Complexity of approximating a function value using queries

I am looking for information on problems of the following kind.

There is a function $ f: [0,1] \to \mathbb{R}$ that is continuous and monotonically-increasing, with $ f(0)<0$ and $ f(1)>0$ . You have to find the unique $ x\in[0,1]$ such that $ f(x)=0$ . You can access $ f$ only through queries of the type "what is $ f(x)$ ?". How many such queries do you need in order to approximate $ x$ up to some constant $ \epsilon$ ?

Here, the solution is simple: using binary search, the interval in which $ x$ can lie shrinks by 2 after each query, so $ \log_2(1/\epsilon)$ queries are sufficient. This is also an upper bound, since an adversary can always answer in such a way that the possible interval for $ x$ shrinks by at most 2 after each query.

However, one can think of more complicated problems of this kind, with several different functions and possibly different kinds of queries.

What is a term, and some references, for this kind of computational problems?

What is the suitable file structure for database if queries are select (relational algebra) operations only?

Searches related to A relation R(A, B, C, D) has to be accessed under the query σB=10(R). Out of the following possible file structures, which one should be chosen and why? i. R is a heap file. ii. R has a clustered hash index on B. iii. R has an unclustered B+ tree index on (A, B).

Multiple queries in phpmyadmin – Distance using coordinates, Slope, Intercept, Angle, and few more

I having around 500 excel sheets in .csv format with data captured for my experiment having following columns in place.

enter image description here

Now I need to calculate the following parameters using this data. I have done these in excel, however doing this repeatedly for each excel so many times is difficult, so I want to write an SQL query in PhpmyAdmin will help some time.

  1. Last charecter typed – need to capture last charecter from the column ‘CharSq’
  2. *Slope (in column J) =(B3-B2)/(A3-A2)
  3. Intercept (in column K) =B2-(A2*(J3))
  4. Angle (in degrees) =MOD(DEGREES(ATAN2((A3-A2),(B3-B2))), 360) –
  5. Index of Difficulty =LOG(((E1/7.1)+1),2)
  6. Speed Value length (if speed value length >3, then mark as 1 or else 0) = =IF(LEN(D3) >= 3, "1","0")
  7. Wrong Sequence (if I3=I2,then mark search time, else actual time) =IF(I3=I2,"Search Time","Actual Time")
  8. Mark charecter into (1,2,3) = =IF(I2="A",1, IF(I2="B",2, IF(I2="C",3, 0))) enter image description here

I have started with this SQL query SELECT id, type, charSq, substr(charSq,-1,1) AS TypedChar, xCoordinate, yCoordinate, angle, distance, timestamp, speed FROM table 1 WHERE 1

Need help for the rest of the parameters. Thanks.

Note – I am going to run this in phpMyAdmin SQL

Batching multiple nearest surface queries: Is it faster? Are there better algorithms?

I’m working on an algorithm that computes lots of "nearest point on a triangulated surface" queries in 3d as a way to resample data sets, and I’m wondering if there is any information out there on speeding up these queries. My gut tells me that partitioning the set of query points in a voxel grid or something, and doing them in batches could be a speedup, but I can’t quite see how I could efficiently use that. Also I’m not sure if the time cost of partitioning would balance the search speedup. Is running N independent queries really the best way?

I found that there are papers and research for the all-knn algorithm, but that’s for searching within a single set. And then, those speedups take advantage of the previously computed neighbors or structure within the single set, so I can’t use them. It feels close though.

Any help is appreciated.

I am unable to understand the logic behind the code (I’ve added exact queries as comments in the code)

Our local ninja Naruto is learning to make shadow-clones of himself and is facing a dilemma. He only has a limited amount of energy (e) to spare that he must entirely distribute among all of his clones. Moreover, each clone requires at least a certain amount of energy to function (m) . Your job is to count the number of different ways he can create shadow clones. Example:

e=7;m=2

ans = 4

The following possibilities occur: Make 1 clone with 7 energy

Make 2 clones with 2, 5 energy

Make 2 clones with 3, 4 energy

Make 3 clones with 2, 2, 3 energy.

Note: <2, 5> is the same as <5, 2>. Make sure the ways are not counted multiple times because of different ordering.

