What is a Database Environment?

I am going through Relational Database Design by JLM. I have come across words like
database, data model, DBMS etc. which I am able to understand. But, I get confused when the author tries to use Database and Database Environment with supposedly different meaning (as per my understanding).
What does Database Environment make up ? I understand that data model defines relationship of the data whereas DBMS is data model specific and translated data manipulation requests and retrieves data from physical storage device(s). The author defined Database
as data and its relationship.
Where does Environment come into picture ?
This is where I got confused : underlying relationships in a database environment are independent of the data model and therefore also independent of the DBMS you are using
BTW Am I reading the right book to start with, considering am just beginning?

Both Strike Developer and EngSoonChea, its quite interesting to see that when ever Strike developer asks question nobody else but only EngSoonCheah is getting answers marked. I dont think this is mere co incidence
I can see all threads created by Strikedeveloper and only marked answer is by EngSoonCheah. Please make sure favoritism is marking answer is not allowed by Microsoft and both of you could be banned from entering forums.
Please mark this reply as answer if it solved your issue or vote as helpful if it helped so that other forum members can benefit from it
My Technet Wiki Article
MVP

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Infinite loop during recovery of JE 4.1.10 database environment

Hi there,
We have a JE 4.1.10 database environment which is over 20GB in size. In order to improve performance we increased je.log.fileCacheSize so that we could cache all of the 10MB DB log file descriptors in memory and prevent JE from having to constantly open/close log files (the environment is only partially cached in memory and there are more than 2000 log files). Unfortunately, we failed to increase the file descriptor ulimit from the Linux default of 1024 and our application failed when the ulimit was reached.
Since then we've reverted the settings and increased the JVM heap size so that we can fully cache everything in memory again. However, we are having problems recovering the DB environment. It looks like the environment recovery proceeds through the 10 recovery steps but gets stuck while loading the log file utilization meta-data:
Stack trace #1:
"main" prio=10 tid=0x000000005622f000 nid=0x5d94 runnable [0x00000000419fe000]
java.lang.Thread.State: RUNNABLE
     at java.io.RandomAccessFile.seek(Native Method)
     at com.sleepycat.je.log.FileManager.readFromFileInternal(FileManager.java:1605)
     - locked <0x00002aaaf80dca88> (a com.sleepycat.je.log.FileManager$1)
     at com.sleepycat.je.log.FileManager.readFromFile(FileManager.java:1560)
     at com.sleepycat.je.log.FileManager.readFromFile(FileManager.java:1498)
     at com.sleepycat.je.log.FileSource.getBytes(FileSource.java:56)
     at com.sleepycat.je.log.LogManager.getLogEntryFromLogSource(LogManager.java:861)
     at com.sleepycat.je.log.LogManager.getLogEntry(LogManager.java:790)
     at com.sleepycat.je.log.LogManager.getLogEntryAllowInvisibleAtRecovery(LogManager.java:751)
     at com.sleepycat.je.tree.IN.fetchTarget(IN.java:1320)
     at com.sleepycat.je.tree.BIN.fetchTarget(BIN.java:1367)
     at com.sleepycat.je.dbi.CursorImpl.fetchCurrent(CursorImpl.java:2499)
     at com.sleepycat.je.dbi.CursorImpl.getCurrentAlreadyLatched(CursorImpl.java:1545)
     at com.sleepycat.je.dbi.CursorImpl.getNextWithKeyChangeStatus(CursorImpl.java:1692)
     at com.sleepycat.je.dbi.CursorImpl.getNext(CursorImpl.java:1617)
     at com.sleepycat.je.cleaner.UtilizationProfile.getFirstFSLN(UtilizationProfile.java:1262)
     at com.sleepycat.je.cleaner.UtilizationProfile.populateCache(UtilizationProfile.java:1200)
     at com.sleepycat.je.recovery.RecoveryManager.recover(RecoveryManager.java:221)
     at com.sleepycat.je.dbi.EnvironmentImpl.finishInit(EnvironmentImpl.java:549)
