisitions" : 0,
"read timestamp queue write lock acquisitions" : 0,
"schema lock acquisitions" : 613,
"schema lock application thread wait time (usecs)" : 0,
"schema lock internal thread wait time (usecs)" : 0,
"table lock application thread time waiting for the table lock (usecs)" : 0,
"table lock internal thread time waiting for the table lock (usecs)" : 0,
"table read lock acquisitions" : 0,
"table write lock acquisitions" : 645,
"txn global lock application thread time waiting (usecs)" : 0,
"txn global lock internal thread time waiting (usecs)" : 0,
"txn global read lock acquisitions" : 375,
"txn global write lock acquisitions" : 354
},
"log" : {
"busy returns attempting to switch slots" : 1,
"force archive time sleeping (usecs)" : 0,
"log bytes of payload data" : 49104,
"log bytes written" : 105216,
"log files manually zero-filled" : 0,
"log flush operations" : 68872,
"log force write operations" : 75951,
"log force write operations skipped" : 75776,
"log records compressed" : 36,
"log records not compressed" : 23,
"log records too small to compress" : 493,
"log release advances write LSN" : 353,
"log scan operations" : 4,
"log scan records requiring two reads" : 3,
"log server thread advances write LSN" : 175,
"log server thread write LSN walk skipped" : 8776,
"log sync operations" : 528,
"log sync time duration (usecs)" : 29656979,
"log sync_dir operations" : 1,
"log sync_dir time duration (usecs)" : 0,
"log write operations" : 552,
"logging bytes consolidated" : 104704,
"maximum log file size" : 104857600,
"number of pre-allocated log files to create" : 2,
"pre-allocated log files not ready and missed" : 1,
"pre-allocated log files prepared" : 2,
"pre-allocated log files used" : 0,
"records processed by log scan" : 636,
"slot close lost race" : 0,
"slot close unbuffered waits" : 0,
"slot closures" : 528,
"slot join atomic update races" : 0,
"slot join calls atomic updates raced" : 0,
"slot join calls did not yield" : 552,
"slot join calls found active slot closed" : 0,
"slot join calls slept" : 0,
"slot join calls yielded" : 0,
"slot join found active slot closed" : 0,
"slot joins yield time (usecs)" : 0,
"slot transitions unable to find free slot" : 0,
"slot unbuffered writes" : 0,
"total in-memory size of compressed records" : 79123,
"total log buffer size" : 33554432,
"total size of compressed records" : 33250,
"written slots coalesced" : 0,
"yields waiting for previous log file close" : 0
},
"perf" : {
"file system read latency histogram (bucket 1) - 10-49ms" : 5,
"file system read latency histogram (bucket 2) - 50-99ms" : 0,
"file system read latency histogram (bucket 3) - 100-249ms" : 0,
"file system read latency histogram (bucket 4) - 250-499ms" : 0,
"file system read latency histogram (bucket 5) - 500-999ms" : 0,
"file system read latency histogram (bucket 6) - 1000ms+" : 0,
"file system write latency histogram (bucket 1) - 10-49ms" : 9,
"file system write latency histogram (bucket 2) - 50-99ms" : 0,
"file system write latency histogram (bucket 3) - 100-249ms" : 0,
"file system write latency histogram (bucket 4) - 250-499ms" : 0,
"file system write latency histogram (bucket 5) - 500-999ms" : 0,
"file system write latency histogram (bucket 6) - 1000ms+" : 0,
"operation read latency histogram (bucket 1) - 100-249us" : 0,
"operation read latency histogram (bucket 2) - 250-499us" : 0,
"operation read latency histogram (bucket 3) - 500-999us" : 44,
"operation read latency histogram (bucket 4) - 1000-9999us" : 20,
"operation read latency histogram (bucket 5) - 10000us+" : 2,
"operation write latency histogram (bucket 1) - 100-249us" : 0,
"operation write latency histogram (bucket 2) - 250-499us" : 0,
"operation write latency histogram (bucket 3) - 500-999us" : 7,
"operation write latency histogram (bucket 4) - 1000-9999us" : 1,
"operation write latency histogram (bucket 5) - 10000us+" : 1
},
"reconciliation" : {
"fast-path pages deleted" : 0,
"page reconciliation calls" : 193,
"page reconciliation calls for eviction" : 1,
"pages deleted" : 18,
"split bytes currently awaiting free" : 0,
"split objects currently awaiting free" : 0
},
"session" : {
"open cursor count" : 22,
"open session count" : 19,
"session query timestamp calls" : 0,
"table alter failed calls" : 0,