Answer

int count(int n, int k){     if((n<k)||(k<1)) return 0;     else if ((n==k)||(k==1)) return 1;     else return count(n-1,k-1)+ count(n-k,k);   // logic behind this? }  int main() {     int e,m;            // e is total energy and m is min energy per clone     scanf("%d %d", &e, &m);     int max_clones= e/m;     int i,ans=0;     for(i=1;i<=max_clones;i++){         int available = e - ((m-1)*i);   // why is it (m-1)*i instead of m*i         ans += count(available, i);     }     return 0; } 

Slow Database with concurrent queries, Table cache hitrate 0% [Newbie! Need help :)]

I’m a bit of a newbie when it comes to dba work so please take it easy!

I have gone through countless threads trying to improve the performance of my database, looking for someone who could give me some pointers on changes I may need to do for my variables that may squeeze more performance. Or if I have misconfigured anything.

Here are the details Server specs: E3 1270 V6 w/32gb Ram OS: Windows Server 2016 Mysql Version: 8.0.19 – MySQL Community Server – GPL

MYSQL Config https://ybin.me/p/b99f994ad62c27ad#zvwS1+XGP6ZIZtKYdiMOySg+aYR85Qp3ciTvFr6q4mE=

Show Global Status (during high usage):

https://ybin.me/p/b74fae252e807749#F9+88tWsVo/hqHjKlnlnG1gEUwj7vlonLlYrUxXnThg=

SHOW ENGINE INNODB STATUS (During High Usage)