     - locked <0x00002aaaf8009868> (a com.sleepycat.je.dbi.EnvironmentImpl)
     at com.sleepycat.je.dbi.DbEnvPool.getEnvironment(DbEnvPool.java:237)
     at com.sleepycat.je.Environment.makeEnvironmentImpl(Environment.java:229)
     at com.sleepycat.je.Environment.<init>(Environment.java:211)
     at com.sleepycat.je.Environment.<init>(Environment.java:165)
Stack trace #2:
"main" prio=10 tid=0x000000005622f000 nid=0x5d94 runnable [0x00000000419fe000]
java.lang.Thread.State: RUNNABLE
     at com.sleepycat.je.tree.IN.findEntry(IN.java:2086)
     at com.sleepycat.je.dbi.CursorImpl.searchAndPosition(CursorImpl.java:2194)
     at com.sleepycat.je.cleaner.UtilizationProfile.getFirstFSLN(UtilizationProfile.java:1242)
     at com.sleepycat.je.cleaner.UtilizationProfile.populateCache(UtilizationProfile.java:1200)
     at com.sleepycat.je.recovery.RecoveryManager.recover(RecoveryManager.java:221)
     at com.sleepycat.je.dbi.EnvironmentImpl.finishInit(EnvironmentImpl.java:549)
     - locked <0x00002aaaf8009868> (a com.sleepycat.je.dbi.EnvironmentImpl)
     at com.sleepycat.je.dbi.DbEnvPool.getEnvironment(DbEnvPool.java:237)
     at com.sleepycat.je.Environment.makeEnvironmentImpl(Environment.java:229)
     at com.sleepycat.je.Environment.<init>(Environment.java:211)
     at com.sleepycat.je.Environment.<init>(Environment.java:165)
It looks like it is spinning in UtilizationProfile.getFirstFSLN(). Examining the syscalls using strace shows that JE is looping around the same 3 log files over and over again (note the lseek calls on fd 147):
14719 lseek(147, 2284064, SEEK_SET) = 2284064
14719 read(147, "\310\f9\311\v\0\330\331\"\0:\0\0\0\2{\231\302\36\27\0\340\24\0\0\33\201\230\0\340\24\0"..., 4096) = 4096
14719 lseek(95, 3030708, SEEK_SET) = 3030708
14719 read(95, "B\17\36\373\v\0\350<.\0B\0\0\0\2{3\323\36\27\0+\21\0\0\210\221\230\0+\21\0"..., 4096) = 2469
14719 lseek(95, 3025672, SEEK_SET) = 3025672
14719 read(95, "#(\2571\v\0b*.\0\202\0\0\0\2{\26\323\36\27\0\0160\0\0f\221\230\0Z\22\0"..., 4096) = 4096
14719 lseek(74, 35084, SEEK_SET) = 35084
14719 read(74, "\361\34s\272\v\0\300\210\0\0h\0\0\0\2{\240\323\36\27\0\346\36\0\0\215\225\230\0\350\22\0"..., 4096) = 4096
14719 lseek(74, 90663, SEEK_SET) = 90663
14719 read(74, "\2\16P\341\v\0#;\1\0B\0\0\0\2{\275\323\36\27\0\366/\0\0003H.\0$\3\0"..., 4096) = 4096
14719 lseek(147, 2284064, SEEK_SET) = 2284064
14719 read(147, "\310\f9\311\v\0\330\331\"\0:\0\0\0\2{\231\302\36\27\0\340\24\0\0\33\201\230\0\340\24\0"..., 4096) = 4096
14719 lseek(95, 3030708, SEEK_SET) = 3030708
14719 read(95, "B\17\36\373\v\0\350<.\0B\0\0\0\2{3\323\36\27\0+\21\0\0\210\221\230\0+\21\0"..., 4096) = 2469
From the output of lsof we can determine the names of the log files associated with the above file descriptors, but I'm not sure if this is useful or not. We also ran DbVerifyLog against the entire DB log and it produced no results, so this indicates to me that the DB is not corrupt after all (although it could be that DbVerifyLog simply does not check the utilization profile meta data).
I had a look at the change log for 4.1.17 but couldn't see any relevant bugs. It's probably worth noting that this DB does not use HA, duplicates, or secondary indexes.
So I guess I have two questions:
1) Is this a bug? Presumably the DB should recover even in the event of a human error induced failure like this?
2) Can we recover the DB somehow, e.g. using DbDump/DbLoad?
Let me know if you need any additional information.
Cheers,
Matt

1) Is this a bug? Presumably the DB should recover even in the event of a human error induced failure like this?It is probably a bug, but it depends on exactly what happened during the original crash.
2) Can we recover the DB somehow, e.g. using DbDump/DbLoad?If you can't open the environment, only DbDump -R (salvage mode) can be used, which requires identifying the active data by hand. Not a good option.
Let me know if you need any additional information.Do you happen to have the original stack trace, where you ran out of FDs?
How long did the looping go on before you killed the process?
--mark

