java - H2 database keeps growing: How to analyze the output of the Recover tool? -

-

we use h2 long running process stores many short-lived “events” embedded h2 database. there’s high throughput of rows being inserted , deleted, frequency of events varies.

on semi-productive system database file had grown 27 gib. after compacting thoroughly, file has 1.25 mib. that’s factor >20000!

i understand h2 not compact during runtime mark , reuse free space , think should ok. @ point there should balance between used , free space , database file should not need grow further.

h2’s recover tool recommended analyze such situations (with switch -transactionlog). how interpret output of recover tool?

first of all, statistics section @ bottom:

---- statistics ---- -- page count: 14147341, free: 14106216 -- page data bytes: head 612539, empty 20613944, rows 9040909 (32% full) -- free 99%, 14108082 page(s) -- data leaf 0%, 14779 page(s) -- data node 0%, 241 page(s) -- btree leaf 0%, 2644 page(s) -- btree node 0%, 564 page(s) -- free list 0%, 865 page(s) -- stream trunk 0%, 39 page(s) -- stream data 0%, 20124 page(s)

the free page count shows space taken free pages (default page size of 2 kib).

stream data 20124 pages means 40 mib used transaction log, right?

next question lobs. in recover output there 13342 insert statements information_schema.lob_data. when open database in console, table has 2 rows. why difference?

the usual suspect uncommitted transactions. looking @ code autocommit never switched off, want check anyway. recover output has 702431 rows of transaction log. looks lot me? normal? how recognize uncommitted transactions? first few lines this:

---- transaction log ---- -- log 164481:8670836 next: 8673913 -- log 164481:8670836/8672265 -- undo page 34939 data leaf (last) -- undo page 32723 free list  -- undo page 8590631 data node  -- log 164481:8670836/8672266 -- undo page 42949 data node  -- undo page 6686382 data node  -- undo page 44 data node  -- session 1 table 10 - 61593342 delete information_schema.lob_data _rowid_ = 61593342; -- commit 1 -- undo page 111 b-tree leaf (last) -- log 164481:8670836/8672267 -- undo page 62 b-tree node (last) -- log 164481:8670836/8672268 -- undo page 3566625 b-tree node (last) -- undo page 48 b-tree node (last) -- undo page 8590604 data leaf (last) -- log 164481:8670836/8672269 -- undo page 42802 data node  -- undo page 8187925 data node  -- undo page 49 data node  -- session 1 table 2 - 48272953 delete information_schema.lobs _rowid_ = 48272953; -- commit 1

aren’t 2 committed successfully? why still in log?

the h2 version 1.3.163. have tried 1.3.176 artificial events, file grew fast in same way.

these questions related, didn’t me:

for file have analyzed, 99% of pages free: free 99%, 14108082 page(s). guess 99% of data removed (tables truncated, tables dropped, indexes dropped, lobs removed, transaction log truncated, temporary tables removed, , on). therefore, analyzing this file not help.

what interesting analyze file before 99% became free. that, example copy file while program running, using built-in backup feature (sql statement backup ...). , analyze file (run recover tool on file). may need multiple times, until find place 99% of file not yet free.


Comments

Post a Comment

Popular posts from this blog

matlab - "Contour not rendered for non-finite ZData" -

-
i'm trying plot frequency characteristic equation using ezplot, matlab gives following warning, "contour not rendered non-finite zdata". have used command plot frequency equations warning , plot display empty , not change axis range well. can please help. appreciated. here's code i'm using. % transfer matrix case-i, thin rotor clear all; clc; ei = 1626; l = 0.15; m = 0.44108; = 2.178*10^-4; i_p = 2.205*10^-5; itr = 0.24; i_pr = 0.479; syms p n; f = [1 l*1i l^2/(2*ei)*1i l^3/(6*ei); 0 1 l/ei -l^2/(2*ei)*1i; 0 0 1 -l*1i; 0 0 0 l]; p = [ 1 0 0 0; 0 1 0 0; 0 -it*p^2+i_p*n*p 1 0; -m*p^2 0 0 1]; p_r = [1 0 0 0; 0 1 0 0; 0 -itr*p^2+i_pr*n*p 1 0; -m*p^2 0 0 1]; = f*p*f*p*f*p*f; b = p_r*f*p*f*p*f; r = a(1,2)/a(1,4); a12_p = 0; a22_p = a(2,2)-r*a(2,4); a32_p = a(3,2)-r*a(3,4); a42_p = a(4,2)-r*a(4,4); ap(2,2) = a22_p; ap(3,2) = a32_p; ap(4,2) = a42_p; ap(4,4) = 1; c = b*ap; m = [c(3,2) c(3,4); c(4,2) c(4,...
Read more

delphi - Indy UDP Read Contents of Adata -

-
i using indy udp server read string of data. however, not know how work adata parameter. can around converting binary using bytetobin function below , convert hex using bintohex1 . feel stupid , works slow. know how can directly results without 2 conversions? thanks!! here codes: procedure tform1.idudpserver1udpread(athread: tidudplistenerthread; const adata: tidbytes; abinding: tidsockethandle); var buf: tidbytes; buffer: string; data_received: string; begin if bytestostring(adata) <> 'hello' begin buffer := hextostring('00'); setlength(buf, length(buffer)); copytidstring(buffer, buf, 0); abinding.sendto(abinding.peerip, abinding.peerport, buf); data_received := bintohex1(bytetobin(adata[1]) + bytetobin(adata[2]) + bytetobin(adata[3]) + bytetobin(adata[4]) + bytetobin(adata[5]) + bytetobin(adata[6]) + bytetobin(adata[7]) + bytetobin(adata[8]) + bytetobin(adata[9]) + bytetobin(adata[10]) + bytetobin(adata[11...
Read more

javascript - Any ideas when Firefox is likely to implement lengthAdjust and textLength? -

-
any ideas when firefox implement lengthadjust andtextlength?..... working svg application. lengthadjust , textlength working fine in chrome not working in fire fox . <svg viewbox = "0 0 500 300" version = "1.1"> <defs> <path id="s3" d="m 10,90 q 100,15 200,70" /> </defs> <g> <text font-size = "20"> <textpath xlink:href="#s3" textlength="205"> short text</textpath> </text> <use xlink:href="#s3" fill="none" stroke="black" stroke-width="1"/> </g> </svg> this implemented in firefox text elements (not textpath or tspan) in case that's ok though can move attribute text element. <svg viewbox = "0 0 500 300" version = "1.1"> <defs> ...
Read more