InnoDB       ===================================== 2020-05-17 16:57:16 0xa6c INNODB MONITOR OUTPUT ===================================== Per second averages calculated from the last 7 seconds ----------------- BACKGROUND THREAD ----------------- srv_master_thread loops: 103908 srv_active, 0 srv_shutdown, 300397 srv_idle srv_master_thread log flush and writes: 0 ---------- SEMAPHORES ---------- OS WAIT ARRAY INFO: reservation count 42855 OS WAIT ARRAY INFO: signal count 37923 RW-shared spins 3053, rounds 3116, OS waits 59 RW-excl spins 6909, rounds 59455, OS waits 1320 RW-sx spins 99, rounds 1306, OS waits 25 Spin rounds per wait: 1.02 RW-shared, 8.61 RW-excl, 13.19 RW-sx ------------------------ LATEST DETECTED DEADLOCK ------------------------ 2020-05-17 13:52:00 0x2904 *** (1) TRANSACTION: TRANSACTION 12175899, ACTIVE 0 sec starting index read mysql tables in use 3, locked 3 LOCK WAIT 4 lock struct(s), heap size 1136, 3 row lock(s) MySQL thread id 3340, OS thread handle 3660, query id 2398670 localhost 127.0.0.1 root updating UPDATE user_inventory SET count = 22 WHERE identifier = 'steam:11000013f8eef2a' AND item = 'bandage'  *** (1) HOLDS THE LOCK(S): RECORD LOCKS space id 584 page no 84 n bits 336 index PRIMARY of table `essentialmode`.`user_inventory` trx id 12175899 lock_mode X locks rec but not gap Record lock, heap no 69 PHYSICAL RECORD: n_fields 6; compact format; info bits 0  0: len 4; hex 8039a49f; asc  9  ;;  1: len 6; hex 000000b9849a; asc       ;;  2: len 7; hex 02000001ad0151; asc       Q;;  3: len 21; hex 737465616d3a313130303030313366386565663261; asc steam:11000013f8eef2a;;  4: len 7; hex 62616e64616765; asc bandage;;  5: len 4; hex 8000002b; asc    +;;   *** (1) WAITING FOR THIS LOCK TO BE GRANTED: RECORD LOCKS space id 584 page no 2445 n bits 792 index item of table `essentialmode`.`user_inventory` trx id 12175899 lock_mode X waiting Record lock, heap no 561 PHYSICAL RECORD: n_fields 2; compact format; info bits 0  0: len 7; hex 62616e64616765; asc bandage;;  1: len 4; hex 800002e8; asc     ;;   *** (2) TRANSACTION: TRANSACTION 12175886, ACTIVE 0 sec fetching rows mysql tables in use 3, locked 3 LOCK WAIT 60 lock struct(s), heap size 8400, 2334 row lock(s) MySQL thread id 3336, OS thread handle 10296, query id 2398648 localhost 127.0.0.1 root updating UPDATE user_inventory SET count = 4 WHERE identifier = 'steam:11000010e1c050e' AND item = 'bandage'  *** (2) HOLDS THE LOCK(S): RECORD LOCKS space id 584 page no 2445 n bits 792 index item of table `essentialmode`.`user_inventory` trx id 12175886 lock_mode X Record lock, heap no 1 PHYSICAL RECORD: n_fields 1; compact format; info bits 0  0: len 8; hex 73757072656d756d; asc supremum;;  Record lock, heap no 561 PHYSICAL RECORD: n_fields 2; compact format; info bits 0  0: len 7; hex 62616e64616765; asc bandage;;  1: len 4; hex 800002e8; asc     ;;   *** (2) WAITING FOR THIS LOCK TO BE GRANTED: RECORD LOCKS space id 584 page no 84 n bits 336 index PRIMARY of table `essentialmode`.`user_inventory` trx id 12175886 lock_mode X locks rec but not gap waiting Record lock, heap no 69 PHYSICAL RECORD: n_fields 6; compact format; info bits 0  0: len 4; hex 8039a49f; asc  9  ;;  1: len 6; hex 000000b9849a; asc       ;;  2: len 7; hex 02000001ad0151; asc       Q;;  3: len 21; hex 737465616d3a313130303030313366386565663261; asc steam:11000013f8eef2a;;  4: len 7; hex 62616e64616765; asc bandage;;  5: len 4; hex 8000002b; asc    +;;  *** WE ROLL BACK TRANSACTION (1) ------------ TRANSACTIONS ------------ Trx id counter 12207888 Purge done for trx's n:o < 12207888 undo n:o < 0 state: running but idle History list length 19 LIST OF TRANSACTIONS FOR EACH SESSION: ---TRANSACTION 283609840283040, not started 0 lock struct(s), heap size 1136, 0 row lock(s) ---TRANSACTION 283609840282192, not started 0 lock struct(s), heap size 1136, 0 row lock(s) ---TRANSACTION 283609840281344, not started 0 lock struct(s), heap size 1136, 0 row lock(s) -------- FILE I/O -------- I/O thread 0 state: wait Windows aio (insert buffer thread) I/O thread 1 state: wait Windows aio (log thread) I/O thread 2 state: wait Windows aio (read thread) I/O thread 3 state: wait Windows aio (read thread) I/O thread 4 state: wait Windows aio (read thread) I/O thread 5 state: wait Windows aio (read thread) I/O thread 6 state: wait Windows aio (read thread) I/O thread 7 state: wait Windows aio (read thread) I/O thread 8 state: wait Windows aio (read thread) I/O thread 9 state: wait Windows aio (read thread) I/O thread 10 state: wait Windows aio (read thread) I/O thread 11 state: wait Windows aio (read thread) I/O thread 12 state: wait Windows aio (read thread) I/O thread 13 state: wait Windows aio (read thread) I/O thread 14 state: wait Windows aio (read thread) I/O thread 15 state: wait Windows aio (read thread) I/O thread 16 state: wait Windows aio (read thread) I/O thread 17 state: wait Windows aio (read thread) I/O thread 18 state: wait Windows aio (read thread) I/O thread 19 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(write thread) I/O thread 77 state: wait Windows aio (write thread) I/O thread 78 state: wait Windows aio (write thread) I/O thread 79 state: wait Windows aio (write thread) I/O thread 80 state: wait Windows aio (write thread) I/O thread 81 state: wait Windows aio (write thread) I/O thread 82 state: wait Windows aio (write thread) I/O thread 83 state: wait Windows aio (write thread) I/O thread 84 state: wait Windows aio (write thread) I/O thread 85 state: wait Windows aio (write thread) I/O thread 86 state: wait Windows aio (write thread) I/O thread 87 state: wait Windows aio (write thread) I/O thread 88 state: wait Windows aio (write thread) I/O thread 89 state: wait Windows aio (write thread) I/O thread 90 state: wait Windows aio (write thread) I/O thread 91 state: wait Windows aio (write thread) I/O thread 92 state: wait Windows aio (write thread) I/O thread 93 state: wait Windows aio (write thread) I/O thread 94 state: wait Windows aio (write thread) I/O thread 95 state: wait 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thread 114 state: wait Windows aio (write thread) I/O thread 115 state: wait Windows aio (write thread) I/O thread 116 state: wait Windows aio (write thread) I/O thread 117 state: wait Windows aio (write thread) I/O thread 118 state: wait Windows aio (write thread) I/O thread 119 state: wait Windows aio (write thread) I/O thread 120 state: wait Windows aio (write thread) I/O thread 121 state: wait Windows aio (write thread) I/O thread 122 state: wait Windows aio (write thread) I/O thread 123 state: wait Windows aio (write thread) I/O thread 124 state: wait Windows aio (write thread) I/O thread 125 state: wait Windows aio (write thread) I/O thread 126 state: wait Windows