"table alter successful calls" : 321,
"table alter unchanged and skipped" : 963,
"table compact failed calls" : 0,
"table compact successful calls" : 0,
"table create failed calls" : 0,
"table create successful calls" : 7,
"table drop failed calls" : 0,
"table drop successful calls" : 0,
"table rebalance failed calls" : 0,
"table rebalance successful calls" : 0,
"table rename failed calls" : 0,
"table rename successful calls" : 0,
"table salvage failed calls" : 0,
"table salvage successful calls" : 0,
"table truncate failed calls" : 0,
"table truncate successful calls" : 0,
"table verify failed calls" : 0,
"table verify successful calls" : 0
},
"thread-state" : {
"active filesystem fsync calls" : 0,
"active filesystem read calls" : 0,
"active filesystem write calls" : 0
},
"thread-yield" : {
"application thread time evicting (usecs)" : 0,
"application thread time waiting for cache (usecs)" : 0,
"connection close blocked waiting for transaction state stabilization" : 0,
"connection close yielded for lsm manager shutdown" : 0,
"data handle lock yielded" : 0,
"get reference for page index and slot time sleeping (usecs)" : 0,
"log server sync yielded for log write" : 0,
"page access yielded due to prepare state change" : 0,
"page acquire busy blocked" : 0,
"page acquire eviction blocked" : 0,
"page acquire locked blocked" : 0,
"page acquire read blocked" : 0,
"page acquire time sleeping (usecs)" : 0,
"page delete rollback time sleeping for state change (usecs)" : 0,
"page reconciliation yielded due to child modification" : 0
},
"transaction" : {
"Number of prepared updates" : 0,
"Number of prepared updates added to cache overflow" : 0,
"Number of prepared updates resolved" : 0,
"commit timestamp queue entries walked" : 0,
"commit timestamp queue insert to empty" : 0,
"commit timestamp queue inserts to head" : 0,
"commit timestamp queue inserts total" : 0,
"commit timestamp queue length" : 0,
"number of named snapshots created" : 0,
"number of named snapshots dropped" : 0,
"prepared transactions" : 0,
"prepared transactions committed" : 0,
"prepared transactions currently active" : 0,
"prepared transactions rolled back" : 0,
"query timestamp calls" : 1,
"read timestamp queue entries walked" : 0,
"read timestamp queue insert to empty" : 0,
"read timestamp queue inserts to head" : 0,
"read timestamp queue inserts total" : 0,
"read timestamp queue length" : 0,
"rollback to stable calls" : 0,
"rollback to stable updates aborted" : 0,
"rollback to stable updates removed from cache overflow" : 0,
"set timestamp calls" : 0,
"set timestamp commit calls" : 0,
"set timestamp commit updates" : 0,
"set timestamp oldest calls" : 0,
"set timestamp oldest updates" : 0,
"set timestamp stable calls" : 0,
"set timestamp stable updates" : 0,
"transaction begins" : 309,
"transaction checkpoint currently running" : 0,
"transaction checkpoint generation" : 117,
"transaction checkpoint max time (msecs)" : 2264,
"transaction checkpoint min time (msecs)" : 4,
"transaction checkpoint most recent time (msecs)" : 43,
"transaction checkpoint scrub dirty target" : 0,
"transaction checkpoint scrub time (msecs)" : 0,
"transaction checkpoint total time (msecs)" : 15771,
"transaction checkpoints" : 116,
"transaction checkpoints skipped because database was clean" : 0,
"transaction failures due to cache overflow" : 0,
"transaction fsync calls for checkpoint after allocating the transaction ID" : 116,
"transaction fsync duration for checkpoint after allocating the transaction ID (usecs)" : 0,
"transaction range of IDs currently pinned" : 0,
"transaction range of IDs currently pinned by a checkpoint" : 0,
"transaction range of IDs currently pinned by named snapshots" : 0,
"transaction range of timestamps currently pinned" : 0,
"transaction range of timestamps pinned by a checkpoint" : 0,
"transaction range of timestamps pinned by the oldest timestamp" : 0,
"transaction sync calls" : 0,
"transactions committed" : 40,
"transactions rolled back" : 269,
"update conflicts" : 0
},
"concurrentTransactions" : {
"write" : {
"out" : 0,
"available" : 128,
"totalTickets" : 128
},
"read" : {
"out" : 1,
"available" : 127,
"totalTickets" : 128
}
}
}
Updated on: 30-Jul-2019
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