Slapd database environment corrupt; wrong log files removed

When our OSX 10.4.10 server boots up, slapd crashes out with a fatal error, followed by an unsuccessful attempt to recover the database. This is from the log:
Sep 22 22:41:49 xyz123 slapd[428]: @(#) $OpenLDAP: slapd 2.2.19 $\n
Sep 22 22:41:49 xyz123 slapd[428]: bdbbackinitialize: Sleepycat Software: Berkeley DB 4.2.52: (December 3, 2003)\n
Sep 22 22:41:49 xyz123 slapd[428]: bdbdbinit: Initializing BDB database\n
Sep 22 22:41:49 xyz123 slapd[428]: bdb(dc=xyz123,dc=mydomain,dc=com): DBENV->logflush: LSN of 3/2806706 past current end-of-log of 1/2458\n
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Sep 22 22:41:49 xyz123 slapd[428]: bdb(dc=xyz123,dc=mydomain,dc=com): gidNumber.bdb: unable to flush page: 0\n
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Sep 22 22:41:50 xyz123 slapd[428]: bdbdbopen: dbenv_open failed: DB_RUNRECOVERY: Fatal error, run database recovery (-30978)\n
Sep 22 22:41:50 xyz123 slapd[428]: backend_startup: bidbopen failed! (-30978)\n
Sep 22 22:41:50 xyz123 slapd[428]: bdb(dc=xyz123,dc=mydomain,dc=com): DBENV->lockid interface requires an environment configured for the locking subsystem\n
Sep 22 22:41:50 xyz123 slapd[428]: bdb(dc=xyz123,dc=mydomain,dc=com): DBENV->lockid interface requires an environment configured for the locking subsystem\n
Sep 22 22:41:50 xyz123 slapd[428]: bdb(dc=xyz123,dc=mydomain,dc=com): DBENV->lockid interface requires an environment configured for the locking subsystem\n
Sep 22 22:41:50 xyz123 slapd[428]: bdb(dc=xyz123,dc=mydomain,dc=com): DBENV->lockid interface requires an environment configured for the locking subsystem\n
Sep 22 22:41:50 xyz123 slapd[428]: bdb(dc=xyz123,dc=mydomain,dc=com): DBENV->lock_idfree interface requires an environment configured for the locking subsystem\n
Sep 22 22:41:50 xyz123 slapd[428]: bdb(dc=xyz123,dc=mydomain,dc=com): txn_checkpoint interface requires an environment configured for the transaction subsystem\n
Sep 22 22:41:50 xyz123 slapd[428]: bdbdbdestroy: txn_checkpoint failed: Invalid argument (22)\n
Sep 22 22:41:50 xyz123 slapd[428]: slapd stopped.\n
We are able to get it running by deleting the log file at /var/db/openldap/openldap-data/log.0000000001 and then rebooting. Thereafter the slapd.log complains:
Sep 23 20:30:30 xyz123 slapd[58]: bdb(dc=xyz123,dc=dc=mydomain,dc=com): DBENV->logflush: LSN of 1/467990 past current end-of-log of 1/226654\n
Sep 23 20:30:30 xyz123 slapd[58]: bdb(dc=xyz123,dc=dc=mydomain,dc=com): Database environment corrupt; the wrong log files may have been removed or incompatible database files imported from another environment\n
Sep 23 20:30:30 xyz123 slapd[58]: bdb(dc=xyz123,dc=dc=mydomain,dc=com): sn.bdb: unable to flush page: 0\n
We've tried running db_recover -c but that hasn't worked, or at least, we perhaps didn't do it right. We don't have a backup database that predates the existence of this problem.
I'd appreciate if anyone has help or could point us to a resource explaining what to do to get our slapd working right.

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I'm looking for the method to open the file and add 'cutom migration script' (some automatization).

Hi Poman.Pokrovskij,
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Hi All
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mycoffee wrote:
captfoss wrote:
mycoffee wrote:
This will be very easy for me to test but the structure of project will be changedWhy exactly is the structure of the project changing a bad thing?
Further, why can't you use the web project for testing and then the other convoluted way for deployment? Most professional systems have a different system for testing and actual builds.Good advice
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