aio (write thread) I/O thread 127 state: wait Windows aio (write thread) I/O thread 128 state: wait Windows aio (write thread) I/O thread 129 state: wait Windows aio (write thread) Pending normal aio reads: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] , aio writes: [0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0] ,  ibuf aio reads:, log i/o's:, sync i/o's: Pending flushes (fsync) log: 0; buffer pool: 0 25639 OS file reads, 5252794 OS file writes, 2142145 OS fsyncs 0.00 reads/s, 0 avg bytes/read, 0.00 writes/s, 0.00 fsyncs/s ------------------------------------- INSERT BUFFER AND ADAPTIVE HASH INDEX ------------------------------------- Ibuf: size 1, free list len 30, seg size 32, 78 merges merged operations:  insert 89, delete mark 3, delete 0 discarded operations:  insert 0, delete mark 0, delete 0 Hash table size 4425293, node heap has 577 buffer(s) Hash table size 4425293, node heap has 7 buffer(s) Hash table size 4425293, node heap has 3 buffer(s) Hash table size 4425293, node heap has 42 buffer(s) Hash table size 4425293, node heap has 25 buffer(s) Hash table size 4425293, node heap has 8 buffer(s) Hash table size 4425293, node heap has 117 buffer(s) Hash table size 4425293, node heap has 268 buffer(s) 63.71 hash searches/s, 4.29 non-hash searches/s --- LOG --- Log sequence number          8204611911 Log buffer assigned up to    8204611911 Log buffer completed up to   8204611911 Log written up to            8204611911 Log flushed up to            8204611911 Added dirty pages up to      8204611911 Pages flushed up to          8204611911 Last checkpoint at           8204611911 2113740 log i/o's done, 0.00 log i/o's/second ---------------------- BUFFER POOL AND MEMORY ---------------------- Total large memory allocated 17582522368 Dictionary memory allocated 1618261 Buffer pool size   1048576 Free buffers       1010227 Database pages     37302 Old database pages 13779 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 1961, not young 12509 0.00 youngs/s, 0.00 non-youngs/s Pages read 25245, created 12063, written 2341874 0.00 reads/s, 0.00 creates/s, 0.00 writes/s Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000 Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 37302, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---------------------- INDIVIDUAL BUFFER POOL INFO ---------------------- ---BUFFER POOL 0 Buffer pool size   131072 Free buffers       126195 Database pages     4738 Old database pages 1766 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 47, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 3177, created 1561, written 390400 0.00 reads/s, 0.00 creates/s, 0.00 writes/s Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000 Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 4738, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 1 Buffer pool size   131072 Free buffers       126202 Database pages     4747 Old database pages 1732 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 57, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 3144, created 1603, written 377393 0.00 reads/s, 0.00 creates/s, 0.00 writes/s Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000 Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 4747, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 2 Buffer pool size   131072 Free buffers       126359 Database pages     4584 Old database pages 1682 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 1596, not young 12509 0.00 youngs/s, 0.00 non-youngs/s Pages read 3159, created 1431, written 286695 0.00 reads/s, 0.00 creates/s, 0.00 writes/s No buffer pool page gets since the last printout Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 4584, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 3 Buffer pool size   131072 Free buffers       126376 Database pages     4563 Old database pages 1679 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 23, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 3060, created 1503, written 217282 0.00 reads/s, 0.00 creates/s, 0.00 writes/s No buffer pool page gets since the last printout Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 4563, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 4 Buffer pool size   131072 Free buffers       126427 Database pages     4515 Old database pages 1683 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 39, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 3113, created 1402, written 296757 0.00 reads/s, 0.00 creates/s, 0.00 writes/s Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000 Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 4515, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 5 Buffer pool size   131072 Free buffers       126346 Database pages     4604 Old database pages 1681 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 48, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 3120, created 1484, written 220370 0.00 reads/s, 0.00 creates/s, 0.00 writes/s Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000 Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 4604, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 6 Buffer pool size   131072 Free buffers       126053 Database pages     4883 Old database pages 1815 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 104, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 3276, created 1607, written 259821 0.00 reads/s, 0.00 creates/s, 0.00 writes/s Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000 Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 4883, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] ---BUFFER POOL 7 Buffer pool size   131072 Free buffers       126269 Database pages     4668 Old database pages 1741 Modified db pages  0 Pending reads      0 Pending writes: LRU 0, flush list 0, single page 0 Pages made young 47, not young 0 0.00 youngs/s, 0.00 non-youngs/s Pages read 3196, created 1472, written 293156 0.00 reads/s, 0.00 creates/s, 0.00 writes/s Buffer pool hit rate 1000 / 1000, young-making rate 0 / 1000 not 0 / 1000 Pages read ahead 0.00/s, evicted without access 0.00/s, Random read ahead 0.00/s LRU len: 4668, unzip_LRU len: 0 I/O sum[0]:cur[0], unzip sum[0]:cur[0] -------------- ROW OPERATIONS -------------- 0 queries inside InnoDB, 0 queries in queue 0 read views open inside InnoDB Process ID=9652, Main thread ID=00000000000028B4 , state=sleeping Number of rows inserted 425605, updated 1126794, deleted 24758, read 3734292042 0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 0.00 reads/s Number of system rows inserted 1841, updated 1056, deleted 1656, read 1362568 0.00 inserts/s, 0.00 updates/s, 0.00 deletes/s, 69.28 reads/s ---------------------------- END OF INNODB MONITOR OUTPUT ============================ 

MYSQL Tuner Tips https://i.gyazo.com/107f94f2e69fafe58d6f2125ff3c9ccc.png

I would highly appreciate any input on how we can make the database happier! If I’m missing any information, let me know happy to provide any extra info!

Is there a way to group often used tables and queries in SSMS?

I am not a DBA by training, but due to role shifts I am having to modify and maintain tables and stored procedures fairly often. I would like to visually group tables and stored procedures together in a sort of shortcuts folder. So that when I need to open several related views I don’t have to scroll all over the database. Is something like this possible?

Sorry if this is a dumb question. I am just trying to make this part of my job a little less tedious.

Given two arrays A and B, how do I answer queries asking the qth minimum sum of A[i]+B[j]?

I am given two arrays A and B of same size K (K<=20000). There can be upto 500 queries (offline), each asking the qth minimum sum a+b such that a belongs to A and b belongs to B (q<=10000). How do I answer these queries efficiently?
One way would be to iterate over all pairs but that is too slow for me.

How can I rearrange these two queries to get the second column from inside the IN()

How can I get the random.id column from inside this first select

select id, name from random where id IN(1,2,3,4); +----+-----------+ | id | name      | +----+-----------+ |  1 | Frank     | |  2 | Tracey    | |  3 | Bos       | |  4 | Charlotte | +----+-----------+  select `where`, `who`, COUNT(*) from cards where who = "." OR who IN(select name from random where id IN(1,2,3,4)) GROUP BY `who`, `where`; +-------+--------+----------+ | where | who    | COUNT(*) | +-------+--------+----------+ | pack  | .      |       78 | | hand  | Frank  |       15 | | hand  | Tracey |       15 | |       | .      |       20 | +-------+--------+----------+ 4 rows in set (0.00 sec) 

out when using the second more complicated select, above. Both tables have more columns than show and I do not want to add an extra row to the random table simply to define the . as comes out of the cards table. I think it should be possible to rearrange the second query to provide the desired output of where, id, count but sadly it eludes me.

How can we correlate linked server queries running to their source instance?

We have multiple versions of SQL Server from 2008R2 (I know) to 2016. There are many linked server queries. I’m trying to build a tool that will tell me the queries executing on a target server that come from linked server queries executing on another source server.

QUESTION #1)

Can I rely on sys.dm_exec_sessions.program_name = ‘Microsoft SQL Server’?

I’ve hesitated to go that route so far and have been relying on looking at the sql text:

dest.text LIKE '%"Tbl[0-9][0-9][0-9][0-9]"%' 

QUESTION #2)

Once I have found the linked server queries running on my target instance, I want to traverse back to the original calling instance. Is there an easy way to do this?

Right now, I’m heading down the path of looking for the target instance in the sql text of queries running on the source host(s):

AND dest.text LIKE '%$  LinkedServerName%' 

(Not the variable expansion – this is a powershell snippet, not straight TSQL)

Still, I may have some interesting logic to truly say, “This query is what is causing the query to execute on my linked server” – not to mention the perf hit of the leading wildcard search into my sql text.

Ideas?

Thank you,

-Peter